My Advanced Realistic Humanoid Robots Project

My robots will use low cost BLDC motors commonly used 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 robots make so they 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. In my opinion, brushed DC motors are too loud for high quality indoor robotics and way less powerful than an equivalently sized BLDC motor, so I won't be using them at all in my robots.

My robots will have realistic silicone skin. Thom Floutz -LA based painter, sculptor, and 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 robots can move in all the ways humans move and have at least human level 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.

Project Logs

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Adding Breakout Wires for PCB Testing
Larry • 08/09/2026 at 21:44 • 0 comments

I soldered on 30ga wrapping wire for testing the PCB. The 3 on the front are 5v+ from microcontroller that tells this IC to be in "on" mode, ground from microcontroller, and PWM from microcontroller. The 2 on the back side are +8v and 0v/gnd from the batteries. This was shockingly quite hard to attach these. It's all so dang tiny. Every time I soldered on 8v+, the 0v would fall off because the rear pads of the chip both get hot together. Ended up having to use uv cure solder mask to tack down one then do the other one so that even when both went liquid, the one not being worked on was pinned down with mechanical strain relief so it didn't just fly off when things liquefied. So annoying. And I hate to uv solder mask "glue" into place wires that are just there for testing and very temporary ugh... Anyways, its done, no shorts, seems ready for the test now. I did not bother with color coding much as this is extremely temporary for the quick test to ensure everything works.

Note: I think this is the first time I'm showing the rear of the PCB with its exposed major power pads visible and accessible through the viewing window I cut into the bottom of the PCB. These will be where the major power busses attach. These buses will be manually soldered on with thick copper strips I cut from a roll of pure copper sheeting. Those thick buses will also be the start of my thermal conduction pathing to draw heat away from the chip. It has to run 20a continuous so it will get alot of heat that has to wick away.
Adding Landing Pad for Every Unused Pin Of IC
Larry • 08/07/2026 at 06:35 • 0 comments

I was informed that even unused pins on the chip should have copper landing pads to solder to which will even out the forces when the whole pcb goes molten and chip is trying to auto center! It makes sense! So I added those.
Separating Individual Pin Attachments of Left Side Landing Pad
Larry • 08/06/2026 at 23:07 • 0 comments

On the big output landing pad on the left, I separated the attachments to each individual pin for the chip's motor output phase rather than have the landing pad be one big blob. This encourages auto centering. Something I had not considered before until someone pointed it out. Such a simple change but so obvious now that I had it pointed out to me!
Integrated Half Bridge PCB Schematic Revisions
Larry • 08/06/2026 at 00:54 • 0 comments

Here is a revision to my schematics where I run the trace that I had been running under the IC chip instead going around everything to avoid going under the IC chip and the problems that creates. This creative rerouting of that trace also meant I had to get clever with my other traces to compensate and so I had to have one trace jump over another trace at one point and to do this I used a 0 ohm resistor as a jumper bridge to cross over with. In addition to these changes, I also moved the capacitors a bit more away from the chip and eachother to prevent short circuiting from sloppy soldering issues and also just make it easier to work with in general. Also, since the chip had come off the PCB in one corner, I decided I should beef up the number of connections to the chip's outer pads onto my PCB so I added several more attachment points which will help secure the chip to the PCB way better now.
Integrated Half Bridge PCB Repairs
Larry • 08/05/2026 at 10:59 • 0 comments

So the corner of the PCB that peeled back from the chip was a problem I decided not to tackle with a heat gun. I just don't feel too comfortable using a heat gun at this stage. Instead, I decided to remove the capacitor in the way and just hand solder the chip back on. That went smoothly. Problem solved.

That said, to remove the capacitor I envisioned using hot tweezers to grab both sides and lift it off. I did a search online to see if such a device exists and sure enough it does so I bought it! It worked great. A bit pricey at a bit over $100 but worth it. I loved using it to not only remove the capacitors but also to solder them back on in a single motion! Once I get good with this hot tweezers I imagine I'll use it all the time for soldering and desoldering both.

Also the bodge wire I pictured in the last post it turned out involved a bit too much solder on one end which was causing a short circuit bridge between nearby traces so I had to desolder that, remove the capacitor there, remove solder, then resolder it all again. A total pain but no more short circuits. Everything seems good in that department.

Next, I decided that to prevent the flex pcb coming off the IC chip again, I should use UV cure solder mask in a glob as glue to glue the board to the chip to stabilize it and prevent more mishaps. So you can see I did that on both sides and I also used solder mask to glue on the other half of the PCB that we had removed earlier during troubleshooting. So now the whole PCB is in tact again! It is really starting to come along.

Attaching jumper leads to the 6 inputs/outputs to run a full proper test is coming up next.
Attaching SMD Components to BLDC Motor Controller PCB
Larry • 07/23/2026 at 21:59 • 0 comments

I soldered on the rest of the SMD components. I noticed the PCB peeled back off the chip in one corner though so I plan to use kapton tape to tape off everything but that corner, use a couple alligator clips to pinch the PCB onto the chip tightly so it can't move, and then use hot air from a heat gun to reflow that corner so it reattaches to the PCB.

