Schematic and board

Before I have built a sensor on a PCB, the Smartmeter IR signal was read with an Arduino and a phototransistor. The schematic is very simple needs only one transistor, a resistor and the phototransistor to work. The Arduino operates purely as a USB to UART bridge and is held in constant reset (no firmware required). The optional LED indicates when a datagram is received. For the phototransistor I used a SFH309 from Osram, which is sensitive in the IR range and blocks the ambient and was soldered on a small piece of strip board. A long flat ribbon cable connects the IR sensor to the breadboard.