ESP32 Forum

I have just bought a motherboard from eBay for use with the esp32cam to see what they are (search eBay for esp32cam-mb).
It seems to work well as long as I set the upload speed to the slower options (e.g. 115200) but the reset pin is very interesting, it
works by linking together the gnd pin next to 5v with the gnd pin next to the tx/rx pins, this only works on the esp32cam module which was supplied with the motherboard (when checked with a multi-meter there is no link between them in the esp32cam).
Does anyone know if this a new standard feature or is it something created specifically for use with these motherboards? I can't seem to find any information on them.

It seems that the gnd next to the 5v pin is still ground but the other has been made in to a reset pin on these boards?

btw-I can still use it with my other esp32cam modules but I have to hold the program button whilst connecting the USB to upload sketches
I find the wifi signal very weak whilst attached to the motherboard although I have discovered if I hold a finger above the antenna it then work ok. The esp32cams seem very sensitive to anything being near their antenna and I guess this is why many of these motherboards are sold along with an external antenna.

Please post pictures / link to the 'motherboard' in question ?

Agree007 wrote: ↑

Fri Dec 18, 2020 11:26 pm

Please post pictures / link to the 'motherboard' in question ?

This is the only info. I have managed to find about it, which is very little
http://www.hpcba.com/en/latest/source/D ... AM-MB.html

This is a typical listing on ebay
https://www.ebay.co.uk/itm/ESP32-CAM-WI ... Sw9rJfqsqv

If they don't provide any schematic you'll have to reverse engineer it, follow the traces on the pcb. Can you take some high res photos of this other GND pin you're curious about, both sides of the board, and see what it connects to?
If they're both labeled GND but not connected that sounds bad to me, sloppy design or mislabeled.

becorey wrote: ↑

Sat Dec 19, 2020 5:37 am

If they don't provide any schematic you'll have to reverse engineer it, follow the traces on the pcb. Can you take some high res photos of this other GND pin you're curious about, both sides of the board, and see what it connects to?
If they're both labeled GND but not connected that sounds bad to me, sloppy design or mislabeled.

hi,

I have followed the traces and when the reset button is pressed it links the two ground pins, the one next to 5v already being linked to ground. i.e. the other gnd pin seems to have been changed to a reset when low pin.

I agree that it is mislabelled and seems to be none standard, poor practice etc. but on the other hand it does seem a good idea as when in the motherboard it makes using these esp32cam modules much easier / more convenient. i.e. You can easily program them just like any other esp32 development board rather than have to use an in circuit programmer, link pins while resetting it etc.

I had already order one , should arrive next week or so, then i can check and play with it.

So the GND next to tx rx is probably mislabeled and actually the EN / CHIP_PU pin. There's nothing special about that, EN is usually broken out to allow you to control the module power up. Every esp32 dev board is like this