ESP32WRM Relay X2 Board Info
This version is built around the ESP32 WROOM 32E chip. It currently only supports Serial configuration but will get an update to allow for Wifi configuration soon. This firmware is what it used in the kits that are available on Tindie and Etsy. If you are trying to recreate that kit yourself, this is the firmware you should start with.
UART cable connection to this board is fairly simple because there is a header that makes it accessible. The pinout order is marked on the bottom of the board which is useful until you have your board in a case where it's not easy or convenient to look at the bottom of the board. The header row is the single one at the center line of the ESP32.
You can make the connection as shown here.
You should not use an external power source with the UART power(+5v)connected. This board can be powered by DC power (5-60V) on listed terminals.
The general recommendation when using an external power source, is to just leave the UART red(5v+) line disconnected. When you power the board this way, there is also a +5V out terminal. Using an external source to power this board is a good option if you have a very low powered PC or SBC as the master for the board or if you also need to power sensors. It is however also very possible to run the board and power the relays(Switching) over the USB/Serial UART connection. It is not recommended to use the 5v terminal to power other sensors unless you are using an external power source and you have left the UART +5v disconnected.
I have had good success using the UART Power to run both dry contact inputs and to drive onboard relays.
In the base firmware 14 IO Points are assigned and ready for use. 4 of these can only be used as inputs, 3 are assigned as outputs. 2 for the on board relays and 1 is mapped to the onboard LED(Also available by pin header)
Pin numbers are marked on the underside of the board.
- [Pin] ---- [S IO] ---- [Type]
- 34 ---- IO 0 ---- Input only (Firmware expects this to be wired as a pull up)
- 35 ---- IO 1 ---- Input only (Firmware expects this to be wired as a pull up)
- 36(svp)- IO 2 ---- Input only (Firmware expects this to be wired as a pull up)
- 39(svn)- IO 3 ---- Input only (Firmware expects this to be wired as a pull up)
- 0 ---- IO 4 ---- Input(must be high on startup) Also wired to button on board for easy firmware upload.
- 5 ---- IO 5 ---- Input
- 12 ---- IO 6 ---- Input
- 13 ---- IO 7 ---- Input
- 14 ---- IO 8 ---- Input
- 33 ---- IO 9 ---- Input
- 25 ---- IO 10 ---- Input
- 16 ---- IO 11 ---- Output(Relay 1 active High)
- 17 ---- IO 12 ---- Output(Relay 2 active High)
- 23 ---- IO 13 ---- Output(Status LED-Active Low)
When looking at the top of the board, it can be disorienting to id the pins. This image should help.
