Neozap.com - Home made ECG number 3
For the princely sum of AUD$26 this (late seventies?) behmoth was mine.
A Fukuda Denshi FK11 electrocardiograph
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.
Time warp!
Here's a closer look:
You will see that I have been testing the thermal paper printer. The ECG only traces one lead at a time, however I have reused the same piece of paper in the interests of economy.
The objective with this ECG was simple: Make a data connection to a PC and use FreeECG to display a trace.
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.
When on the DC mode, a 3.5mm male-male audio lead is used to connect 'ECG OUT' to the sound card on one of my computers.
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.
Here's a copy of the first trace I recorded on the computer (click for a bigger version)
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.
Even better, the thermal paper mechanism still works, so it is quick and easy to flip the switch and print out onto paper (for that retro feeling).
Here's a picture of the setup with an ASUS eee PC (fits very nicely).
The biggest stumbling block at the moment is software - FreeECG is basic, very basic.
A project to improve ECG software and hardware (open source) is in its infancy. Email for more detail.
