MK3 ALU Heatbed temperature controler

Hello everyone,

I 've found a similar topic to this one, but as it was older than 120 days, i was suggested to start a new one.

My 3D printer electronics does not allow me to control a heatbed.
So i need a stand alone solution. I’m looking for a cheap solution ofc.
I was suggested to use an arduino board to do so.

I’m totally new at this and don’t own an arduino yet.
A year ago i installed the software and had a quick look at it just out of curiosity.
So before i go and buy one i would really appreciate any advice on this matter.

I’ve got a tiny bit of knowledge about electronics, but really not enough for this.
Searching the net, i found several schematics and used them to make my own.
It is said that it won’t do the trick, cos of lack of reaction time if the temperature drops.
I got some components already. I’ll post my schematic where they all figure instead of listing them up. To read the temperature i bought a LCD Panel With Probe Sensor(i’ll ad the doc here)
The PSU is of a PC (60W).

Would any of you be so kind to help me out with this?


Hi, that circuit will function from what I can see, it PWMs the heater using the thermistor to control the LM555. Many years ago I use a similar circuit to keep a photographic chemical bath temp controlled.

I hope that you are using 0V to 12V, and not -12V to +12V as shown, that means you have 24V powering the LM555. Look up the datasheet it says 18V Max, but I have found even 15V can cause problems, 12V is okay. Placing the two sensors together should give you a nice simple controller.

Tom.... :)

aw man, that's some really good news. I will buy an arduino anyways when i get the money. I think it's worth to be used for better stuff than this. Thx a bunch for the input.


Hi, the circuit on second look, will work, but not using PWM, it will just turn the heater ON when it is too cool and off when the temp is attained.

The arduino will have finer control, but I don't know how precise the control has to be.

Tom.... :) Getting late got to go to bed..


I hope someone drops in for this…