First project button press.

Hello everyone,

Just recently I started to get interested in broad electronics and decided to add wifi feature to my wife's beloved portable oil heater as my first microcontroller project. Long story short I was thinking about using either esp8266 or esp32 to get the job done. After taking the heater apart it turns out that it consists of 2 boards

(a) power board
(b) control board

I will probably use main existing power board to provide power to uno/8266/32.

Control board consists of beep speaker, display and 7 momentary switches (visible here on far left and far right side of the board as well as one on the , for example to the left of R6 & R36 as well around R38 components). Those are standard 4 pole momentary switches, however they are quite weird since they read exactly the same voltage on both ends. Long story short I'm trying to use either nano, some variation os 8266 or 32 to simulate the button presses in order to remotely adjust temperature prior of arrival home or prior of waking up.

It turns out that shortening any of the 4 poles would actually act as a switch press so I was originally leaning towards relays however it seems like relays are more geared towards high voltage applications. So here lies my question, or rather multiple questions

(1) Is shortening the pins using microcontroller the right way of simulating button press on existing appliance with a keypad consisting of momentary switches.

(2) If it is, how to properly execute it without using relays, or maybe relays are the right way to go?

Thank you for your support in advance.


Going straight into the deep end?

I would strongly recommend that you get to know the Arduino world before hacking into an appliance. Buy a sensor kit and experiment. Write some programs. Make your mistakes where it doesn't matter.

Hi, widofmaker.

  1. I mean, buttons basically short their own pins, so...
  2. Depends on the voltage running through the button, but I would personally use relays, just to be on the safe side. You can probably get a relay board like this:

OK, well, those diodes are telling me that the buttons and switches on your board are multiplexed/ matrixed by the microprocessor. Presumably the microprocessor operates on a 5 V supply so if that supply is reference to the earth of the appliance (and if it is not, we recommend you forget your proposed project) then you can operate your ESP8266 module (you did say "WiFi", meaning ESP8266 and not Arduino) from that same supply and use a couple of 74HCT4066 to emulate the buttons.