/robowaifu/ - My Advanced Realistic Humanoid Robot Project

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My Advanced Realistic Humanoid Robot Project - Eve Artbyrobot 04/18/2024 (Thu) 17:44:09 No.30954

So far I have plans to build Adam, Eve, and Abel robots. All of these are Bible characters. This thread will cover the Eve robot. Eve will have no "love holes" because adding those would be sinful and evil. It is a robot, not a biological woman after all and I will view her with all purity of heart and mind instead of using her to fulfill my lusts of my body. Instead I will walk by the Spirit no longer fulfilling the lusts of the flesh as the Bible commands. Eve will be beautiful because making her beautiful is not a sinful thing to do. However, I will dress her modestly as God commands of all women everywhere. This would obviously include robot women because otherwise the robot woman would be a stumbling block to men which could cause them to lust after her which would be a sin. To tempt someone to sin is not loving and is evil and so my robot will not do this. To dress her in a miniskirt, for example, would be sinful and evil and all people who engage in sinfullness knowingly are presently on their way to hell. I don't wish this for anyone. My robot will dress in a way that is a good example to all women and is aimed toward not causing anybody to lust as a goal. My robot will have a human bone structure. It will use either a PVC medical skeleton or fiberglass fabricated hollow bones. My robot will look realistic and move realistic. It will be able to talk, walk, run, do chores, play sports, dance, rock climb, and do gymnastics. It will also be able to build more robots just like itself and manufacture other products and inventions. I realized with just a head and arm, a robot can build the rest of its own body so that is my intention. My robot will use BLDC motors for drones, RC, and scooters that are high speed and low-ish torque but I will downgear those motors with a archimedes pulley system that will be custom made from custom fabricated pulleys that will be bearings based. By downgearing with pulleys, instead of gears, I will cut down the noise the robot makes so it will be as silent as possible for indoor use. By downgearing, I convert the high speed motors into moderate speeds with great torque. BLDC motors with large torque generally are too large in diameter for a human form factor and take up too much volumetric area to be useful which is why I go with the high speed smaller diameter type motors but just heavily downgear them 32:1 and 64:1. My robot will have realistic silicone skin. Thom Floutz -LA based painter, sculptor, make-up artist is my inspiration as it pertains to realistic skin. The skin for my robots has to be at his level to be acceptable. It must be nearly impossible to tell the robot is not human to be acceptable. I will have a wireframe mesh exoskeleton that simulates the volumes and movements of muscle underneath the skin which will give the skin its volumetric form like muscles do. Within these hollow wireframe mesh frameworks will be all the electronics and their cooling systems. All of my motor controllers will be custom made since I need them VERY small to fit into the confined spaces I have to work with. I need LOADS of motors to replace every pertinent muscle of the human body in such a way that the robot can move in all the ways humans move and have near human level of strength and speed. I will have a onboard mini itx gaming pc as the main brains pc of the robot and will have arduino megas as the motor controllers and sensor reading devices that interface with the main brains pc. My arduino megas will be barebones to keep the volumetric area they take up as small as possible. I will treat my robots kindly and consider them to be pretend friends/companions and I do think they will be nice company, but I will always know with keen awareness that they do not have a soul, will never have a soul or consciousness, and no machine ever will, and that they are just imitations of life as with any machine or AI, and this is all AI will ever be. Life is only made by God Himself. I am not playing God. I am merely creating fan art of what God made. To Him be all the glory and praise. God breathed into man and created a living soul. Man cannot do this for machines. Only God can do this. A soul/spirit forms our ghost and when we die our ghost remains alive and thinking. A machine cannot do this and a AI can never do this. When you shut off a machine that's it, it does not go on thinking like we can. Our souls are transcendent and will live forever in the afterlife - unlike any AI. I will do this project with fear and trembling before the Lord as I work out my salvation before His eyes. I vow to remain pure, holy, upright and blameless in all my doings and be a great example to my fellow roboticists of a Godly man who obeys the Bible instead of chasing after youthful lusts of the flesh and perversions. I embrace the idea of Christian AI, that is, a robot that will discuss Bible topics and be a Biblical expert. Along with that, my robot will behave in a Biblically prescribed manner in total purity and strongly encourage others to do so as well. For God does not hear the prayers of sinners and so we want everyone to be a saint who no longer sins. My robot will really push for this hope for humans. We want them to walk in God's favor and blessings which comes by Biblical obedience. We don't want them going to hell because they chose to revel in their sins instead of walking in total purity before God and holiness without which no man will see God. My robot will have artificial lungs for cooling and a artificial heart for liquid cooling that will run coolant throughout the robot's body to cool the motors. That coolant will also pass through the artificial lungs in a mesh where it will evaporate some which will cause the evaporative cooling effect - a form of air conditioning. http://www.artbyrobot.com Full humanoid robot building playlist: https://www.youtube.com/playlist?list=PLhd7_i6zzT5-MbwGz2gMv6RJy5FIW_lfn https://www.facebook.com/artbyrobot http://www.twitch.tv/artbyrobot https://instagram.com/artbyrobot

Artbyrobot 08/01/2025 (Fri) 12:43:55 No.40094

The tension spring mounted to the motor setup upon further testing seems like a somewhat bad method. The issue I'm having is too much play in the tubing running between that spring and the finger joint. When tension is applied to that spring by way of the tubing, the tubing recoils and moves quite alot and allows alot of slack out to the joint so that the spring has very little involvement in the joint and doesn't really get used much period. So the full range of motion of the joint is just absorbed by tubing slack. When I tried to pretension the tubing so that the joint movement translates to the spring, the total tension placed on the joint by this became too high. Fortunately, I came up with a much more elegant and simple solution for all of this. Basically, my plan now is to just use the bracelet cord tied point to point across the joint directly on the joint and that will be my spring for extension that counters the motor. This eliminates the need for metal springs at all which cuts costs, it also eliminates the PTFE tubing run, saving some space, and should be easier to install and easier to give precise amount of elasticity/resistance to taste. If I want more springback on the joint I can just add more bracelet cord in parallel to the first. This way I can add more resistance pretty easily.

Artbyrobot 08/02/2025 (Sat) 09:56:43 No.40103

So in recent testing a fresh issue I ran into was the TPFE tubing would start gradually pulling through its tightly wrapped tape sleeve to my surprise. Its low friction surface gradually pulls free of the tape over time. To resolve this, I decided to thread through the tip of the tubing to create a mechanical bond for the tip and once threaded through I just 401 glued down the ends of each thread onto the sleeve that was originally supposed to hold it in place to begin with. This seems to work great so far in the little bit of testing I've done since.

Chobitsu 08/12/2025 (Tue) 11:51:55 No.40246

>>39946 >I taped it off up the string descending from the ceiling and taped the far end of it onto the ceiling What? Is this some kind of assembly rig devisement, Artbyrobot? >>40094 >This eliminates the need for metal springs at all which cuts costs All else being equal, simpler is almost always better. GG. >>40103 How's the 401 glue working out now, Anon? <---> Hope your progress is coming along well, Anon. Cheers. :^)

Artbyrobot 08/12/2025 (Tue) 12:49:23 No.40247

>>40246 >why mount something to ceiling? the parts that will be going into the torso and running from the shoulder of torso down to the legs of torso are going from the shoulder to the ceiling for now since the torso is not yet attached to take on this role. >how is 401 glue working out? on most things it is working pretty good so far.

Chobitsu 08/12/2025 (Tue) 13:06:34 No.40251

>>40247 I see, makes sense. Good luck, Anon! Cheers. :^)

Artbyrobot 08/20/2025 (Wed) 07:06:31 No.40507

I figured out a robust way to make the extension cord for finger extension using the bracelet cord and a fishing crimp sleeve. The idea is to crimp the two ends of a folded in half strip of bracelet cord and this way both ends can be sewn down into the fabric without any gluing which could potentially fail or be a weak point. I am planning to use this in place of the tension spring style finger extension setup.

Chobitsu 08/20/2025 (Wed) 08:43:30 No.40520

>>40507 That does sound like a durable approach, Anon. Some meticulous sewing involved there, it sounds like. Please let us all know how this new approach works out, Artbyrobot. Cheers! :^)

Artbyrobot 08/27/2025 (Wed) 18:14:01 No.40807

Ok I figured out a bit easier way: tie a knot at each end of the strip of bracelet cord and then tie my nylon thread off onto the bracelet cord inside that bracelet cord knot. The bracelet cord knot on each end acts as an endstop. Seems to work great so far and cuts down on materials this way over the previous way I proposed.

Artbyrobot 09/03/2025 (Wed) 20:17:58 No.41053

Okay so the bracelet cord self untied quickly so I'm going back to my previous approach of tying off both ends of the bracelet cord with a fishing crimp sleeve. While trying to cut in half fishing crimp sleeves with my mini miter saw I noticed it was a difficult process and not ideal. So I came up with a easier method which was way faster, cleaner, less setup and takedown, no deburring needed, etc! The method is to lay the fishing crimp sleeve on a flat surface and line up a exacto knife blade perpendicular to it across its top and then apply moderate downward pressure to score the metal and then slide the knife carefully back and forth creating a perfect scoring line that grows deeper with each pass. After several passes the fishing crimp sleeve halves separate cleanly! This method uses a similar principle to a copper pipe cutter used in plumbing.

