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Electronics => Electronics => Topic started by: z.s.tar.gz on July 28, 2011, 08:49:33 PM

Title: Coilgun-turret-robot-thingy for a project but how to make high enough voltages?
Post by: z.s.tar.gz on July 28, 2011, 08:49:33 PM

I'm trying to combine a coilgun and a robot but my major stumbling block so far is a way to create high enough voltages but still keep the robot portable.
My only idea is so far is to have several banks of progressively larger caps be charged in parallel and discharged in series but that seems a bit (extremely?) too much.

Any good ideas?

Title: Re: Coilgun-turret-robot-thingy for a project but how to make high enough voltages?
Post by: BigKLaxer on July 29, 2011, 07:07:29 AM

I actually encountered this problem a few months back when my roommate and I tried to build a coilgun.  It didn't go anywhere, but we learned a lot.  We got a bunch of used disposable cameras for free from the local drug store and took them all apart.  Inside each one they have a circuit that brings up the 1.5V of a AA to a couple hundred volts to charge a cap.  You could always get one of these circuits and wire a bunch of caps in series to the original one.

Title: Re: Coilgun-turret-robot-thingy for a project but how to make high enough voltages?
Post by: waltr on July 29, 2011, 08:04:38 AM

Quote

a circuit that bring up the 1.5V of a AA to a couple hundred volts to charge a cap

yep, some type of DC-DC switching PS.
Do some googling and you'll find many examples.

Title: Re: Coilgun-turret-robot-thingy for a project but how to make high enough voltages?
Post by: Soeren on July 29, 2011, 10:38:01 PM

Hi,

Quote from: z.s.tar.gz on July 28, 2011, 08:49:33 PM

[...] my major stumbling block so far is a way to create high enough voltages but still keep the robot portable.
My only idea is so far is to have several banks of progressively larger caps be charged in parallel and discharged in series but that seems a bit (extremely?) too much.

If you'd use a Cockcroft-Walton multiplier (which would be extremely inefficient for a coil gun), you'd use progressively smaller caps, as the higher the stage, the less charge is transferred at each blurb.

A single power transistor and a transformer (plus a couple of small caps and a resistor or two) is all it takes to generate a several hundred Volt output with plenty of oomph - and it's the oomph that makes the caps charge quickly.

What's your power source and how high a voltage do you need?

Title: Re: Coilgun-turret-robot-thingy for a project but how to make high enough voltages?
Post by: Conscripted on July 30, 2011, 08:05:51 AM

I'm not working on this project but I'm very interested. I have built a couple of coil guns from disposable cameras. How would you power a coil gun from a 7.2vdc battery on a robot? How would you provide the AC current for the transformer? Would it require any special steps to prevent the coil from interfering with regulated 5vdc for the robots logic?

As I said I'm very interested
Conscripted

Title: Re: Coilgun-turret-robot-thingy for a project but how to make high enough voltages?
Post by: z.s.tar.gz on July 30, 2011, 03:33:46 PM

Let's call it 3V from two AA cells.
Reading up on how cameras work I see the big trick: instead of making AC you only need to make short pulses of DC.
Now that I know how to use the transformer correctly creating high voltage won't be a problem at all.