Build Your Own Arcade Controls Forum
Main => Main Forum => Topic started by: Trimoor on October 13, 2004, 03:05:53 am
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I would like to build a circuit so that when a SPST toggle switch is closed, it will illuminate an led, and hold down a button on a keyboard encoder.
The KE is like any other, pull the lead to ground to trigger a keypress.
I think this could be done with one or two transistors, but I can never get them figured out.
No relays please! (They suck way too much power.)
Thanks all.
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Here is a really simple diagram. The wavy line is a resistor to fit the led. This is with the understanding that the encoder expects the input to be grounded when the button is pressed.
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someone else may correct me, but i think just putting a small capacitor inline with the switch will give it a momentary 'on'. Peale will have more info there as he was using a capacitor for his start-up switch which also needed a momentary 'on'. see the sketch. the LED part of my sketch im not 100% sure about since i don't know how much current a KE can draw, even though the LED (which may be drawn back-to-front in my sketch) draws hardly anything.
i'm sure someone else can verify whether this will be ok. if not, then a double pole, single throw toggle will do the trick by keeping the LED circuit completely seperate from the key circuit. this keeps the complexity of the whole thing nice and simple (",)
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hehe. just noticed that justmichael drew the same thing!! i assumed you wanted a momentary 'on' and he has assumed you want a hard 'on' (excuse the pun :o).
the only difference is the capacitor for momentary on. you're choice!
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Thanks, I'll probably use JustMichael's version.
I don't need a momentary press.