Controlling 9 TEC (Peltier device) with a shield ?

Hi all,
I'm working on a project that requires me to controle the temperature of 9 TEC ( Peltier device ) depending on various parameters.
Overall, I need to control those 9 TEC and retrieve data from around 15 sensors.
Each TEC needs at its peak a current of around 0.3A and a tension of 3V . I was planning on buying a mega Arduino 2560 and a shield like this one (SparkFun Power Driver Shield Kit - DEV-10618 - SparkFun Electronics) but I have several questions :

  1. Are there any affordable shield that provides 9 PWM output ?

  2. I need the PWM frequency to be above 300HZ. I think it is the case for the Arduino , is it still the case for the shield ?

  3. Is the 2560 the best arduino for what I'm planning ?

Any help is welcomed
Thanks

NB: I'm pretty new to electronics and not a native English speaker so sorry if parts of this post aren't as clear as they should be.

Assuming you are a german fellow, the english word for "Spannung" is "voltage" :slight_smile:

0.3A/3V seems pretty low for a peltier, can you confirm that?

  1. The Arduino Mega 2560 comes with 15 PWM Pins, all you need is one transistor+base resistor or MosFET + discharge resistor for each peltier element.
  2. The standard pwm frequency is at least 490Hz (possibly higher, depending on the pin used)
  3. It's a good choice, I would say.

lg, couka

Thanks for the quick answer.
0.3A/3V is indeed pretty low but it's working well so far so I'll stick with those values.
But I still have some questions : I need to control each TEC's voltage and I also need to reverse their polarity at a point.
Can I use the following circuit for each PWM output ?
I put a MosFET // a resistor and connect the output of the MosFET to an H bridge in which there will be my TEC.
The 9 MosFET would be connected to the same generator which can supply 3A/10V.

NB: I'm not that far from Germany but I'm actually not a German.

Einser8:
Thanks for the quick answer.
0.3A/3V is indeed pretty low but it's working well so far so I'll stick with those values.
But I still have some questions : I need to control each TEC's voltage and I also need to reverse their polarity at a point.

Then you need an H-bridge shield, also known as a motor shield. The Adafruit one will probably do exactly what you want - you can stack quite a lot of them together. I haven't looked at its minimum voltage - 3V is very low for motors - but I expect it will work. You don't have to keep the voltage that low - use double voltage and never exceed 50% PWM.

You do not need to use a MOSFET with an H-bridge. The H-bridge will be controlled directly by Arduino outputs.

Please post a link to a data sheet for the Peltier modules -- it is very hard to believe that voltage/current rating.

.http://www.produktinfo.conrad.com/datenblaetter/1300000-1399999/001389163-da-01-en-PELTIER_MODUL_30X30X4MM_TES1_127025.pdf
With Th=25 and deltaT=15, the TEC needs roughly 3V/0.3A. If necessary, I can use it with a higher deltaT/voltage but I'd like to stay at a pretty low voltage.

MorganS:
Then you need an H-bridge shield, also known as a motor shield. The Adafruit one will probably do exactly what you want - you can stack quite a lot of them together. I haven't looked at its minimum voltage - 3V is very low for motors - but I expect it will work. You don't have to keep the voltage that low - use double voltage and never exceed 50% PWM.

So in order to control 9 TEC , I need to get 3 of these shields. I stack them and supply each of them with my 10V/3A generator then plug 4 TEC on each of them and that's it : the shield takes care of the rest ?
That's seems a good solution but on the documentation of those shields,it's written that the minimum voltage is 3V , is there any way of getting below this value because I need to increase slowly the voltage from 0V to a certain value , so far 3V was enough most of the time.
Last but not least, is this the cheapest solution ? Because 75€ on shields is a bit more than what I was planning : Perhaps, I could only buy 2 of them and make a single H bridge myself for the last TEC. Also is a Mega still necessary if I'm using those shields ?

Why are you using 9 TECs, stacked?

Post a diagram showing how you propose them to be wired. 4 does not divide into 9 evenly.

Einser8:
.
That's seems a good solution but on the documentation of those shields,it's written that the minimum voltage is 3V , is there any way of getting below this value because I need to increase slowly the voltage from 0V to a certain value , so far 3V was enough most of the time.

Well that is precisely the point of using the motor shield. It will throttle down the power supply to whatever you want.

Last but not least, is this the cheapest solution ? Because 75€ on shields is a bit more than what I was planning : Perhaps, I could only buy 2 of them and make a single H bridge myself for the last TEC. Also is a Mega still necessary if I'm using those shields ?

There may be cheaper solutions but you would end up spending more money as you explored different alternatives before finding the cheapest.
It does seem excessive to only use one output on the last shield but having them all work the same is valuable. You may find other uses for the spare outputs. Flash a LED or operate the main power relay.