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Topic: I need help to design a circuit to control a latching solenoid (Read 2115 times) previous topic - next topic

szangvil

I have an on/off foot paddle I want to connect to latching solenoid. When I press the peddle, I need to send a 100ms pulse to the solenoid. As long as I keep the foot down pressing on the peddle, nothing should change. When I take my foot of, I need to send another 100ms pulse.
The solenoid will open when it get a positive 6VDC pulse and will close when getting a negative (-)6VDC pulse.

I don't really know how to start, but I know I don't want to use a microcontroller and I think a 555 timer can do the trick.

fungus

#1
Jan 31, 2013, 11:36 am Last Edit: Jan 31, 2013, 11:58 am by fungus Reason: 1

I don't want to use a microcontroller


So why are you posting in Arduino forums? :)

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

Grumpy_Mike

Use a h-bridge to drive your solenoide and a 555 as a monostable to generate the pulse. The pulse should do two things, enable the h-bridge and trigger a flip flop. The output of the flip flop should drive the h-bridge direction.

szangvil

But how do I keep it from generating pulses when the pedal is kept pressed?


fungus


But how do I keep it from generating pulses when the pedal is kept pressed?


All this would be easy with a microcontroller, but noooo....  ]:)


No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

Grumpy_Mike


But how do I keep it from generating pulses when the pedal is kept pressed?

You wire the 555 up as a monostable, then you AC couple into it from your foot switch (attach it through a capacitor) then you will only get spikes that trigger the monostable when you press and again when you release.



szangvil

Using a micro controller will take all the fun out of it ;-)

Docedison

Fun... Hell man what you are talking about is hard work, the controller is easy

Bob
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

szangvil

It might be easy but if I want to make many of these circuits, it means I have to prepare an ISCP connector on my PCB and upload a sketch to each unit, which is time consuming.
I need it to be as small as possible since it needs to fit inside a foot pedal.

fungus


It might be easy but if I want to make many of these circuits, it means I have to prepare an ISCP connector on my PCB and upload a sketch to each unit, which is time consuming.


a) Soldering a dozen extra components to a PCB is time consuming, too...

b) https://www.adafruit.com/products/394

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

szangvil

In the long run, an assembly house would do that for me.

I really liked the pogo pins! Didn't know this solution existed :)

fungus


In the long run, an assembly house would do that for me.


If you're producing on that scale then the cost of the parts/fabrication should be #1 priority. I'm not sure which would win though, you're only dealing with switches and digital signals so a microcontroller is hard to beat. Atmel makes some really, really small chips for simple jobs like this (six pins).
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

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