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IO Interrupt Speed from managed and RPL code


Hi All;

I’ve just ordered a FEZ panda II for a project where by I will be pulsing coils with High voltage and was going to use a Hall effect sensor to mange the resonece between the coils (when one coil is pulsed driven by sine wave from a High Voltagesource, it induces and cusrrent in the secont coil which the Hall effect sensor picks up and stops the HV source untill the magnetic field colapses in the second coil. then fires the next pulse by starting then sine wave again and the process repeats idefintilay, i was also going to generate a sine wave from the FEZ Music Sheild if this is possible ??? )

My question is how fast wold it be possible to drive this proceess i’m asuming i could generate this from an interupt but I’m not sure how fast i could process this basic task in managed or unmanged code?

Can one give me a view on this or even a better solution to managing the switching of coils?

Thanks in advance




Netmf isn’t particularly great at this kind of thing. It sounds like you need tight timing and very short delays between detecting the coil voltage an triggering the next. I wouldn’t count on anything higher than about 1khz in a reliable way. Netmf is really meant to make the higher order logic easier to apply and kind of sucks with the real time stuff.

It’s hard to picture what you are trying to do. A rail gun maybe? :slight_smile: The basic building blocks of what you are describing is probably best done with a comparator, delay line and fast switch (mosfet). A 555 actually comes to mind.

If you think about it a brushless motor speed controller does something similar. Maybe that could be way to physically interface? The Panda is very good at talking PWM to these.


Thanks for your reply, 1Khz may be good enough, I currently control the resenence through ferrite core rod and a few 2n3055 power transitors but to switch this at hight voltage 2000 - 4000 v i would need to buy a very expensive IGBT transitors (not going to happen this is a home project) therefore i was hooping top control the input voltage to some car ignition coils currently driven by pc based signal generator by the Panda instead using the hall effect switch sensors to contol the firing pulses (they are iregular becuse of the spark gap).

Your way sounds more sensible but I’m an technical architect by trade with a basic electronics and desktop programming background (some java embeded programming on the TINI chipset from maxim) so i’m quite limited in what I can do. I will certainly reserch your thoughts though :slight_smile:

It’s not a rail gun but the process for generating a large magnetic pulse is the same so you were on the right track :wink: