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Main => Main Forum => Topic started by: mahuti on November 05, 2020, 07:18:10 pm

Title: Q-Bert Knocker wiring to LedWiz
Post by: mahuti on November 05, 2020, 07:18:10 pm
So this has been covered before to a degree, but I still need a bit of help.

I plan to wire up a Q-bert knocker to work with MAME's output system. I'm using an app that captures the output, and signals to the LEDWiz. I can figure out enough to wire up the knocker with a relay from Led-Wiz. The app *should* signal to the LEDWiz to deactivate the relay, but I don't want to count on that, I don't want the coil to stay energized. So I need some way of setting the relay to trigger and release rather than stay activated. I need a failsafe.

I'm not set on the relay, that was just my first line of thought until I realized that there might not be an "off". I don't know enough about transistors to even figure out what to buy, or what else I'd need with it.

This is the knocker:
https://www.arcadeshop.com/i/1125/q-bert-knocker-assembly-with-12v-coil.htm

I've got a typical arcade power supply, a fuse holder, a pile of a variety of fuses collected over many years of arcade stuff, a small amount of sense, and great soldering skills. Any help would be greatly appreciated.



Title: Re: Q-Bert Knocker wiring to LedWiz
Post by: baritonomarchetto on November 06, 2020, 02:19:18 am
If your concerns are about the kind of signal your app sends when a "knocker on" signal is received from MAME, connect a led instead and see what it does (obviously you will need 5V/12V and an adeguate resistor in series to the led). It's likely that the app has a test monitor and can show you the signal flow anyway.
I suppose it's mamehooker. If not, use it instead.
Title: Re: Q-Bert Knocker wiring to LedWiz
Post by: mahuti on November 06, 2020, 04:42:03 am
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I suppose it's Mamehooker 

Its not. I'm using LEDSpicer.

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  If not, use it instead

How does Mamehooker install on Linux again?  ;)

Seriously though, thank you for the suggestion, I'm with you on that already. I currently use LEDSpicer to manage LED signals being output by MAME; led1=on, led1=off. That works fine. If I install a knocker though, its not a hold-open solenoid, so I don't want to count on the software 100%, since leaving it open could cause it to burn out pretty quickly.
Title: Re: Q-Bert Knocker wiring to LedWiz
Post by: baritonomarchetto on November 06, 2020, 06:19:03 am
Ok ok, I missed the linux thing :)
If you don't trust the program or it does not work the way you need and you are not able to modify the surce code, place a microcontroller to monitor the signal to your relay and shut it in case of a too long active time.
This would be super cheap (and super easy) with an arduino board.
Title: Re: Q-Bert Knocker wiring to LedWiz
Post by: mahuti on November 06, 2020, 01:35:28 pm
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If you don't trust the program or it does not work the way you need and you are not able to modify the surce code

I trust it, and I can modify the source, but solenoids aren't intended to stay energized very long, so if, for instance, there's a software crash while the solenoid is open, the solenoid will stay on and blow.

An arduino could do the job, it just seems like a few resistors, capacitors, diodes and a transistor would do the same cut-off job in hardware form.