Cheap FOCer! (VESC compatible 4.12 redesign) (Tested and Functional)

i always use the achmaniac firmware

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I’d be in for a “assemble it yourself” kit if that’s even a possibility?

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I’ll hold my hands up. I’ve been hopeless. Planning on changing that.

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Not for the Cheap FOCer. However, you can buy the parts to assemble yourself with the BOM and Gerbers from the GitHub. I’ll update the Gerbers for v1.0 whenever that happens.

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Me too. I just tried a full implementation of VESC formate with NRF and found the detected settings from the wizard to be very strange, dangerous even. Plus the lack of ERPM regulated direction switch caused me to re-evaluate the decision. I guess it only works well on VESC hardware.

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I think Frank said to use the advanced view to get back all the doodads

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I’ll check that out. Ty

Finnaly got all the parts and started the build.

It all went pretty well and i was able to compile and flash the firmware and bootloader to the stm chip.

I checked for shorts between the power rails and connected it to a 19V power supply. It pulls around 300mA but did not power on. When i checked, there was only ~1.8V on the 5V rail. So its probably something with the DRV chip.

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The controller should only pull around 40mA on standby. Sounds like something is shorted on the 5V rail. Do a continuity check or resistance check on 5V to ground while unpowered. Also make sure the ST link V2 is NOT connected to power when powering up the controller.

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I would also advise using fw versions 3.4x for now. There seems to be issues with fw 3.5 and above with the Cheap FOCer

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Thank you shaman, i get around 19kOhm between GND and 5V…

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Seems like that is ok. Try the same for 3V to ground. If that checks out, then lets double check the DRV for solder bridges. Also, find what’s getting hot when you give the controller power. That will be a clue as well.

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good to see people building

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Yeah really good to see some more in wild. I hope one day I can come back from the point I got stopped testing mine. Really want to try what I can get out of them.

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3.3V rail also looks good, >4.4kOhm… Must be something with the DRV, will check for shorts…

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I’ve always wondered why vescs had to be double sided. Good shit dude.

Checked the DRV for shorts, also checked 5V sense voltage divider… it looks ok… i wonder if its maybe something in the DRV buck converter… with the diode checker i get 0.2V with reverse polarity and 1.8V between GND and 5V…

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Can you give it power for a bit and see if something is getting hot?

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sure, i checked the current again now its only pulling 75mA. Still the same 1.8V on the 5v rail…

I probably solder a new one tomorrow because i cant remove the DRV chip from this one.

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Did you solder the ground pad of the DRV? If I remember correctly it’s the only ground reference the DRV has so it needs to be soldered. I think there was a discussion about about using the vias of the pad to solder it further up this thread.

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