On 2013-03-27 18:31, Martin Peach wrote:
On 2013-03-27 17:17, Julian Brooks wrote:
Hey Martin,
Good to hear you've got one of these too.
Yes I meant [comport] with the xbee rather than [hid] sorry, getting my physical input objects confused.
Will check out the links you provided as part of my getting up to speed.
So, managed to get the sensors out of the cardboard box. They are tiny. Like little sci-fi robot eyes.
1st problem is that we don't have any of these: 'JST (Japan Solderless Terminals) - PHR-4 - Housing, 4way, 2mm
http://uk.farnell.com/jst-japan-solderless-terminals/phr-4/housing-4way-2mm/...
Which is a vital £0.04.6 of equipment as the sensors pins are way too tiny to be poking bits of wire into. These attach to the bottom of the board and then 2mm cabling attaches to them and out to the Pi.
Got some off ebay as farnell has a £20 minimum spend that's a bit over getting 10 of those suckers. So going to have to wait a few more days as I can't find any in my vicinity at all. Bollocks.
Yes I got mine at Digikey. You need the terminals as well as the housings. I crimped the terminals to some 28 gauge wire and also put a bit of solder but not too much to plug them up.
Today I managed to get data using an Arduino and the Wire library, with 4.7k pullup resistors on the clock and data lines. The packets are only 32 bytes, not 35 as the app note says. Not sure what's up with that.
I changed the default buffer size in Arduino's wire library from 32 and now I get 35 bytes as advertised. The crc calculation is not giving me the right answer but that doesn't seem to matter. I get 16 pixels of temperature, it's detecting warm as well as cold objects, quite a nifty sensor!
Martin