voltage measurement using ADC
bnrg
Posts: 14
in BASIC Stamp
Hi,
I would like to monitor an AA CELL (1.5 vdc) battery voltage and am using the example shown in the Parallax 'Basic Analog to Digital' course, chapter 3 figure 3-3, both program and schematic-it uses an ADC0831. When running the course topic all works fine and the voltage reads correctly. To incorporate my battery I attach the connection for pin 2 (Vin) of the ADC to the neg side of the battery. The result in debug is very noisy and frequently changing at an almost unreadable rate, but values that look like anything form .5 to 4.0 are showing up. The circuit is otherwise as shown in the schematic which has a steady ref (Vdd) on Vref and I would have thought that the battery would be pretty quiet noise wise. Is noise an issue or is there something else going on? For this test there was no load on the battery.
Thanks,
Bob
I would like to monitor an AA CELL (1.5 vdc) battery voltage and am using the example shown in the Parallax 'Basic Analog to Digital' course, chapter 3 figure 3-3, both program and schematic-it uses an ADC0831. When running the course topic all works fine and the voltage reads correctly. To incorporate my battery I attach the connection for pin 2 (Vin) of the ADC to the neg side of the battery. The result in debug is very noisy and frequently changing at an almost unreadable rate, but values that look like anything form .5 to 4.0 are showing up. The circuit is otherwise as shown in the schematic which has a steady ref (Vdd) on Vref and I would have thought that the battery would be pretty quiet noise wise. Is noise an issue or is there something else going on? For this test there was no load on the battery.
Thanks,
Bob
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