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Step 5Transmitter Circuit
The Transmitter circuit is simple. I chose a 100 kOhm resistor for R2 since it looked like it would fit the range from the graph, and I had a spare one from desoldering various things with the Minions. I connect this in series with the Thermistor via a connector. Then I added a battery pack. I Ran 3 V to VREF and the Top of the Voltage divider and to the Xbee +3V input. I put the GND (Battery Negative) to the GND input, and to the bottom of the divider. I then connected AD0 (Volts in) to the middle of the Voltage Divider Circuit.
AD0 will read a relative voltage from VREF to V(1). So as the battery declines, the relative voltage should decline the same. Eventually I will power the unit with a local power source.
The finished unit worked fine, we connect everything with alligator clips, which made it fragile. After I got the female 3/32" connection, I place the transmitter in a random plastic tub we had (an ex-hummus container). This should protect it from weather. Since I bought "panel mount" connectors, it was as simple as drilling a hole in the plastic to add the connector to the outside with a fairly water tight connection.
Once we had that it was time to test.
AD0 will read a relative voltage from VREF to V(1). So as the battery declines, the relative voltage should decline the same. Eventually I will power the unit with a local power source.
The finished unit worked fine, we connect everything with alligator clips, which made it fragile. After I got the female 3/32" connection, I place the transmitter in a random plastic tub we had (an ex-hummus container). This should protect it from weather. Since I bought "panel mount" connectors, it was as simple as drilling a hole in the plastic to add the connector to the outside with a fairly water tight connection.
Once we had that it was time to test.
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