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dbrooke_nodes:db04

This AVR Sensor Board V3 node has all components and headers installed and has a DHT22 as the sensor. The antenna is a 1/4 wave wire.

It is running from 3 AA NiMH cells installed in a battery holder salvaged from a time expired CO detector. The battery voltage reading appears to not suffer from thermal error despite having 4M7 and 1M resistors in the ADC divider.

2015-01-20 15:45 - Having spent some time sitting on the workbench in the utility room it was placed inside a plastic drink bottle with the bottom cut off and moved out to a sheltered corner of the garden under a tree.

2015-03-24 - Since the move to an outdoor location it has become apparent that the battery voltage does suffer from error under conditions of low temperature combined with high humidity.

2015-07-23 18:30 - Resistors in the battery voltage ADC divider changed to 470k and 100k and the batteries recharged.

dbrooke_nodes/db04.txt · Last modified: 2015/07/23 17:35 by dbrooke