I have a wireless energy meter and thermostat at home. I could try to hack them, taking them apart and listening to certain key voltages. However, the circuits are likely small and breakable. And I would like to use the units again and not pay for replacements.
So I was wondering whether I could cheat and input data values using OCR from a webcam or camera. The Raspberry Pi would be well placed to do this. My thoughts so far for the process are set out below. I can probably tackle each independently.
- Place meters;
- Acquire image;
- OCR on image;
- Output of OCR to DB or file.
1. Place meters
- Needs to be a set distance from acquisition device;
- Mark out so can replicate even if need to take meters in and out;
- Illumination for night time:
- Low power (LED?)
- Filter image when LED is lit?
2. Acquire image
- Frame grab from webcam;
- Need to get webcam working;
- Need to learn command to acquire image;
- Segment image for different data:
- Set x,y area in image if meters are placed consistently;
- Is there a command line tool for this?
- Test with crop in iPhone/iPad;
- Output image files for different areas – use these as input for OCR.
3. OCR on image
- No obvious OCR tool on Raspberry Pi – keep looking;
- Web services? Does Google/Tesseract have a web service? Use URL?
- Did common sense check on output:
- Values will be integer (input parameter for OCR)
- Values will have decimal point;
- Create own OCR tool?
4. Output of OCR to DB or file
- MySQL DB?
- Key field = time stamp (inc. seconds);
- Other fields for each item of OCR data;
- Or flat file, e.g. CSV, with {timestamp, data} tuple.
Robotic Ape 