Saturday, November 21, 2009

ARRL Sweepstakes - Phone

Pssst, hey kid... wanna do Worked All States in a weekend? This is Sweepstakes Phone weekend. There will be many, many operators on all trying to make as many phone contacts as possible beginning mid-day Saturday. Hope to put a bunch of you in the logbook!


Tim, N9PUZ

Thursday, November 19, 2009

MCP9700A Temperature Sensor Arduino Library

I've done a little polishing on my code for using the Microchip MCP9700A Temperature Sensor and converted it to a library for the Arduino. I'm releasing it under the GPL in case it might be of use to anyone else. You can download it here:


This is my first attempt at an Arduino library. Comments welcome.


Tim, N9PUZ

Tuesday, November 17, 2009

Temperature Sensing on the Cheap

Recently I was experimenting and needed a temperature sensor in a TO-92 type package. After a little searching I discovered the Microchip MCP9700A. This sensor is a bargain at about $0.36 each in single quantities from Mouser.

The interface is dead simple. Vcc, Ground, and an output that you can hook directly to an ADC input of a micro. The part I chose measures from -40C to +125C and outputs 10 millivolts per degree. If you need Fahrenheit temperatures it's easy enough to do the conversion once you know Celsius.

I tested the sensor out with one of the Arduino boards and easily had it measuring and displaying room temperature in about hour.