I am planning to do a project with a Arduino, where I can log the ussage of electricity and heat in my house. The electric meter has a blinking LED that I can read, and the heating meter has an IR input/output port, which I can communicate with. I need to order some components to be able to interface with the meters, and for that I need some advise what to buy.
Regarding the electric meter:
Can I use a LDR sensor like GL5528 http://www.sparkfun.com/datasheets/Sensors/Imaging/SEN-09088-datasheet.pdf to register the blinking, or do I need some special type of sensor?
Unfortunately my electric meter is placed outside the house, so the cable between the sensor and the Arduino must be ca. 10 meter long. I was thinking of placing a circuit at the sensor end with the LDR and a resistance as a voltage divider connected to the input of a Smith trigger, and then connect the output of the Smith trigger through the long cable to the input of the Arduino. Would this be a good idea?
Regarding the heating meter:
According to the documentation of the heating meter, the IR port is a serial port (8 databit, no parity, 2 stopbit, 2400 baud). I was thinking of connecting an IR receiver and transmitter directly the the serial port of the Arduino (port 0 and 1 on the Uno).
Would it be possible to connect the output of a TSOP32238 http://www.farnell.com/datasheets/30489.pdf receiver or similar directly to the RX port of the Arduino?
About the transmitter, I was thinking of connecting a diode like this http://www.sparkfun.com/datasheets/Components/LED/YSL-R531FR2C-F1.pdf in serial with a resistor. I would then connect one end to the TX output of the Arduino and the other end to one of the PWM outputs, and then make the PWM output pulse with 38 kHz. Would that work?
Please give me some feedback about my thoughts. My hardware skills are not so good, so if you have any suggestions about the hardware, I would prefer the circuits to be as simple as possible :)