Hats off to you for tackling the arduino Bob! I bought one for the very same reason....The cap dump!!! I have fried more components trying to get a reliable cap dump circuit working over the last 6 months and then I heard about these wonderful micro controllers. It took me a while to get the hang of programming it but there's no looking back now. Cap dump, frequency meter, back popper, oscillator driver, battery swapper...It's all possible now.
it's funny that you mentioned the radiant energy released when a switch closes. I'm not 100% sure but when my cap discharges, I'm seeing what looks like a radiant spike extending downwards on the scope for about 4 volts. In other words my cap discharges at 30 volts down to 23 volts for under 1 ms then jumps back up to 27 volts after that 1 ms and ramps back up to 30 volts from there. I didn't see this with my other dumping setups. Maybe I wasn't driving the mosfet gate high enough?
I've only had the setup working for a few weeks or so and I've dumped caps from 750uf at an insane rate to .4F with this thing and man what a difference. When I dumped the .4F cap the noise was somthing to behold. usually a cap dump sounds like a clock tick but when the energy hit the batteries, it sounded more like a loud clock TOCK. It scared the hell out of me and I immediatly shut it down.I thought the batteries were going to explode.I don't recomend working with these monster caps unless you know exactly what you are doing. I don't ...so for now I'll just stay alive, put them aside and work with the little guys.
The thing I find most usefull about using the arduino cap dump and it's frequency meter is you can play the "what if" game. I'm using it to evaluate the different components of the oscillator by keeping the input current constant and noting the frequency of the cap dump. Then you can try different diodes, coils, cores, caps, transistors...etc and immediatly see if your change is good or bad by an increase or decrease in cap dump frequency. It's amazing what affects the sg oscillator. Just touching certain wires or hooking meters or scope probes will change the dump frequency.
A friendly suggestion for you Bob is rather than using a time based cap dump maybe use a voltage based dump. I'm using a zener diode to set the max cap voltage (an input to the arduino through an opto) and code the output to dump when the arduino sees the input. so far it seems to be very stable and repeatable but best of all....no smoke. The reason I say this is i don't know about you but I have a drawerfull of caps that have been blazed by way more voltage than they are rated for simply because of my time based cap dumps either failing or I started the system with the wrong timing. The voltage based dump always dumps at the same voltage no matter what size cap you use and you can choose when to deactivate the output in the code to dump at a fraction of a volt or all the way down to battery voltage.
I have to ask you Bob where you got that wonderful software that graphs the battery charging curve I saw in your video?
Very impressive setup Bob.
Emp
it's funny that you mentioned the radiant energy released when a switch closes. I'm not 100% sure but when my cap discharges, I'm seeing what looks like a radiant spike extending downwards on the scope for about 4 volts. In other words my cap discharges at 30 volts down to 23 volts for under 1 ms then jumps back up to 27 volts after that 1 ms and ramps back up to 30 volts from there. I didn't see this with my other dumping setups. Maybe I wasn't driving the mosfet gate high enough?
I've only had the setup working for a few weeks or so and I've dumped caps from 750uf at an insane rate to .4F with this thing and man what a difference. When I dumped the .4F cap the noise was somthing to behold. usually a cap dump sounds like a clock tick but when the energy hit the batteries, it sounded more like a loud clock TOCK. It scared the hell out of me and I immediatly shut it down.I thought the batteries were going to explode.I don't recomend working with these monster caps unless you know exactly what you are doing. I don't ...so for now I'll just stay alive, put them aside and work with the little guys.
The thing I find most usefull about using the arduino cap dump and it's frequency meter is you can play the "what if" game. I'm using it to evaluate the different components of the oscillator by keeping the input current constant and noting the frequency of the cap dump. Then you can try different diodes, coils, cores, caps, transistors...etc and immediatly see if your change is good or bad by an increase or decrease in cap dump frequency. It's amazing what affects the sg oscillator. Just touching certain wires or hooking meters or scope probes will change the dump frequency.
A friendly suggestion for you Bob is rather than using a time based cap dump maybe use a voltage based dump. I'm using a zener diode to set the max cap voltage (an input to the arduino through an opto) and code the output to dump when the arduino sees the input. so far it seems to be very stable and repeatable but best of all....no smoke. The reason I say this is i don't know about you but I have a drawerfull of caps that have been blazed by way more voltage than they are rated for simply because of my time based cap dumps either failing or I started the system with the wrong timing. The voltage based dump always dumps at the same voltage no matter what size cap you use and you can choose when to deactivate the output in the code to dump at a fraction of a volt or all the way down to battery voltage.
I have to ask you Bob where you got that wonderful software that graphs the battery charging curve I saw in your video?
Very impressive setup Bob.
Emp
Comment