Wednesday, January 10, 2007


In order for Pompie to work correct Pompie need to sense the temperature. The circuit on the left uses a 15k resistor to limit current, a 15k NTC for the temp. The reason for 15k is the graph of measurements shows an almost strait line, another reason is that the scale is perfect for the dot on the globe I live. Say you need a NTC to measure the temperature and your location it will never be lower than let's say 10C its advisable you use different values, start with 5k and make a similar graph. The third reason is that the program can detect a faulty wire. To make a graph:
  1. Melting water = 0C
  2. My freezer freezes at -18C
  3. My central heating is set to 20C
  4. My (and your) hands are about 32C
The rest you can do with openoffice calc.

Code to test the NTC is the same as the tutorial for the potmeter.

Next will be switching 220VAC

1 comment:

Bill said...

do you linearize the NTC curve?