Hi Kone

You have nice setup I am looking forward what is capable of 

I will post new video today with interesting stuff I just have to put it together.

Kone I like to make my Arduino controlled circuit better. I am looking in way how to measure cap ( the one I am charging with BEMF ) voltage with arduino.

I like to do that SSR triggers dump to load when cap voltage is 100V and then SSR disconnects the cap from load when cap voltage falls to let say 50V.

The analog read input pin of Arduino is limited to 5V. It would be nice if measuring cap voltage with Arduino would be optical isolated.

Regards JoeFR

Quote from: joefr on August 16, 2011, 02:56:00 AM
Hi Kone

You have nice setup I am looking forward what is capable of 

I will post new video today with interesting stuff I just have to put it together.

Kone I like to make my Arduino controlled circuit better. I am looking in way how to measure cap ( the one I am charging with BEMF ) voltage with arduino.

I like to do that SSR triggers dump to load when cap voltage is 100V and then SSR disconnects the cap from load when cap voltage falls to let say 50V.

The analog read input pin of Arduino is limited to 5V. It would be nice if measuring cap voltage with Arduino would be optical isolated.

Regards JoeFR

Hey Joe, that is a good idea. You could use a voltage divider. All you need is two resistors of the right value. Here is a thread about how it's done with Arduino: http://forums.adafruit.com/viewtopic.php?f=25&t=18804

Hi chalamadad

Thanks for the link. The voltage divider is the easiest solution, but I like to have optical isolated input so that I dont burn arduino if I make some programming error.

JoeFR

Quote from: joefr on August 16, 2011, 04:43:04 AM
Hi chalamadad

Thanks for the link. The voltage divider is the easiest solution, but I like to have optical isolated input so that I dont burn arduino if I make some programming error.

JoeFR

I'd use an additional 5V zener diode for protection.

Edit: If opto isolation is a must I can imagine that you could get it done with some kind of voltage to frequency converter somehow.

Hi Joe

More on the coil-shorting of the motor coils - in the scope shot of most anyones RomeroUK machine with the magnets back there and the rotor magnets being attracted in the pulse to the motor coils, the motor coil looking with scope at it will show that the motor pulse will be right at TDC of the sinewave created by the rotor magnets give or take a few degrees, and then the sinewave plunges down and then you have a negative-peak phase - and this neg phase has "nothing" happening to it....this would be ideal place to do the coil shorting at peaks - at only the neg phase peak -  and let the  pos phase peak where the motor pulse occurs have a backemf/recoil diode-collections circuit on it. Anyways thats what I am thinking to do right now in how I am going to position the new hall effects to control and time the coil shorting - maybe will have two caps one for the backemf/recoil and one to collect from the coil shorting maybe not...