Electronics
The detailed circuit diagram, and corresponding derivations, are available here: Circuit Diagram and Voltage to Temperature Derivations
All thermistors are: 235-165-ND: FP 07 FAST TIP PROBE, 150 Kohm, at 25C
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- Replace thermistors in test lines
- All are 5% 150 kOhm resistors
Wiring:For
Note: for the two reference lines (thermistor + resistor and resistor + resistor), a resistor might replace a thermistor in the description below. The wiring scheme is the same for all 5 lines, whether thermistor/thermistor, resistor/thermistor, or resistor/resistor.
- All lines are twisted pair, shielded wires
- For main line (that which includes both thermistors):
- low wire (black wire) is connected to low end of power supply (which can be ground)
- high wire (red wire) is connected to high end of power supply
- Top thermistor in voltage divider configuration is soldered directly into high (red) wire
- Bottom thermistor in voltage divider connects high and low (red and black) wires
- Shield is connected to ground (unattached at the end with the bottom thermistor)
- For the sample line (running off of midpoint of thermistor voltage dividers)
- High (red) wire is soldered to the middle side of the top thermistor (side between thermistor pair)
- Low (black) wire is shorted to shield
- Low (black) wire and shield are connected to ground on measurement end of array, unconnected on end connecting to thermistor
ADU Board
Jim's Arduino-based hardware
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