Harold Hallikainen wrote: >>> My irradiance >>> metermeasures >>> =20 > in uW/cm^2. It's based on the Taos > =20 >> TSL230R, whic= h >> =20 > is > =20 >> factory calibrated. The construction isn't too difficult and uses the f= ree >> Amicus Compiler so there's not too much involved in making it happen. If >> =20 > nothing is available at a reasonable cost, this would be a way to get > what you're after. > > Thanks for the comments. I'm currently making a SIMPLE IR irradiance mete= r > adapter that plugs in to a standard digital voltmeter. It's based on the > TSL267-LF . However, the device is not calibrated. Under 4.4uW/cm^2, the > output voltage is somewhere between 1.2 and 2.8V with typical of 2V. So, > that's +/-40%. The TSL230R appears to be +/-20%. The difference with the > 267 may be the higher sensitivity (larger feedback resistor). So... next > question, how about a calibrated IR source? LEDs seem to have an even > wider variation. For example, the TSFF5410 is somewhere between 40 and > 200mW/sr at 100mA. > > I have access to a type A standard illuminant and, I guess, with enough > math, could determine the mW/cm^2 over the spectrum received by the > TSL267. > > Other ideas on generating a standard to calibrate such an instrument? > > Thanks! > > Harold > > > =20 I believe one on the variants of the TSL230 that have tighter specs. =20 The frequency of the output signal could be read with a DVM, but the TSL230 has an=20 "electronic shutter" to ccontrol sensitivity - more or less of the sensing element is used to=20 control sensitivity. Jon --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .