My response from Apr 22nd…
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Sweet, will it have support for a power button?
You don’t want to use current filters on a low side shunt design.
The phase voltage filters are a good idea though.
The sampling data looks pretty noisy. There is a similar issue with the 75200 and it caused a lot of problems running motors smoothly.
4 layers instead of 2 layers would probably help a lot by having ground planes close to the signal lines for a short current return path.
Cool to see the progress on this project!
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Hey, Thanks… I got it wrong here.
And thanks for the link. I think it will help me a lot. If you have more - just feed it to me.
Yeah, why not. It’s on the list now. Thanks
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How many Layers?
Currently, the board has only two layers, and the dimensions are 90mm x 62mm, which is 5580mm².
Some simple math on pcb board prices from JLCPCB:
2 layers: 1$ per 5000mm²
4 layers: 1$ per 1250mm²
This means that the price for 1 board is: (yeah, obviously without components…)
2 layers: $1,12
4 layers: $4.46
That is additional $3.34 for a 4-layer layout. I don’t think it’s a lot, considering how crazy the price of an original vesc board is these days.
Well, what do you think?
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OPENAI: PCB boards: 2 layer vs 4 layer?
When designing a printed circuit board (PCB), one of the decisions that needs to be made is the number of layers to use. The most common options are two-layer and four-layer boards.
Two-layer PCBs are the most basic and affordable option. They have a layer for components and traces on the top and a layer for traces on the bottom. This type of board is suitable for simple circuits, and the routing can be done manually.
Four-layer PCBs have two additional internal layers for routing, providing more space for components and reducing electromagnetic interference. They are more expensive to manufacture than two-layer boards, but they offer better signal integrity and can support more complex designs.
In general, if you have a relatively simple design with few components and traces, a two-layer board should suffice. However, if you have a more complex design that requires high-speed signals or high-density components, a four-layer board is usually a better choice. The additional layers can help reduce signal noise, shorten signal paths, and improve the overall performance of the circuit.
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Most of the money is gonna go on components, so if you keep most (ideally, all) on one side and can improve signal integrity by going to 4 layers, go ahead!
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I think 3 usd difference is not much, if it improves the routing and signal quality, especially considering the price of mosfets, etc… How much is the current bom cost?
Edit: If the power button is possible, this would be ideal for onewheel conversions. I think I could even build a batch of them and assemble boxes for people, since there would be no supply chain issues. Sweet!
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What are the main differences when comparing Cheap FOCer?
So I ordered the updated board at JLCPCB with “basic” components assembled by JLCPCB. The “extended” parts I will solder myself.
So without jst-connectors the price of components on 1 board is $22.35
(If ordering in larger batches, there will be discounts. Here the batch size is only 2)
The price includes both “basic” and “extended” components, and mosfets.
It better work…
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Cheaper, simpler and better, in terms of voltage, amps and HFI.
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Can I make a suggestion/request…
One thing that’s super helpful is to keep the very first post updated with the basic specs (e.g. how much voltage and current this can handle), expected cost of BOM, and link to the latest documentation.
Great stuff. Thanks!
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It looks like I spoke too soon. I see that you have a link to the docs, and the docs have a nice readme.md file. The only (tiny) nit, is that you link to docs that link to a new set of docs. You might update the top post to link directly to the current docs - but now I’m just looking for things to whine about. 
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I’m WAY behind on this, so my apologies if some of this has been addressed.
I love the fact that JLCPCB will populate their components, but that doesn’t address the issue of replacing a fine pitch component. Personally I’d love to see it use something with a somewhat larger pitch. But it’s certainly not a deal breaker.
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