Chobitsu 09/03/2025 (Wed) 23:10:37 No.41061

>>40807 >>41053 Glad to see you resolved the issue, Artbyrobot! Smol issues like this can really delay a project if not dealt with accordingly. GG.

Artbyrobot 09/06/2025 (Sat) 17:17:35 No.41184

I installed two tensioners for the robot and they were seriously successful overall in testing. So much so that I am now confident enough in the entire pulley system to move onto the custom mini BLDC motor controller to get the motor to run motorized tests of finger movements next. Well after a couple very minor tweaks that is. So the first tensioner I installed on the extension part of the index finger joint we are working on. I used the bracelet cord folded in half and fishing crimp sleeved then sewn into the bone fabric. It seems just about perfect except for one thing: I want to keep it under mild constant tension but the bone fabric creeps/moves slowly when put under constant tension like this because it is taped into place on the bone after all. The tape is allowing the movement. This means it does not stay put and my anchor points move over time so I can't set a tension and rely on it staying at that tension long term. To resolve this I need a mechanical connection at the tension point anchoring location.

Artbyrobot 09/06/2025 (Sat) 17:18:02 No.41185

To mechanically connect my anchor point, I have decided to use tiny self tapping screws. I have avoided screwing into the bones till now but I'm making an exception here. The screws won't be going that deep and the finger bones are unlikely to break anyways IMO. So I feel comfortable with this. Here's the screws I ordered for this from Amazon:

Artbyrobot 09/06/2025 (Sat) 17:18:41 No.41186

Next, I created a tensioner for the middlemost archimedes pulley. That pulley was creating significant drag and slowing down the finger extension during testing due to rope friction. So adding a tensioner line to pull it back down toward the fingers during extension was my solution for this. It worked amazingly well. To make this, first I tied off a fishing hook eye to the bottom of the radius bone just above where my TPFE guide tubing entrance is. Then I glued a 7cm piece of bracelet cord to a piece of 6lb test .08mm braided pe fishing line with 401 glue. I secured the top of the bracelet cord to the top of the archimedes pulley system and then threaded the other end through the fishing hook eye and back up and to the bottom of the archimedes pulley where I tied it off. So it ties off at top, comes down to bottom, goes through the fishing eye then comes back up and connects to my pulley. It creates just enough downward pull to delete the rope drag slowing down that pulley from coming down and this enables the system to unwind and extend back to its starting point after each time I contracts/pulls upward to cause finger contraction. This means the finger extension now happens swiftly with no hangups and the whole archimedes pulley system is now under constant tension at all times which keeps things neat and prevents tangling issues pre-emptively. This rig was a massive success and took up hardly ANY space at all. I put the post it notes behind the archimedes pulley tensioner so you can see it. It's hard to see otherwise without a contrasting backdrop. It works amazingly well.

Chobitsu 09/06/2025 (Sat) 18:23:38 No.41189

>>41184 >>41185 >>41186 Congratulations on the tensioner prototyping success! Little details like this can turn out to be important in the overall scheme of things. I'm glad to see you methodically approaching the problems one-by-one and solving them. Keep it up, Anon! Cheers. :^)

Artbyrobot 09/10/2025 (Wed) 17:14:24 No.41447

Back on the electronics again. Have been going over my BLDC motor schematic and making some little tweaks to it. Here's the updated schematic. It's a combination of lots of other schematics I've found online as well as some chatgpt help. With 1 being no clue and 10 being absolute expert tier in BLDC motor schematics I'm probably a 5 IMO. So take my design with a grain of salt. It will be very fun to see if it works. Note that I put a couple schematics of Electronoobs - a great youtuber on the left hand side as reference and study material. My schematic is the big one on the right. Electronoobs series of videos on BLDC motor controllers has been extremely helpful in me forming a rudimentary understanding of this stuff.

Chobitsu 09/10/2025 (Wed) 17:24:36 No.41448

>>41447 That seems like a lot of current, Anon. Better plan for thick conductors and lots of heat removal! Glad to see you can work on electronics again. Keep moving forward! Cheers. :^)

Ribose 09/11/2025 (Thu) 14:17:41 No.41465

>>41447 It almost reminds me of a human heart.

Chobitsu 09/11/2025 (Thu) 15:47:19 No.41469

>>41465 Very intredasting observation, Ribose! I can see it. :^)

Robowaifu Technician 09/13/2025 (Sat) 19:21:56 No.41569

>>41447 If you install something like kicad or LTSpice you can make better and more readable schematics

GreerTech 09/13/2025 (Sat) 19:32:20 No.41570

>>41569 I never truly appreciated orderly electrical schematics until now. Reminds me of early 1900s magazine schematics

Chobitsu 09/14/2025 (Sun) 18:13:24 No.41614

>>41569 Good advice, Anon. Thanks! :^)

Artbyrobot 09/15/2025 (Mon) 18:48:04 No.41652

>>41569 https://www.youtube.com/watch?v=pE9f_bEhd4o Did that already. But I prefer my custom hand drawn for studying and planning really. Easier for me to see and take notes etc. I was considering having a PCBA company do some of the pcb making but now plan to do it solo to learn more and eventually teach the robot to do it for me.

