PillarSoft

This, being the first attempt at reading a meter, turned out to be a mind boggling experience. The manufacturer of the Accu-Chek meters was not very forthcoming about how to access the meters or how to read the stream of data that comes from it. I was told explicitly that the interface is proprietary and no amount of coaxing has led to any information.

As I know nothing about reading a serial port but have learned just enough to get the data from the glucometer. Without the manufacturers help this turned out to be ALOT of work. After much head scratching and "alot" of time, I was able to figure out most of their code. I am still missing a few pieces of the puzzle but hope to get it done eventually.

Here is the process I went through with the Accu-Chek Advantage:

1. First I ordered the Camit software from the manufacturer.
2. I ran the software and did a download.
3. With the help of Ray Gwinn's PmLm (Poor Man's Line Monitor) I was able to watch the data flow. (Thank you Ray!) 
4. Tried to find a pattern in the data. There were no delimiters but it wasn't too difficult to pick out the pattern of fixed length records.
5. Then I broke the data into chunks according to the pattern.
6. The raw data made no sense at first glance so I wrote a few mini apps to do every kind of conversion I could think of to it with no real luck.
7. I wrote another mini app to take the known readings and place them along side of the raw data along with some of the conversion variations I had done and began looking for some clues.
8. After noticing the first similarities between records with alike fields it began to unravel. (slowly)
9. After untold hours, I was able to get the Month, Day, Hour, Minute and Bg reading.

I have not been able to get the Year information yet. I believe they use a 2 digit year but because the two digits at this time are '00', they do not affect the data. I may set my meter date to 1999 or 2001 to try to help figure this out. For now, I have just plugged in the year data at "2000" until I get that part figured out.

I must say... I am amazed at how much information can be packed into so few bytes.

The Accu-Chek Advantage Puzzle:

BgMetrics also writes a refreshed data file with every download called "BgMetric.raw" that contains the bulk of the raw data downloaded from your meter and the conversion of it. If you like puzzles, take a peek at it and see if you can figure out where the year data is. I have a pretty good idea but am to tired of looking at it for a while to figure it out.

Your hint for the puzzle is that each record is exactly four bytes long and contains the Date, Time and BgLevel. The file lists the raw 4 byte record along side it's decoded data.