I know this project is a long way from completion anyway and I would surely have to modify things significantly anyway, and swapping one connector for another isn’t too hard on the pcb level. However if I may respectfully disagree with Rungers notes regarding connectors, I am sure it is sound from an engineering standpoint, but as a user with little $, connectors of even slightly sophisticated nature, and especially any significant variety, is a real bother. The lepton 2.0 for instance, the connectors used the picoblade, iirc, did cause significant turbulence. And the thing is I believe these types of complications multiply by each other, rather than being merely additive. So things get out of hand really fast.
It may seem like just another drop in the bucket to use a more advanced and slightly less common connector, but imo it is one thing that can be trimmed back. IMO 2.54 mm through holes are the winner in this case. However there is clearly a lot else to do here and it would make no sense to get bogged down in connector selection and frankly I don’t even know what most of the connectors Runger mentioned are.
But if you recall we had problems with the Picoblade, they pre-made connectors are ridiculously overpriced, like $10 each. For all 4 connections on the lepton it would have been $40 to buy them from digikey. By mere coincidence there are little kits on amazon that you can use to assemble a ton of connectors yourself from pre crimped wires, but it was touch and go and hard to discover that option. That was a close shave.
I agree, 2.54mm is the most convenient. I can still crimp 2mm, but below it’s a gamble if the crimp holds. Premade cables typically are too long, too short or need to be converted to other connectors, they hardly ever fit my needs.
Both the Picoblade and JST SH type connectors are very commonly used, with many alternative vendors that provide fitting plugs and sockets.
For this reason there are also vendors on AliExpress that provide pre-crimped cables of various lengths and types, for very cheap eg <$1 in quantities of 10 or more.
Of course blank headers are cheaper still, but that means soldering for the user, and a big additional source of error.
I agree that self-crimping these sizes isn’t easy, but premade cables are available. Having a connector rather than just a DIY header makes the board much more finished and easy to use IMHO.
Of course, useablity always has a certain price, so it’s a trade-off.
I thought picoblade was copyrighted or something? I probably didn’t check aliexpress because I needed them fast. I do recall complaining that digikey can’t just stock stuff at reasonable prices. The idea of a one stop electronics store seems to have escaped them. If people can offer something on aliexpress for $1, you should be able to buy ten of them from digikey for $20.
For the 1.25mm pico blade connectors there is an equivalent JST part, but also other vendors. I don’t know how licensing for those things works, or if the patents have expired, or the connectors are in some non-essential way “different” and hence compatible but not the same.
Anyway, I don’t think it matters. The important thing for me is that there are people selling cables for them
Hi @Matt303 ,
Thank you for sharing this OPAmp setup.
I know you were planning to work on this board. Just checking to see if it this setup worked out for you (for the higher volt and current requirements)?
I’m trying to do something similar (based off of the STM32G431CBU6 version, similar to the B-G431-ESC1. But not sure on what resistors to choose for the OPAmp network.
Can you please share how you were able to find the value of the internal feedback resistors R5(2.7k) and R4(1k), as the gain is primarily dependent on these.