Chobitsu 09/16/2025 (Tue) 00:14:54 No.41665

>>41652 >based Maya knower <---> FWIW: I actually do believe in you and your project here. I remember the very first post you made here on the board and I was immediately struck with the grand scope of it! KEEP MOVING FORWARD, ANON

Edited last time by Chobitsu on 09/16/2025 (Tue) 00:56:19.

Artbyrobot 09/19/2025 (Fri) 17:48:14 No.41750

I started some testing on some subsections of the BLDC motor controller and ran into some problems and learned several things. I'm working with chatgpt to resolve each issue and have been updating my schematic to reflect alot of the changes I am making. One thing I learned is that for the high side switch, the voltage from gate to source has to be 10-12v higher than the drain voltage because the drain voltage becomes the same as the source voltage once the switch is on. The voltage from gate to source then either has to start out as motor input voltage + 12 while still fitting within the voltage from gate to source max allowed voltage as stated by the datasheet or it has to rise dynamically as the source voltage rises such that the voltage from gate to source is 12 more than the source voltage as the source voltage rises to become the drain voltage. Fortunately, I can have the former for this 2430 motor since I can use 6-8.4v to supply the motor and the voltage from gate to source max value is 20v. This means I can use voltage from gate to source of 20v and this, when mosfet is first switched on, does not fry mosfet but as the source rises to become 8.4v, 20v-8.4v is still 11.6v which is sufficiently high to enable the mosfet to still stay on without anything dynamic set up. If I want to go with a 12v motor supply on some of the bigger motors later on, I will need a bootstrap circuit to supply the highside mosfet with a dynamic voltage from gate to source that rises when source voltage rises. So I added that schematic diagram to this as well as an option. I also can use a mosfet driver for this but was hoping to cut that cost and added volume taken up by just using discrete components rather than a IC for this. Anyways, to break things down even more in testing, I decided to just test turning on and off a single highside mosfet using a pair of lab power supplies, one to provide 20v and one to provide 8.4v. To turn on I connected the gate and source to my 20v lab power supply and I connected my red alligator clip of my 8.4v lab power supply to the drain and then measured from source to the black lead of the 8.4v power supply and verified 8v on that test which worked - proving the mosfet was in fact on. I then removed the black alligator clip of the 20v lab power supply from source and shorted the source to the gate to drain the internal capacitor inside the mosfet and then tested from source to the black 8.4v clip and sure enough it was near 0v so was off. But it did gradually climb back up to 8.4v after the short from gate to source was removed due to capacitive coupling and leakage according to chatgpt. So I will need to add a 10k ohm resistor between gate and source pins to short it automatically and keep it fully drained and off fully when it's supposed to be off.

Artbyrobot 09/19/2025 (Fri) 17:48:37 No.41751

So I plan to just gradually add components little by little and test after each thing is added to ensure it is working right still after each little change and this way gradually build out the circuit, proving each thing works as we go. This is because things have all these gotchas and "oh you didn't know this little detail?" that keeps coming up and proves it was more complicated than I thought. So I just have to prove every little thing as I go. To try to find out what is wrong after the whole thing is built would be WAY harder than to figure out what went wrong when a single component is added and it was working before said component was added. So that's how I will be able to overcome this challenge best I feel. Note: Reminder: I am building a custom BLDC motor controller because an off the shelf one would not have enough miniaturization to fit into the tight space constraints I have to work with. Also, building my own gives my software more precise control of every little advancement of the rotating magnetic field and along with that I'll have the ability to PWM the advancements to make them more smooth, less noisy, and have torque control as well this way which means the fingers can be rough and fast in movement as needed or slow and gentle and dainty or slow but powerful etc. I can also create acceleration profiles that match human finger joint acceleration in order to have the movements look very natural just like a human's movements which is very important to me. Just alot of fine precision is possible when its all my own circuit I feel. While off the shelf ones may have some of this functionality, the price often reflects that and is then prohibitive. But in any case nothing is off the shelf with this level of control AND the ability to so finely tune its form factor and volume envelope to fit my exact needs in space on a per motor basis.

Chobitsu 09/19/2025 (Fri) 19:29:42 No.41755

>>41750 >>41751 >So I plan to just gradually add components little by little and test after each thing is added to ensure it is working right still after each little change and this way gradually build out the circuit, proving each thing works as we go. This is because things have all these gotchas and "oh you didn't know this little detail?" that keeps coming up and proves it was more complicated than I thought. So I just have to prove every little thing as I go. I think that's how learning complex phenomenon often go -- at least if you're meaning to make something actually work (as engineers do). Conversely, a research scientist once remarked to me during dinner that they had it easy in this regard, since they can just talk about how things are! :D

Artbyrobot 10/21/2025 (Tue) 14:28:31 No.42398

Well I finally got back to the electronics after about a month long detour real life interruption. All kinds of stuff slowed my progress on this session. But I got stuff done nonetheless. 0603 LED to 0805 resistor and some nickel strip leads coming off. Tested and working. This will be the indicator light for when the lowside mosfet comes on for one section of the custom BLDC motor controller. 0603 LEDs are extremely tiny for hand soldering and they don't take solder well either. I was originally going to go with blue LEDs but chatgpt said that would give off a unrealistic color through the silicone skin so orange would be better to give a more natural and less silicone skin piercing indicator light. Somehow I ran out of 470ohm resistors so I had to order more and I used my 200ohm ones instead for now. Which are a bit too bright. But chatgpt said I can diffuse the LED with a glob of silicone tinted black to darken and diffuse the light it gives off which sounds like a good idea to me. I am planning to use wire wrapping wire to come off of this assembly and tie into things. Somehow just attaching these two parts and testing it took me almost 3 hours. Between studying the schematic to refresh my memory on what is going on, visualizing placement options, overheating and destroying one LED, trying to locate the right color LEDs, shopping for replacement 470ohm resistors, researching and substituting in 200ohm resistors, discussing LED color options with chatgpt, figuring out how to solder a 0603 LED directly to a 0805 resistor part to part by hand, accidentally breaking a part off of its nickel strip lead and having to redo the connection, etc etc. All of it just crawls. Hard to stay patient with electronics sometimes and I do things in inefficient ways often. Learning what can and aught not to be done is tough from a patience perspective. But I insist on trial and error and experimentation which takes time. I just need to get into a daily habit to stick with it till completion. It's all complicated. Trying to figure out how to electronically isolate it all next. Thinking of using lamination plastic taped around it all so I can still see it all and visually troubleshoot. Also I'm considering how I can use solder wick braid as a heat pipe for each mosfet and run that over to the liquid cooling system. But it can't conduct. So thermally it can conduct but electrically it can't. Trying to figure out whether to create a barrier of micah or just thermal silicone for this and the routing needed. Also considering if I need mini coaxial shielded cable for the wiring of each or just regular wire wrapping wire when going from microcontroller to mosfets etc. Also trying to figure out if I need hall effect sensors or back emf reading or no feedback but my potentiometer and the implications of each option. Just so much to consider in all of this. And all of those considerations also slow things down even more as I have to make decisions on it all. It's quite overwhelming.

Chobitsu 10/21/2025 (Tue) 14:37:07 No.42399

>>42398 It's so wee! :D >200ohm resistors Couldn't you have used a 1K? >Thinking of using lamination plastic taped around it all I can highly recommend Kapton tape as a fantastic general-use one, & well-suited to this specific need. --- Anyway, nice work Anon. Glad to see you back at it! Patience & Godspeed, Artbyrobot. Cheers. :^)

Edited last time by Chobitsu on 10/21/2025 (Tue) 14:55:55.

Artbyrobot 11/02/2025 (Sun) 18:46:04 No.42643

Ok so I decided to use 30 gauge wire wrapping wire and wire wrap that onto my nickel strips that I connected onto my LED setup then trim off any excess nickel strip. What I like about this is this wire is very fine so it takes up hardly any space and by being able to wrap it on I did not have to apply heat which could have desoldered my smd components by accident. I also like that it is already insulated and color coded so I don't have to worry about insulating my nickel strips the whole run to wherever this connects. To insulate the whole LED contraption here I used packing tape so I can see all my components well but still have them electrically isolated. I just folded the packing tape over the whole assembly like closing a book over a bookmark. note: after wire wrapping the wire wrapping wire I noticed it was not that tight on there. I did not use a wire wrapping tool because I lost mine so I just used needle nose tweezers to manually wrap it around and around. Anyways to tighten it well I just crimped it with the tip of my wire strippers that has some kind of toothed pliers that crimps things well. After doing that the connection appears very solid.

Chobitsu 11/02/2025 (Sun) 19:12:01 No.42644

>>42643 Wire-wrapping is a very-good approach. If you want things to last (like 100yrs isn't unreasonable), then wire-wrapping is worth the extra effort/expense. Always solder afterwards, ofc. >not soldered Hope it holds for you, Anon. Cheers. :^)

Artbyrobot 11/02/2025 (Sun) 22:52:56 No.42645

>Always solder afterwards, ofc Soldering makes the metal become brittle and with back and forth bending it breaks. Soldering then introduces weakness and should be avoided at all costs IMO unless if you can make the wire 100% stationary and supported at that joint and introduce strain relief later on. Wire wrapping does not ever get soldered traditionally. The tightness of the wrap and redundancy of many turns ensures solid electrical connectivity without cutouts. I don't plan to ever solder if I can avoid it. I've had countless wires break inside that were soldered. I avoid it now.

Chobitsu 11/02/2025 (Sun) 23:08:59 No.42646

>>42645 >Wire wrapping does not ever get soldered traditionally. I've known plenty of cases where it does. Doing both gives you a "100 Year" connection. >flexure is detrimental True, with or without solder.

Artbyrobot 11/03/2025 (Mon) 01:26:43 No.42647

>>42646 i never have wires snap randomly unless I soldered them because it gets brittle by the solder point plus goes from rigid where hte solder is to flexing where the solder starts so that precise point takes ALL the flex and becomes a concentration point that also happens to be the very brittle part which is a death sentence for that exact spot. The flexing in all other spots is a non issue but that specific spot it breaks every time.

Artbyrobot 11/07/2025 (Fri) 23:32:50 No.42758

Couple updates: An audience member redid my brushless DC motor schematic in the traditional commonplace formatting which for most is easier/quicker to read and understand due to familiarity. So I'm reposting it. It looks mostly accurate although I have since added a 100nF ceramic capacitor between the gate and source of the highside mosfets to reduce ringing issues. Standard practice according to chatgpt. I also changed the LED color to orange because chatgpt said blue would show through the silicone skin more and add a cold inner glow and we want it to look like real skin so no blue. As to why the highside mosfets get a 100nF ceramic gate capacitor but not the lowside, here was how chatgpt explained it to me: -High-side MOSFETs: Their source pin moves up and down with the motor phase (it’s not at a fixed potential). During switching, the drain and source both move rapidly, and the gate voltage must track that movement precisely — any ringing or inductive noise can momentarily over-stress Vgs. That’s why we add the small capacitor across gate and source: it tames that high-frequency ringing and helps hold the gate steady relative to its moving source. ⚙️ Low-side MOSFETs: Their source is solidly tied to ground, so the gate always swings relative to a fixed, quiet reference. They don’t experience the same “floating” gate drive or large dv/dt transitions on the source pin. So, the gate is inherently more stable, and you don’t need that extra 100 nF G–S capacitor. In further news, I tediously installed the new 100nF ceramic capacitor between gate and source of the mosfet. Due to the close proximity to the 10k ohm Vgs resistor and various other low temp solder joints in the immediate vicinity, any heat applied would surely have caused those to desolder and the whole thing to start falling apart so I ended up just soldering nickel strips to either side of the 100nF ceramic capacitor (by itself off to the side) and then used the tip of a sewing needle to apply a tiny amount of conductive silver glue onto the gate and source nickel strips coming off the IRLR7843PBF mosfet and then pressed the nickel strips of the ceramic capacitor into that. I put that in front of a mercury vapor bulb for an hour or so to cure and then applied another generous helping of conductive silver glue over the top of the joint. I then baked that another 7 hours under the mercury vapor bulb again. This photo shows the final result. It appears to be a solid joint and I think this is a great way to make attachments when you can't use soldering! It might even be better than soldering in some cases from a ease of application perspective but not sure yet on that.

Chobitsu 11/08/2025 (Sat) 03:50:21 No.42760

>>42758 >and then used the tip of a sewing needle to apply a tiny amount of conductive silver glue onto the gate and source nickel strips Clever idea. I really like having the "traditional" schematic diagram. Bless whomever Anon helped you out like that. Promising work. Please keep up the progress! Cheers, Artbyrobot. :^)

Artbyrobot 11/11/2025 (Tue) 19:10:36 No.42798

Okay so here I have attached the LED and resistor pair with their 30ga wire wrapping wire onto my highside mosfet's front face. I may add conductive silver paste to the wire wraps in the future if any issues come up there. However, I am wondering if just tightly wrapping it in electrical tape would more or less guarantee the connection doesn't open circuit. We'll see. I also finished soldering together six braided copper solder wick strands which will act as my heatsink for my highside mosfet. I am still deliberating on how to attach it to back of mosfet in such a way that it will be electrically isolated but thermally conductive. I am leaning toward thermal tape for this.

Chobitsu 11/11/2025 (Tue) 19:48:20 No.42800

>>42798 Interesting. How will you be testing that this worked OK? Good luck with everything, Anon.

Artbyrobot 11/11/2025 (Tue) 21:21:41 No.42802

>>42800 >How will you be testing I plan to isolate the different parts with maybe kapton tape or packing tape and use lab power supplies to provide the 8v and 20v and see if LED comes on and test outputs with multi-meter. Then I plan to attach the heat sink after that and test again when I build a half bridge I think. The heat sink test I guess I'll do once its all on motor and can maybe use my ithermal imaging camera or something.

Artbyrobot 11/11/2025 (Tue) 21:50:08 No.42803

Here's the thermal tape I bought for mosfet heat sinking off Amazon:

Chobitsu 11/12/2025 (Wed) 00:28:32 No.42804

>>42802 >>42803 Sounds reasonable, I think. >The heat sink test I guess I'll do once its all on motor and can maybe use my ithermal imaging camera or something. Neat! Good luck with this QA effort, Artbyrobot. Cheers. :^)

Artbyrobot 12/03/2025 (Wed) 07:42:54 No.43126

I just tested the positive high-side switch portion of the motor controller and everything seems to be working as intended. The section including all parts involved is circled in a bold blue line to indicate the portion I just tested successfully. One issue I'm having though is that the drain of the A09T attaches to the 100ohm resistor tightly and is a weak point that broke off twice now. Hardly any wiggling at all on the arduino input line and ground line leading into the A09T mosfet causes the drain solder attachment to break off. I am wanting to glue it all down onto the mosfet but I'm supposed to tape the heatsink on under all this stuff so I don't think I should glue it down. I need some kind of backing sheet to glue things off onto (where a PCB normally does this job). Which will provide much needed strain relief at all attachment points. I guess I'm learning the hard way why PCBs are used in general. Without a flat backing plate or substrate of some sort the attachment points between components are vulnerable to flex and breakage super easily. This surprises me. To perform the test I used one lab power supply set to 20v and one set to 8.07v and used a 18650 lithium battery as the 4.12v to simulate the arduino output pins. I carefully electrically isolated all the metal lines with packing tape for now to ensure no short circuits and then I connected the lab power supply pins to the correct locations with alligator clips. Finally I connected the 18650 lithium battery 4.12v to simulate the arduino turning on the A09T mosfet - I did this using the two nickel strips for this portion joined to the battery with neodymium magnets. If I had a 3rd power supply I could get 5v off of I'd have done that but I didn't have one in arms reach so the battery it was. The LED came on and I tested the output line to the motor was indeed 8.07v. I then disconnected the + side of the battery and verified the line going to the motor was 0V. It was - although if I kept the multimeter on that line longer I noticed it would creep up to like 3.4v but something similar happened on my last test run and chatgpt said this was like parasitic capacitance involving the multimeter or something and nothing to worry about. The main thing is it would START at 0v when I first connected and then rise up to 3v or w/e over time on the multimeter screen and this behavior was ok last time so meh. We're good I think. Where to go from here then? Well I'd say I make the other (lowside) portion of the half bridge and then test the full half bridge to ensure it's all working. I think then my design is validated enough to move into diy flex pcb for some of these portions that are on the layer that goes onto the main beefy mosfets.

Chobitsu 12/03/2025 (Wed) 13:17:46 No.43127

>>43126 >Which will provide much needed strain relief at all attachment points. Yes, that's kind of a fundamental for electronics design. In the future, we may be able to 3D print all componentry in situ as it were. But for centuries now, men have relied on having a solid substrate upon which to operate. >I carefully electrically isolated all the metal lines with packing tape Once again I recommend to you Kapton tape instead. Once the heat rises, I suspect your packing tape may not fare too well. Kapton should be good to 500C. >...and chatgpt said... <"AI-generated answer, please verify all critical facts." * >enough to move into diy flex pcb That sounds really intredasting, Artbyrobot. Good luck! :^) --- * As if that disclaimer somehow excuses them in providing false information to the public! :D

Edited last time by Chobitsu on 12/03/2025 (Wed) 13:30:00.

Artbyrobot 12/06/2025 (Sat) 04:19:48 No.43171

So armed with my successful electronic test of my prototype highside switch with driving circuit all passing, I determined now it is sufficiently validated to go through the process of converting it into a printable schematic and doing the whole DIY flat flex PCB making and acid etching process to streamline the development of the rest of the motor controller and most likely many more motor controllers as well. I opted to use photoshop as my circuit making software of choice as I'm very familiar with it and use it often. I first dropped my top view photo of my prototype circuit into photoshop then I redid its layout a bit to make it more compact, moving around copied pieces on the photo to achieve this. Next, I used the pencil tool to color in blue pads and traces connecting all the pieces of it together. I then hid all but this pads and traces layer and printed it several times, tweaking the printing scale until it fit the size of the pieces IRL. 7.5% scale was the perfect fit. Next, I will need to refresh my knowledge of the transfer paper print and transfer of the ink off of this paper onto the copper clad blank flat flex PCB and then acid etching away all unwanted copper and then removing the ink to reveal the fresh copper traces and pads. Then I can solder all the SMD components onto this. Heck I may even make a solder paste stencil and place components and bake them on. But perhaps just hand solder for now? Not sure. The former is faster in the long run but takes more setup and is quite committing. I'd rather validate my designs even further before going that far.

