Choosing the right components for a small project


I'm new to arduino and would therefore like some help to choose the right components, software etc. for getting started with a small project i have in mind.

Comming from the industrial automation branche, i have worked a lot with programming of PLC's and HMI panels, but this project is so simple that implementing a PLC would be overkill in my opinion. Besides, i suspect that the Arduino will be able to to excatly the some job as the PLC for 1/10th of the price..... And it looks more fun.

So here's what i need on the control board:

12 V DC supply. I will have 12 V DC available in the control cabinet already. Is it possible to power up an arduino with 12 V?

2 temperature sensor inputs. Preferably for the input signal of PT100 sensors as these are eaisliy available in the form of a stainless steel cartridge with a silicone cable firmly attached to it (mechanically strong).

2 digital outputs for controlling external solid state relays intended for driving two Peltier thermoelectric coolers.

A nice illustrative touch screen of some kind, able to show a temperature curve according to the input of the two temperature sensor inputs. I believe Arduino has got allready available touch screens in sizes of 2,4" and 3,6", correct? Otherwise, a tablet could perhaps be used by connecting via WiFi to the arduino??

Software for aduino and screen, programming cables, connections between screen and main bord etc. All the other stuff for making thing work. What will i need?

The point in this project is to make an accurate temperature controller. A Peltier is cooling down a subject. A temperaturesensor is monitoring the actual temperature at the subject. Once the subject has reached the desired setpoint (chosen by the operator on the screen), the peltier will turn of. Working either as a simple thermostat or a more complex PID controller, the arduino should be able to hold the subject at a given temperature and show the actual temperature in degrees C on the screen together with the desired setpoint which can be altered on the screen. The second temperature sensor will be used for drawing af curve of the change in temperature during time in another subject.

Best regards


Start your project simple and add bits as you get the earlier parts working.

Work out your basic temp sensor read and turning on/off the outputs depending on the sensor. Add bells and whistles as you become more familiar.

The drawing on the LCD will be another thing altogether. You will need to go give the data of the LCD if you want any help.

The 12v will be suitable but don't try to run too much off the 5v or the regulator will over heat.


PT100 sensors typically need an op amp input before the Ardunio, for simplicity you could use a D18B20 , metal cased type, which connect direct and have many ready made library code examples.

For a touch TFT screen, again , typically they need a Mega2560 to drive them, 1, because most are parallel driven and need a lot of i/o pins 2. The program code needs a large memory and the power of a mega2560 chip over the smaller devices like the Uno /mega328.

As well as DS18B20 libraries there are also PID examples on the Arduino site if you really need to go that route.

Hi, Sounds like a machine for checking chocolate tempering characteristics.

Tom... :)

weedpharma: The 12v will be suitable...

.... as long as it's regulated and isn't actually higher than that since 12V is the upper limit of the recommended input voltage.