Thanks "RTUSA" all sorted now. It turned out that it was all grounded rather too well! I had connected the reed switch to earth rather than the 5 volt feed! Also the magnets that I had glued onto the front hubs had been cooked by the heat from the brakes and lost their magnetism. So I will...

I should read things before posting them! Its a reed switch obviously.

I am attempting to use a read switch and magnet to monitor wheel speeds. Am I correct in thinking that the way to do this would be to use the read switch to send a battery pulse to the frequency input? I have just tried this configuration but nothing is being recorded on the DL1 frequency channels. ...

Are all 8 analogue inputs now available for use on the new version of the DL1?

Looking at my first log file, none of the inputs appear to be tied to the battery.

Andy.