Working on it. Some problems with the first board - not sure, but phase 3 current sensor seems to be offset a lot to the negative. Trying to figure it out - maybe I need to assemble board 2 to see if the problem is still phase 3.
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Having problems with current sensing - think I have run in to a good old “ground bounce”. Another board’s coming up, with modifications to avoid this. If you don’t try stuff sometimes you don’t learn. Now, hopefully I have learned…
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Updates checked in on github… Still didn’t order updated board yet - still need to add a few details.
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Suspecting that the 8 mhz crystal is a source of noise on phase 3. Had the opportunity to play with an original vesc today (vesc6 75V-60A). Rather unexpected it seems to also have the most amount of noise on phase 3 - can anyone else confirm this pattern?
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Some of you might find it strange that each time I order an updated board from jlcpcb, it seems to be a complete redesign. And yes, here is another redesign.
Why this configuration:
- It is expensive to order a new board each time there is a small update - so having an arduino-like attachment board saves me money.
- This configuration allows for more applications of the hardware. It is now not only VESC compatible, but also compatible with MESC firmware - made by David Molony (aka MxLemming). Using MESC firmware, the break-off default stm32f405 “pill” can be replaced with both BlackPill and BluePill (very cheap), etc. Potentially, it can be made compatible with SimleFoc using an Arduino.
- As some of you might know, the Vesc Firmware is VERY restrictive, and it’s basically impossible to make any commercial product using this firmware, which is actually what I would like to do. - A wind turbine. These restrictions are not in favour of the Vesc project in the long run - I’m afraid. So compatibility of hardware is important, in my opinion.
I have removed the IMU temporarily, but it will be back soon. Still CAN is there…
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This is amazing, the BoM cost on one hand, but also the supply chain independence of a commodity item available in endless supply.
I fear the scope creep of venturing away from VESC (the goliath that it is), but you’re breaking through the issues as they come up, so I don’t think I feel the need to dissuade you from reaching beyond VESC
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I think I must be going to the wrong repository. I went to the github link in post #1 of this thread, and it redirected me to…
But that isn’t showing me any boards like the pics you have below.
By the way, I personally very much like the arduino-like daughter board.
My fault. I just updated github NOW.
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Doubled the number of mosfets, added IMU again and made power supply a separate addon. And some fixed issue. Now I’m back to a more traditional style FOC board - no more fooling around with alternative ways of mounting mosfets.
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5 complete boards (excl mosfets), $88.-
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Is it safe-ish to order now? I am gonna need a lot of controllers for a robot arm project soon, but getting off the shelf vescs or odrives is way out of the budget at this point.
Does the power supply addon get mounted to the main board? I don’t see where it goes. Or does it become a free-floating board of its own?
And why is it separated?
Thanks.
Not safe to order. I’m sorry, but it just takes time when you start from scratch and have to go through a lot of (now obvious) mistakes. I hope the current jlcpcb order, which I will receive in a few days, will work in a way worthy of a demo video.
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The combined 12V and 5V power supply is going to be mounted on the front side of the board (just below the gate drivers (where you see the six pins - although you should be able to solder it on even without pins). The reason is to make the board modular, which means that for a double vesc board you only need a single power supply.
The small stm32-MCU-board is to be soldered to the back side of the main board, where the mcu-board itself is turned around so the MCU is facing downwards. In this way you don’t need pins for soldering it to the main board.
The modules should also make it easier for “the public” to understand how the board works, because everything is seperated in:
- An arduino-like MCU board
- Power Supply (12V, 5V)
- Driver board (everything having to do with mosfets, driving of mosfets, current sampling, shunt resistors, Operational Amplifiers, voltage sampling, and CAN bus)
Finally:
- Development is much cheaper, because you often only need to re-order specific modules in the development process.
- Repairs are cheaper and easier, because it’s easy to identify which module is failing, and you only need to reorder that specific module.
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I love everything about that! The one request I’d make is to consider breaking out the discreet FET drivers onto a daughter board as well. The things I’ve seen fail are: FETs, the microprocessor, and the DRV IC.
Perhaps with discreet components the FET driving circuit will be more robust?
I just really like the idea of being able to swap things like this for debugging and repair.
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And I’m sorry about the amount of time this takes, but we used to be waiting for the Cheap Focer 3 - I did that for 6 months, until I realised that the guy was a fake, and had to take on the development myself.
Dickhead take
I really don’t think Shaman is a fake. He has put out several designs, and I’ve built some of them myself. I will confess that the wait has been long for the CFOC3, but it’s hard to blame someone that has a day job for not doing my free pet project fast enough.
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Yes, I have thought about this too. Haven’t settled on whether the main board should be (or can be) further decomposed.
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