Neozap.com - Home made ECG number 3
You might notice that it came with suction cap electrodes (top left) made of rubber and very corroded copper bell housings. Additionally, spare paper rolls and the original instruction manual was also provided.
Here's a closer look:
Here's a picture of the port on the side of the ECG.
Conveniently it has a 'DC' setting which prevents the needle from flickering and the paper from rolling. It is interesting to note that the servo is still on, however, and hums quietly.
The microphone volume was set to roughly 1/5 to 1/4 of maximum, and VERY IMPORTANTLY the software 'Microphone boost' provided in WinXP was turned off. A terrible trace results if this is left on.
As you can see the noise levels are unusually low, possibly due to an excellent 50Hz filter, shielded cables and/or lower background noise.
This conversion was very easy, as no converting was required. Just a cable and the software. No doubt many other ECGs exist similar to this one - and just as easy to convert.
Here's a picture of the setup with an ASUS eee PC (fits very nicely).