Once that is done, I will attach jumper leads to the 6 inputs/outputs so I can run a full proper test of the whole circuit using a lab power supply and a multimeter.
Testing PCB Using Sewing Needles As My Multimeter Probes
Larry • 07/22/2026 at 18:18 • 0 comments

I wanted to be able to get in there and test this board for shorts and check all traces for continuity with my multimeter but felt its leads were too big for this tiny of a board setup. So I came up with this idea to use alligator jumper cables to attach sewing needles to the multimeter probes thereby making the sewing needles the new probes. This way I could get into the tiniest areas and run the tests I wanted. It worked pretty well! I have now tested everywhere quite thoroughly and everything appears to be in working order. No short circuits and continuity in all the places there should be continuity.

So now I can proceed to running my bodge wire and soldering on the various resistors and capacitors and then running a electrical function test. I will probably use jumpers to the VIN and Vout and GND for this test. Then if it passes the test I can attach the big bus lines which is a bit more involved.
Soldering Chip onto PCB Ran Into Lots of Issues
Larry • 06/16/2026 at 09:58 • 0 comments

Ok so I had multiple failed attempts to solder the chip on. Despite pretinning the PCB, on both attempts when the solder went molten the chip did not center itself and lock into place as would be expected but instead slid out of position significantly both attempts. After the first attempt I assumed it was the outlet bus/landing pad on the left side of the board that was to blame - it being a larger solder mass than the other solder masses on the other edges of the board - causing the chip to slide its way harder and pulling it off center. However, even after cutting off that part of the board entirely and trying again I still had the chip slide out of place during reflow attempt. It's unclear to me the cause of the issue at this point. I put on AMTECH tacky flux that expired in 2022 onto the pcb and then placed the chip as close as I could to centered and then put it onto a hot plate for cooking food or boiling a coffee pot those AC electric hot cooking plates. I had the heat set to max on there. The first time I had the board on the whole heatup time period and watched it gradually smoke off flux vapors and eventually the solder go molten and then I switched off the hotplate but it didn't matter since the chip slid 5mm off center. The second time I added it after plate was much hotter to avoid so much flux burnoff during the heating up process. I also added some flux while it was molten after which time it slid off center. Perhaps that was my mistake? Not sure. In any case, after the failed second attempt I cleaned everything up really well and chose to hand solder it. This seemed to go better. For this process, since both chip and PCB were fully tinned and no shorts to my knowledge, I proceeded to line up the pins the best I could under max magnification and then while pinching it in place I held my solder iron tip onto a trace near a pin for 5-6 seconds to get the solder very hot and hopefully locally heat the whole trace up to and under the IC's pad. I did this for trace after trace. Then to clean up since it was I guess cold joints at this point I applied flux and drag soldered all around every edge. This cleaned up the appearance and got all flux properly seated on traces since it was drifting a bit in the previous step and looking quite sloppy and bad. I did not want to have flux involved during the initial alignment phase and tacking down phases because once that is on I cannot see well the alignment from the sides since the flux blocks my view. Even without the flux its hard to see the traces and their alignment with the pins of the chip. The chip does not have pins is the problem. It has pads on its underside and little pads on its sidewalls. I have to use the sidewall pads as to verify the pads on my pcb line up with those and any flux in the way prevents me from seeing this clearly even with max magnification on my visor.

So anyways yeah, this whole thing was a bit of a disaster but MIGHT have ended ok in the end. For now hand soldering instead of reflow looks like my best bet at least until I can figure out what i'm doing wrong...

Note: I'm not sure if the flux expiration matters I haven't looked into what that means for performance.

Note: I still have no way to verify all joints are good until I test the whole finished PCB I guess. And my confidence they are all good is a bit low. Sucks that I have to invest even more time to finish the PCB while doubtful it will even have reliable connections at present ugh!

Note: I had to remove the trace from the previous post that ran under the chip because during my reflow and cleanup from failed attempts while cleaning some of the solder mask came off and I just wanted to remove that potential short or source of issues as a variable entirely for now. I can always run a bodge wire to reconnect those two points of the board later on.
UV Solder Mask Application Complete
Larry • 06/07/2026 at 21:40 • 0 comments

Ok I managed to apply the UV solder mask today and it seems like it worked quite smoothly. I used the tip of a small sewing needle to spread it over the trace and then held the UV light on it for 10 seconds to play it safe. I used transparent UV solder mask so you can still see the trace but its a bit more murky/cloudy when you see it. I used the tip of an exacto knife to put little scratches on the UV solder mask to test its thickness by feel and test its durability a bit to scratching. And ensure it was fully cured. It was very hard and durable and seems to have gone on fairly thin. The question is, is it too thick/proud of the surface for the soldering on of the chip over it? This is the million dollar question. Because if the mask lifts the chip up off the PCB even a tiny bit then the soldering may not reach between pads on the IC and pads on the PCB, failing to bridge the distance. That is my main concern. If I have any issues with that, I will have to reroute this trace to go around everything rather than on the shortest path like it is now. The shortest path leads it under the IC and led me to have to mask it. Extra steps like this are a bit annoying. I kind of wish I just routed it around everything out of the way more. Then I would not need to UV solder mask at all. Perhaps in a future board iteration I will do this improvement but we'll see. For now I made several boards and want to stick to them since it would be more work to remake them all.
Solder Mask Materials I've Chosen
Larry • 06/03/2026 at 06:10 • 0 comments

Ok so the Relife RL-UVH902 UV fast cure solder mask order has arrived and so has my order for a Relife UV curing light to cure the solder mask quickly and effectively. So now I just need to solder mask off that little trace that goes under the half bridge IC chip.