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    element14's The Ben Heck Show

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    The Ben Team does a rebuild and repair of a vintage Japanese Pachinko machine!  Using a "Prop Dev Stick" microcontroller, a single board audio amplifier, 2N4401 NPN transistors, repurposed speakers, and lighting; they do a refresh of  this 70s era classic gambling machine; complete with  lights and sound effects!  Which build would you kickstart?


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    Pachinko machines are common gambling games which are played in Japan, and are still in use today!  Before bringing the Pachinko machine into the modern era, Ben and Karen need to figure out how the machine works and give it a cleaning. For example, the launch arm doesn’t work unless enough balls are loaded into the Jackpot hopper. Their plan involves using switches to detect different states in the game such as success or failure.

    Ben uses a low force micro switch attached to 3D printed parts to allow sound effects to be added and to detect every possible state of the machine. The machine will have lights as well as sounds.  Ben grabs an Atari jaguar power supply, a single board audio amplifier, a “Prop Dev Stick” microcontroller that can do audio and has an SD card built into the board.  Ben adds external circuitry to the microcontroller by wiring up a bank of transistors so that they can control higher power lights using the lower power microcontroller.

    Ben uses a bunch of 2N4401 NPN transistors and does a test to see if he can pump 12 volts into the lights and control it with a 3.3 volt microcontroller. He uses bayonet style 44-42 bulbs rated at 6.3 Volts and duty cycles them so that they are only on half the time. This will allow them to work properly without being burnt out. Ben hooks up six transistors and six ports to the PCB to allow lots of options.  He also uses a regulator to step down from 12 volts down to 3.3.

    The 12 volt input is the same thing that goes to the audio amplifier.  There is a capacitor for filtering that.  There are transistor controls for six lights.  The transistors are hooked up to the microcontroller.  The 5 volt regulator takes a 12 volt max and knocks it down to 5 Volts before going to the microcontroller board. The audio output jack also goes to the audio amplifier. There are also four switches hooked up to the PCB: ball load good switch, good launch switch, jackpot switch, and drain switch. Ben mounts the PCB to the plastic on the machine.  He then wires up the lights and the switches.

    The Panchinko machine will include a system on light, a ready light, and jackpot lights. Once the lights are set and the rest of the logic is working, a selector is added for different sound effects.