Measure Temperature With the Arduino and the MC9700A

Tim, N9PUZ writes:


A while back you mentioned your club built up some of the bare bones Arduino boards. I’ve been using the Arduino for a while. Recently I needed to measure some temperatures. I discovered the Microchip MCP9700A in a TO-92 package. It’s $0.36 in single pieces from Mouser and will measure -40C to +120C.

I wrote an Arduino library for the MCP9700A sensor that’s released under a GPL license.The library functions will provide either Celsius or Fahrenheit temperatures for as many sensors as you have ADC ports. If anyone is interested they can download a copy from my blog.

There is an installable library, source code, and an example program.


Tim, N9PUZ

Very cool. Thanks, Tim!


  1. Another approach to measuring temperature with the Arduino is to use a Maxim DS18S20 precision 1-Wire thermometer. I’m using this in a project. This device is all digital, no A/D to worry about. You query it and it give you a 9-bit readout of temperature. Plus you can put multiple ones on the same ‘bus’ and read each one individually by querying them. It has higher accuracy and a larger temperature range than the MCP9700A.

    I’ve just starting playing with the Arduino and see lots of potential here. I’m an engineer, but not a programmer (I learned programming in Fortran on punch cards!) but have found the Arduino pretty straight forward to use. How long before we start seeing Arduino projects in QST?


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