2010-02-24

MAC OS X

I am now working on a new release of the Analyzer. My goal is to include support for MAC OS X in this release, and I am currently getting help in solving the problems that surface in that OS. The old Java promise “Write once – run everywhere” is not entirely true… There are still some problems with both SWT and the sound samplings. Hopefully we will have these problems solved soon so beta testing can begin.

I have also discovered that the hardware modification of the UPM-thermometer does not work well with some USB-sound cards. I have received good feedback and alternative connections from users (thanks Walter) and I will update the descriptions on the site.

2010-02-01

UPM Checksum

A while ago I discovered four extra bits in the UPM temperature RF protocol. Two of the bits are sequence counters which simply adds one for each message in the three message bursts sent by the sensors. The other two bits seemed to be some kind of checksum. I have had some reports of people getting bad readings sometimes, so I finally took the time to figure the checksum out. After a bit of experimenting and analyzing, I finally managed to decode it: Bit 0 is all even bits in the message XOR:ed together and bit 1 is all the odd bits. So now bad messages will not be reported from the receiver any more!