As an example of recycled parts, here is a push button assemble from an old TV. It even had a plug to suit the hot bed temperature input "J6".
Test code....
#define T_Bed A10 // J16 pin 1
int ButtonPress = 0;
void setup() {
Serial.begin(9600);
}
void loop() {
ButtonPress=analogRead(T_Bed);
Serial.println(ButtonPress);
delay(1000);
}
The values are...
No button = 1023
AV/TV = 953
Menu = 997
V- = 892
V+. = 800
CH- = 560
CH+ = 0
Now I am hunting through my scrapped devices for suitable connectors for the limit switch inputs and the Fan "J10".
I will also be able to install FET "Q13" an the LED connector "J11" to expand the outputs.
There are the un-used U and U2 positions as well as the 6the stepper motor driver poets that I may try for a bit banged I2C port later.