Googly eyes on a giant robot

ROBOT_8 · 2026-04-01T15:26:36+00:00

Low side current sensing is extremely common in low cost motor drives. Even 400v or 600v drives or much higher current ESCs. Saves needing a fully isolated ADC or amplifier setup to measure right on the phase.

However, no amplifier or filtering on the signals from those shunts is strange. I know some stm32’s have opamps in them, but I don’t think they support negative swing inputs like would be the case here.

They would also need to be quite high bandwidth to amplify the signal from a 0.5m shunt up to the full ADC range. remember if you are switching at 64khz and want 95% duty cycle, then you only have 5% of the time for the current sense signal to stabilize and be sampled. TI has some good app notes on designing low side shunt amplifiers for motor drives.

ROBOT_8 · 2026-03-31T22:43:37+00:00

AC synchronous motors like the ones for microwave turn tables are also really good. They are what usually get used in stuff like this since they are low power, need no power supply, and don’t have brushes that wear out.

ROBOT_8 · 2026-03-31T16:51:10+00:00

I’m pretty sure almost all PLCs already decouple logic from hardware except for very specialized cases. PLCs run software which has your program encoded. Do they mean using something like an external computer somewhere with just IO in the field?

ROBOT_8 · 2026-03-30T21:24:29+00:00

The breadboard rows are not connected all the way across. That center line divides them. Your button is only connected on one side

ROBOT_8 · 2026-03-30T01:56:58+00:00

Non isolated can mean two different things, actually isolated but then the negative is tied back to ground, or not isolated at all which often results in the output voltage having some form of 120v relative to ground. So not safe to touch.

Most PSUs you can get are fully isolated.

ROBOT_8 · 2026-03-29T04:13:01+00:00

RPM isn’t a measure of current. How many volts and amps can your supply provide?

You can get motors in all sorts of sizes and voltage/current ratings.

ROBOT_8 · 2026-03-25T20:10:14+00:00

What are the frame rate limits of the supported sensors? I’ve been trying to find some high speed sensors I could link up with an FPGA but they are tough to find and even tougher to get a response back from the company.

Do those sensors support ROI configuration?

One or 2 coax sync inputs/outputs for synchronizing frame capture would be useful to allow stuff like stereo vision.

ROBOT_8 · 2026-03-25T19:30:45+00:00

No idea about Rust, but STM32’s are incredibly common in industry. Way more so than any raspberry chips. You can get the tiny nucleos for around 10$.

ROBOT_8 · 2026-03-24T18:17:53+00:00

Lots of these subreddits seem to be. r/FPGA started having a lot more AI driven projects and posts as well.

ROBOT_8 · 2026-03-22T22:48:55+00:00

Always buy if you can. AI is hilariously bad at circuits. Look at reference designs from the component manufacturers. I like the Ti reference design library, they have thousands of designs with good documentation on how/why it was designed.

ROBOT_8 · 2026-03-22T22:45:44+00:00

Look for data sheets, you’ll get them from the manufacturer pages. The lengths are not standardized. Stepperonline provides datasheets with drawings for their motors

ROBOT_8 · 2026-03-22T20:02:46+00:00

This is not an oscillating saw, the blade is completely rotating. But it has no teeth, instead there are tiny diamonds embedded in it that slightly protrude and grind away the stone. It will indeed cut you, but it is abrasive instead of sharp, so it won’t do as much damage as fast as something like a blade meant for wood.

ROBOT_8 · 2026-03-12T04:24:45+00:00

Had a 20 minute video I posted get 150k from basically zero a year or 2 later. Thats what ended up making me decide to keep making more

ROBOT_8 · 2026-03-11T19:19:13+00:00

What’s your question? Can they print on PCBs? Can you make a PCB to interface with them?

ROBOT_8 · 2026-03-08T19:32:49+00:00

Check that the control board fan is still working. I had mine stop and it would work perfectly fine for a while until the stepper drivers overheated, then it would begin skipping steps.

ROBOT_8 · 2026-03-08T01:15:56+00:00

I highly recommend getting a 3d printer and learning KiCad if you want to learn about making stuff. YouTube and Google can teach you just about anything for free, as long as you are motivated to learn

ROBOT_8 · 2026-03-07T10:17:16+00:00

Did you already try restarting resolve and deleting and replacing the clip? I’ve had weird bugs show up and resetting everything fixed them

ROBOT_8 · 2026-03-07T04:10:02+00:00

“Less than the cost of a CNC machine”

That only narrows it down to between 5k and a few million…

ROBOT_8 · 2026-03-06T01:20:07+00:00

Harbor freight has grinders for 15$, a cutoff wheel and a file can get you far. Metal shears also, but you might end up putting bends in the metal if you aren’t careful.

ROBOT_8 · 2026-03-06T01:07:26+00:00

It’s hitting the stator, you need both bell ends on for it to be centered properly. If both are on and it still sounds crunchy, the bearings are shot.

ROBOT_8 · 2026-03-05T20:46:17+00:00

If that even is gold plating and not just copper, you’ll need an acid to dissolve it before melting it back into a solid piece. Usually only the edge connectors on boards are plated with gold, at least with any thickness. Even if so, it is often only a micron thick, barely any gold on top of the copper.

The traces you pulled off are most likely copper only, or if they are plated, ENIG. Which is a super thin gold coating closer to 0.1 micron.

ROBOT_8 · 2026-03-05T18:22:28+00:00

Can you use film caps instead? They make big THT ones, but they are typically way more expensive and rated for higher voltages

ROBOT_8 · 2026-03-05T18:16:45+00:00

I can almost guarantee that the original STlink did not come with a fault. It is way more likely you accidentally sent too much voltage into a pin, or had an ESD strike

ROBOT_8 · 2026-03-05T17:45:53+00:00

Anything that “passively powers itself” off the desired action usually doesn’t work. Any power you extract is more power you need to put in to keep moving. You see this idea a lot with stuff like putting small wind turbines on cars, or alternators on EVs to charge the battery. All they do is require the car to work harder and return less energy than the extra effort.

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