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this repo is for dry-cell battery testing of batteries in developing countries using simple microcontroller-based data acquisition. a 10-bit ADC on an atmel 328 is used with the arduino environment. ADC0 is connected directly to the battery output. ADC1 is connected to the high end of the shunt resistor to measure the battery current. Current source an opamp controlled constant current source is used to program output current. a voltage divider is used to set a bias voltage. opamp feedback adjusts the current source until the voltage across the shunt resistor equals the voltage on the divider. at 100 mA, the 1 ohm shunt resistor has a voltage of 0.1V. this means that the opamp must be able to tolerate a voltage close to the zero rail. i'm also experimenting with storing the data or results in a sqlite database LCD should update faster than sample output to file microcontroller: sippino was chosen for ease of breadboarding and access to AREF pin. shunt resistor: 1 ohm mosfet: 2N7000 opamp: LM358 voltage reference: 10K resistor and zener reg 2.5V nominal note: plugging in serial pin of open log affects current reading on the digital multimeter but not the LCD readout. (this could be because the change on the multimeter (3mA) is not within an LSB of the ADC.) however, this shows that you need to separate digital and analog ground since additional current is flowing through the battery circuit.