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Author Topic: Temperature sensor w/ ssr and thermocouple  (Read 758 times)
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Hello,
I am trying to hook up a temperature sensor:
http://www.dfrobot.com/index.php?route=product/product&product_id=164#.UXazzaVc_ww
to a thermocouple arduino:
http://www.karlssonrobotics.com/shop/thermocouple-amplifier-ad595-aq/?gclid=CJT0woqa4bYCFcuh4AodPWUABw
with a solid state relay:
http://www.aliexpress.com/store/product/Arduino-Compatible-Four-solid-state-relay-control-module/811021_560592500.html

to mimmick this project:
http://playground.arduino.cc/Main/BarebonesPIDForEspresso

however i will not be hooking it up to any coffee machine therefore there will be no thermostat. Do i have the right parts here to make a device that can control a battery pack to turn on and off based on the environment temperature?
Sorry for all of the links but I would really appreciate any help I can get.
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I like lots of links, so that is fine.

The DS18B20 sensor has a digital interface.
It is accurate can be connected to an Arduino pin with the OneWire libary.
http://playground.arduino.cc/Learning/OneWire

A thermocouple is for a thermocouple sensor. For accurate high temperatures or industrial or laboratory applications.
http://en.wikipedia.org/wiki/Thermocouple

The SSR (Solid State Relay) is to switch a mains apparatus.
It can not be used to switch a low voltage DC battery pack.

Take a look at the Adafruit and Sparkfun websites. They have selected products that go well with the Arduino. Adafruit has also many tutorials.
http://adafruit.com/
https://www.sparkfun.com/
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Ok sorry to be asking such elementary questions but my experience in this area is minimal. So from what I got from your response is that I can use the DS18B20 one wire temp. sensor coupled with the arduino. The goal of my project is to control a 9volt battery powering a heating element composed of teflon coated copper wire. I want the temp. sensor to read temperature values in the environment where the heat is being supplied and turn the power source to the heating element on at temperatures below 80 degrees F and shut it off at temperatures above 110 degrees F. It is essentially a thermostat. I am just a little lost trying to bring together all the parts I will need to make this happen.
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The DS18B20 is for measuring the environment temperature (not for furnaces or so).
You need a pull-up resistor, the pictures show how:
http://fritzing.org/projects/arduino-and-ds18b20-temperature-sensore/
http://bildr.org/2011/07/ds18b20-arduino/
You have to install the OneWire library and learn how to use it.

A simpler (but less accurate) solution is the LM35 or TMP36 temperature sensor.
This is a tutorial, http://learn.adafruit.com/tmp36-temperature-sensor
But if the 5V of the Arduino changes, the temperature becomes more inaccurate.
If you use 9V for the Arduino, you can assume the 5V on the Arduino board is good, so the LM35 or TMP36 can be used.
If you use the USB to power the Arduino, the 5V could change.

For a heater, I suggest to use an relay.
How much is the current for the heater ?
To activate the relay you could use a transistor or darlington transistor.
http://www.pighixxx.com/abc-arduino-basic-connections/
"Card3" shows how to connect a relay with a BC337 transistor.
Click on "Set 1 (Card 1,2,3)" to open the pdf.

I'm curious about the battery. What kind of battery is it ?
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