Hi guys, I’m new to all this so please bear with me.
I have a spark core and would like to use its WIFI capabilities to automatically adjust the temperature of a Peltier unit attached to a heat sink and fan. I’d also like to have an led showing the ranges of temperature but that doesn’t seem as complex.
How do I go about purchasing the correct Peltier unit and what accessories would I require, in order to get this working? The Spark from what I can see can run off a max of 6v, does that mean I can’t use a 12v fan with it?
I assume you want to cool (or heat) something with your Peltier device. A Peltier device is a high-current load so you will need some external circuitry for it.
You will need a high wattage 12V power supply and either a separate power supply for your Spark or buck converter since it needs +5V or +3.3V. An old PC power supply would do nicely, for instance, but there are lots of choices.
You will also need a high-current switching device like a power transistor or a MOSFET to control the Peltier device. Here is an Arduino example:
You need to make sure the grounds of the two power supplies are tied together but you can’t let the +12V get to core or you will fry it.
Finally for the control loop, you will want a temperature sensor like a DS18B20 or a 10k thermistor or a TMP36-type sensor. Just stay away from 100k nominal thermistors since they require more external circuitry on Spark.
The SparkCore (and most other microcontrollers) can only directly control LOW POWER peripherals. You will therefor need something to control the power going to the Peltier device (you also will need a power supply). You have many options. I would start your adventure with a google search for “Relay”, “Transistor”, and “Mosfet”. You will need one of those to control the power going to your device. Next you will need something for temperature measurement. I would suggest a digital sensor like a DS18B20 since it’s easy to interface with and you don’t have to work about calibrating it. Finally you need some kind of LED display. I would probably pick up a cheap 2x16 LCD display from Adafruit or Sparkfun and start with that.
So to recap, you need:
A power supply which can supply 12v and 5v. A computer PSU will do this for you or you can find a 12v supply and further regulate to 5v
A electrical “switch” like a transistor, mosfet, or relay to turn power to the peltier on and off
Thank you for the help guys. Unfortunately the Spark Core has been acting up for almost two weeks worth of trouble shooting so it’s being sent back to the supplier for a refund. I’m going with an Etherten freetronics board instead, which is essentially an arduino uno. Really appreciate the direction you gave me though, both of you.
No they couldn’t have. The core was faulty, wouldn’t connect to any of the wireless networks I took it to (four) and wouldn’t connect via the USB process either… It was just one of those unfortunate occurrences that can happen in life, oh well.
Have you sent the core back yet? I’m curious what troubleshoot steps you have tried to fix the problem. A “my core won’t connect to WiFi networks” is not a completely uncommon error and I would say about 1/ 2 the time you can fix it with a software change. Sometimes they are indeed faulty but not always. Have you sent hello@spark.io an email explaining the issue? I’d love to help you over there if you are still up for it
