[Nottingham] Arduinofiddles

Chris Burton Chris at 7of9b.org
Thu Mar 6 11:12:42 GMT 2008

 Just thought I'd update the group with my Arduino fiddling...

My project was to graph the Amps in/out and battery voltage in my solar 
setup. I ended up getting a Decimal and Bluetooth Arduino as I figured the 
Diecimila would be easier to fiddle around with before adding BT to the 
list. The Bluetooth was a bit of a pain as I had to recompile RXTX to get 
the GUI to show /dev/rfcomm properly and luckily I already had a Bluetooth 
dongle that worked in Linux. Uploading to the Bluetooth was also a pita it 
seems there was lots of luck involved with timing to get a successful upload 
but I got there in the end.

On the Arduino I just read the ADC values and send them back on the serial 
line as a single line of text every few seconds which I poll from Linux via 
the BT and stick into a data file after scaling it to Volts. I could just 
graph it from here but since I like Cacti (and graph from multiple machines) 
I use SNMP to read the voltage value from the data file. The SNMP script 
doesn't talk directly to the Arduino as the script sometimes runs for a 
while trying to get the BT connected to the Arduino again as it seems 
unreliable at times - I really need to remember not to put bottles of water 
in front of the dongle ;).

At the end of all that mess I end up with the Volts graph (its a bit out but 
is good enough for me):

I've just ordered the bits to add current measurements and hope to get that 
setup over the weekend :).

What's everyone else using theirs for?


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