I’ve had a week off during which I’ve finally done some things I kept putting off. For as much as (nearly) two years!
I put together an Adafruit Protoshield to use with my Arduino. I bought both in January 2011, played a little with the Arduino and then put it aside until now.
Armed with the newly built shield I went ahead and messed around with multiple LEDs and a photoresistor. Then I put header pins on a 20 x 4 character LCD display I’d gotten earlier this year as a gift, and got that working.
Next I tried out a couple of devices I’d sent off for soon after learning about the JP Aerospace PongSat program: a SparkFun uLog data logger and a Pololu serial-to-USB board. The data logger can sample three analog inputs and store the data to flash memory for later readout; it has a serial interface so the serial-to-USB converter is needed for that. Sampling rate is 50 Hz as supplied though you could change that by reprogramming the ATtiny24 the uLog is built around. But at 50 Hz it can store 2 hours of data, enough to cover a PongSat flight. The uLog is 0.9 by 0.7 inches in size; with a suitably small battery it’ll fit inside a ping pong ball along with… what? I’m thinking temperature sensor. I’ve ordered a thermistor and a semiconductor temperature sensor from SparkFun to try out the idea, though both are rated only down to -40F, and that’s not low enough.
Anyway, I’ve connected up a photoresistor to the uLog, recorded some data, and read it back, and all that worked with no problems:
So progress is being made.
GE C100Y103J might be good. A 10K thermistor, 5% tolerance, rated down to –80°C. $2.46 each from Mouser.
Also, here http://www.rustynailworkshop.com/archives/10 is a report on another temperature (and humidity) sensing PongSat.