I've searched through the forum and wasn't able to find how to map the values of a sensor being interfaced with a non-phidget ADC converter.
The device that I'm using is a Bluesentry node, that allows up to 8 channels, i.e. sensors, to be connected and for their respective values to be transmitted over a bluetooth connection. Bluesentry provides, for each channel, a 16-bit precison in the 0-5 Volt range. Just for those of you who are curious, you can check Bluesentry at http://www.rovingnetworks.com/bluesentry.htm.
I was able to solder a Precision Temperature Sensor (Product ID = 1124) to the Bluesentry unit, and I'm also able to obtain readings from the sensor. The problem is that I cannot map the 16-bit value that I'm able to read into a meaningful temperature value.
I've gone through the Precision Temperature Sensor 1124 product manual, available here http://www.phidgets.com/documentation/Phidgets/1124.pdf, which mentions the following formula:
Temperature (Cº) = ((Vin * 200) * 0.2222) - 61.111
Yet, when I employ the above formula, with Vin as the sensor reading obtained, I obtain values in the 35-40ºC range. Yet the room temperature where I tested the temperature sensor was set by the Air Conditioner to 24ºC.
I've also noticed that the initialization code provided for the temperature sensor in the source code for Phidget 21 MSI is quite complex and seems to configure the temperature reading whilst contemplating the sensor model and also with data provided by some lookup tables.
Shouldn't the formula provided in the product manual be enough?
I would appreciate, a lot =), any suggestion, specially if someone has any idea regarding some possible factor that I'm not contemplating, or if any of you has had hand-on experience with this kind of problems.
Thanks in advance.