Date:   11/5/2016 2:10:20 PM ( 8 y ago)
Hits:   3,093
URL:   https://www.curezone.org/forums/fm.asp?i=2341762

Thanks for the useful post you have made. I am sure that some people will find it helpful.

I think that I would rather use 4 9v batteries if I was doing it this way.

Batteries can be hooked together terminal to terminal to reduce the cost further if needed. Then people could get away with using just two 9v battery clips. Not ideal but it does work if every penny counts. However using a DC Boost converter with a cheap 12v regulated power supply would probably work out cheaper in the long run and be less of a hassle with batteries.

Hooking the 4x9v batteries terminal + on one to - on another and so on. Then you only need 2 battery clips on each of the free battery terminals. Not quite so secure but it requires less parts and the voltage is higher.

What are your thoughts on the EMI from the magnetic stirrer? Have you ever tested it? Using something like a portable AM radio and putting the earphone leads next to the stirrer and adjusting the frequency and listening for any noises.

I have a PWM fan controller which has an aluminium case and putting an AM radio near it does produce some noise on the radio. I have not yet grounded it or put it into an outer case but I am aware of EMI and want to keep it to an absolute minimum. Have you tried doing a similar thing with your magnetic stirrer? CS is sensitive to EMI and electric fields.

I wonder how well shielded some of those inexpensive magnetic stirrers are. Any ideas or thoughts on this?

This is proving to be the most challenging part of the whole project. I wonder whether purchasing a magnetic stirrer would be cheaper or whether I would end up with some EMI broadcast station which adversely affects the CS. Few people seem to take this into account from what I have seen. "Build your own magnetic stirrer from a fan and a plastic carton." type of guide.

I prefer the idea of a magnetic stirrer to a bubble mixer as I am not convinced about introducing air into the process or dust for that matter.

What is the reason for the wide separation of the electrodes? Is it to avoid the possibility of the doubled/bent electrodes from coming into contact with one another? From what I have seen, the recommended separation is only meant to be around 20 to 25mm or approx 1". However when using a bend in the electrodes it makes it harder to avoid them touching one another and shorting.

I thought about using a terminal block to retain the electrodes and prevent them from swinging into one another. That would allow the electrodes to be locked with a screw. I have some already and one size I have seems to fit quite nicely. I am using a 2 litre wide mouthed (70mm) erlenmeyer flask so separation distance is a bit limited

I believe that having a wider separation would tend to slow the process down by lowering the flow of charge between the electrodes.

Your thoughts on the EMI in particular would be helpful as I still have some parts to order such as a case for the magnetic stirrer.

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