I have made a suit covered in EL wire that responds to the wearers heartbeat for a dance performance. Independantly, the circuit switching the EL wire and the circuit with the heart rate monitor work fine. However when the heart rate monitor is too close to the EL wire it gets interference and cant produce a regular signal. I know El is known for creating electrical noise, so i was wondering if there is any known way around this problem.
I am using an optocoupler and triac to switch the EL wire. The inverter powering it output 110v ac at 1800Hz.
The Heart rate monitor is is a Polar T31 chest belt and Polar receiver RMCM01 this transmits low frequency EMF.
There are a couple of approaches i am considering to try and get around the interference problem:
try using a different heart monitor. Garmin produce a chest belt monitor that works with this receiver http://www.sparkfun.com/commerce/product_info.php?products_id=8565 one that works at 2.4GHz the problem with this plan is that it costs a bit so i didn’t want to try it on the off chance it will work.
making my own Heart monitor using two stick on electrodes http://pulsemedical.co.uk/product_info.php?cPath=50&products_id=137&osCsid=b81f213296a3437ecabf3beff441e783
and amplifying the signal. I was going to try using this preamp http://www.maplin.co.uk/module.aspx?moduleno=37746
I was planning on running it into an analogue pin on the arduino and setting it to read as ‘high’ when the voltage crosses a certain threshold (though im not sure how to do this yet). As far as getting around the interference problem with this design i am going to use screened cable and put the amplifier in a metal box.
Any Ideas Folks? Any input is much appreciated.