I am putting together a timer project that use a Teensy 4.1, GPS chip, a couple of DC-DC converters, Lora module, Bluetooth module, RS485 module, thermal printer, WS2812 LEDs, Nextion screen, keypad etc... You may have already noted that I am talking about modules - yes, these are largely discrete subassemblies but I have designed a PCB with EasyEDA to make them easy to connect and added a few things that are at the edge of my electronics comfort zone like protection diodes, voltage divider for voltage monitoring, external pullups for some inputs etc however I'm at the point where there are some things I suspect I just don't know how to add.
- Undervolt lockout of even trying to power up the 9V printer (if powered on by USB)
- optoisolated inputs for the timing beam inputs
- proper ground plane (I don't know anything about it)
- Correct choice of pullup/down resistors for inputs - how can I make the inputs less susceptible to phantom inputs that I think I am seeing (2 HW pin interrupts fire OCCASIONALLY when only one of the buttons is pressed etc).
Rather than try to solve all of these myself, I wondered if there are people or services that could review my design in EasyEDA directly for clangers of mistakes? I'm not expecting this to be free!!!
If anyone is aware of such a service, I'd love to hear about experiences, or if this is even a reasonable request given the reviewer may not be away of the full functional requirements.
I have attached a pic of the board (working fine except for very occasional phantom inputs) to give an idea of complexity.
Cheers - NeilG
- Undervolt lockout of even trying to power up the 9V printer (if powered on by USB)
- optoisolated inputs for the timing beam inputs
- proper ground plane (I don't know anything about it)
- Correct choice of pullup/down resistors for inputs - how can I make the inputs less susceptible to phantom inputs that I think I am seeing (2 HW pin interrupts fire OCCASIONALLY when only one of the buttons is pressed etc).
Rather than try to solve all of these myself, I wondered if there are people or services that could review my design in EasyEDA directly for clangers of mistakes? I'm not expecting this to be free!!!
If anyone is aware of such a service, I'd love to hear about experiences, or if this is even a reasonable request given the reviewer may not be away of the full functional requirements.
I have attached a pic of the board (working fine except for very occasional phantom inputs) to give an idea of complexity.
Cheers - NeilG