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ESP32WRM Relay X4 Board Info

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JCsGotThis edited this page Apr 5, 2024 · 3 revisions

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. The only real difference between this one and the X2 is the number of relays and the number of IO setup for general use.

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.ESP32WMR Relay x4 UART Connection with +5v

You should not use an external power source with the UART power(+5v)connected. There are 2 ways to apply external power to this board. AC line power(90-220) and DC power (7-30V). This is a good option if you have a very low powered PC or SBC as the master for the board. It is however also very possible to run the board and power the relays(Switching) over the USB/Serial UART connection.

You should not use the UART Cable power to supply power to any sensors or devices. It could damage your PC or SBC. I have had good success using the UART Power to run both dry contact inputs and to drive onboard relays.

The general recommendation when using an external power source, is to just leave the red(5v+) line disconnected.

Board IO assignments

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 ---- general IO Important note.. Will output a PWM signal on boot. Should not have any affect if configured as an input.
  • 12 ---- IO 6 ---- general IO Important note.. boot will fail if this is pulled high during boot.
  • 13 ---- IO 7 ---- general IO touch capable
  • 14 ---- IO 8 ---- general IO Important note.. Will output a PWM signal on boot. Should not have any affect if configured as an input.
  • 16 ---- IO 9 ---- general IO (RXD 2)
  • 17 ---- IO 10 ---- general IO (TXD 2)
  • 26 ---- IO 11 ---- Output(Relay 1 active High)
  • 25 ---- IO 12 ---- Output(Relay 2 active High)
  • 33 ---- IO 13 ---- Output(Relay 3 active High)
  • 32 ---- IO 14 ---- Output(Relay 4 active High)
  • 23 ---- IO 15 ---- Output(Status LED-Active Low)
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