Hi There guys, im stuck with something and hope someone can help with this.
I bought a 3d printer without a heat bed and i wanted to add one to it but the pcb board does not have a temp control input or output for the heat bed. So, i bought a seperate 3D Printer PCB Heat bed MK II from ebay and a 100K ohm EPCOS B57560G104F NTC Thermistor that sits in the middle of the board to measure the temperature and a 12v power supply seperate, but nowhere to plug it in to control the temp of the bed.
Is there a way i can connect the 100k theremister to a arduino uno board somehow that will control the power supply aswel.
Using an arduino.
from arduino 5V --> 100k resistor -->analogpin --> 100K NTC -> GND
This will give a voltage (<2.5V)to read with analogRead(..)
Use this value to switch power to heater on/off.
Switching 12V needs a transitor (logic gate MOSFET og NPN switch transistor) and a couple of resistors.
..then goes some lines of software
You should probably add about 10nF or 100nF of capacitance between the analog pin and
ground as the source impedance of the thermistor/resistor combination is well
above 10k, this will make the analog readings more precise and less noisy.
The normal way to control temperature is with a PID controller doing the feedback,
although a very simple thermostat arrangement will work, a PID loop can get much
more stable control. The more intimately you can thermally connect the sensor to
the heating plate the easier it will be to control.