A friend recently send me a Current Cost Optismart sensor to test compatibility with the emonTx / emonPi, here's what's inside the sensor:
Brown is 0V. So LED is energised from Green via 220R.
Phototransistor has 150K pull-up to Red Vcc supply.
Black is TTL output
Re: Current Cost Optismart Optical Sensor Tear Down
After a quick initial testing I can conclude that the CC optismart sensor will work with the emonTx V3 / emonPi. Using the following connections:
Red: 3.3V (terminal block 2, RJ45 pin 2)
Brown: GND (terminal block Pin 3, RJ45 pin 1)
Black: IRQ (terminal block Pin 4, RJ45 pin 6)
The LED on the rear of the sensor won't work unless the green wire is connected to a free digital I/O on the emonTx and code added to toggle this pin when a pulse is detected, on the emonTx V3 Dig19 / ADC5 could be used.