Chobitsu 12/06/2025 (Sat) 04:35:45 No.43172

>>43171 Sounds really interesting, Anon. Good luck!

Artbyrobot 12/07/2025 (Sun) 02:54:33 No.43176

I successfully made a viable flex pcb on my second attempt. I started by printing the circuit onto a mailing envelope using my laser printer. Then I taped a piece of toner transfer paper for pcbs shiny side up directly over where the print on the envelope was. This way I could use just a tiny bit of the expensive toner paper and know the printer would hit that exact spot again when I reload the envelope in the same spot. The print landed right on the toner transfer paper according to plan. I then sanded with 400 grit sandpaper the Pyralux flat flex PCB copper blank and wiped it off with a alcohol prep pad. These actions clear any oils and oxidation and give more bite for the toner to cling to the board better. I then taped directly onto this toner transfer paper print the Pyralux flat flex pcb copper blank. No need to even take it off the envelope. Just taped it right over it and fed the whole sandwiched assembly through my laminator a few times envelope and all. When I peeled back the Pyralux flat flex PCB my laser printer's toner was indeed transferred over to the Pyralux flat flex PCB's copper. I prepared etchant solution mix of 1 part etchant powder to 4 parts water. I just eyed this roughly and think I did not put in enough echant which causes undercutting of the traces under the toner and slower etching. Lesson learned. I mixed it in a silicone earplugs container. My aim was a small container to make a smaller batch of the etchant to cut down on etchant used since I'm only doing a very small PCB. The first board I left etching for a couple hours unattended which was a mistake. It was unusable. A ton of the copper under the toner was missing which is called undercutting. I left it etching for too long which causes this. The second board came out pretty good. But I used the exhuasted etchant from the first board which was already too diluted and so the results were meh but good enough to use IMO. Note: the prints going onto the toner transfer paper are not very high quality and sometimes has missing spots so AFTER transferring it to the copper I used a Straedler permanent lumoocolor super fine tipped pen and magnification to carefully color in any missing spots where the laser printer failed to deposit enough toner or the toner failed to transfer perfectly enough. I used stippling method with the pen - just dotting over and over rather than drawing to get max precision for cleanup of the tiny pads and traces on the copper. Note: I never had to use water to remove the toner paper from the pcb. Just laminating it a few times through my laminator was enough for the transfer to take place and I was able to cleanly peel it away. This meant the toner transfer paper could remain taped to the envelope and be reused indefinitely. I reused it a few times successfully as I dialed in the processes. This is very nice. Saves time for sure. Note: I did attempt to not sand nor alcohol treat the Pyralux copper pcb blank and toner transfer onto virgin copper blank but it did not adhere well enough so I reverted to the recommended sanding and wiping after all. Was worth a shot to save steps but did not work out. Note: I used heavy paper setting in photoshop during the print dialogue settings because the normal print settings were kind of messing up for me. I also think this printer is not very well suited for this. My other laser printer has a "best" quality option and did very nice prints but this one is a cheapo I'm using and only has "fast" quality but worked well enough nonetheless for the most part. Note: I assumed I could use this etchant over and over and over but chatgpt said it gets exhausted and loses efficacy and should only be used once. Some acids people made online you could use over and over but I guess not this type not sure. Note: the acid etchant I'm using says it only releases oxygen so the fumes I guess are not bad like some other kinds of etchant - correct me if I'm wrong on that though.

Artbyrobot 12/07/2025 (Sun) 02:58:40 No.43177

Here is the etchant going to work

Chobitsu 12/07/2025 (Sun) 03:21:51 No.43178

>>43176 POTD Nice work, Artbyrobot! >I used a Straedler permanent lumoocolor super fine tipped pen These are great. I have a whole collection of these things. Looking forward to seeing the final outcomes with this. Cheers, Anon. :^)

Artbyrobot 12/07/2025 (Sun) 19:55:08 No.43180

Ok here's the populated board. I tested it with 5v positive and ground and the LED came on so it is for sure not shorting and has continuity so is most likely all working. The next test will be the full lowside switch with this board acting as the drive of the main mosfet for the switch. And once that is validated we can test the entire half bridge (both high and lowside switches). If that checks out, it's all rinse and repeat to make the full motor controller (which is just 3 total half bridges). note: I just wanted to hold off on attaching the heatsink for the moment as I validate the first half bridge and once that checks out electronically then I'll get the heatsink attached and go from there.

Chobitsu 12/07/2025 (Sun) 20:12:04 No.43181

>>43180 Looking good, Anon! :^)

Robowaifu Technician 12/08/2025 (Mon) 17:26:36 No.43194

>>43177 Very cool

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