slave device

Both Electromagnets are fixed within the CRT and both signals pass from the arduino through them and alternating frequencies. however due to a change in sensors at the last minute , the code was not performing correctly and needs some readjustment. 

- circuit soldering

Clip taken from one of many experiments in where to place the electromagnet.  This time it was placed under the cathode ray tube, nice subtle effect. 

First test using the first capacitive sensor with the electromagnet + CRT. 

Testing a range of wave signals from the arduino, and sampled wave tones from the internet for comparison through a homemade oscilloscope.... (sadly this CRT came to an unfortunate end early on in the project and so will forever only be an oscilloscope). 

Also had to change the design of the original circuit so as to free up some pins, (as for the capcitive sensors I would need pins 2, 4 and 5).  This was done using a 1-bit DAC instead of the R2R ladder and some alterations to the code, resulting in only pin9 needed  for PWM output. 

Testing with oscilloscope...no longer getting a perfect  sine wave, puzzled.  Tried replacing odd resistor in R2R ladder and checking over circuit on breadboard along with the code but all seemed correct. 

Testing the effectiveness of the Electromagnet on the CRT Monitor.  Square wave sent from arduino , passed through an R2R ladder, Low Pass Filter and Op Amps to change the signal to a sine wave.  This is then passed through the electromagnet which is placed near the Cathode Ray Tube. (Image present on the monitor is a Jpeg from a media player).

// later discovered that I should not have used LED’s as something to pick up with electromagnet as they are polorised and so will short out hardware.

Resitance = 9.1 Ohms

Sine Wave with potential controlled applitude, to Mono Jack for audio output, which will be passed through the electromagnet.

2. Op Amp installation Schematic.

If I amplify an audio signal, such as a sine wave (from the arduino), and replace the speaker with the magnet, I will have a magnet that is rapidly switching polarity. This is more effective than a stationary magnet as I'll be able to make an image wobble over time rather than just a still distortion. 

result:  sine wave!

R2R Ladder test.