One of the more common problems faced by pinball collectors is where to put the next one. The thought came to me one day - what if I could re-purpose the pinball machine? I could then replace an existing appliance with the pin and my problem would be solved. With that in mind I converted my 1975 Bally Wizard into the most accurate clock in the house. And all I needed was an Arduino, A GPS receiver, an 8 relay board and some assorted odd bits.
Features: Pinball machine will automatically power up at the preset time each day and then resets to display the current time, the year, the time the alarm is set for and the date month/day. Then as long as the GPS has a signal the time will update once a minute for the rest of the day. At the time you would like to go to bed the Arduino will cut power to the game and it will remain off until the alarm time. Should you have a power failure in the night the machine will not lose it's settings. If power is restored prior to the alarm time the machine will wake up as normal, otherwise the machine will wake up once power is restored.
If the game is powered on because it is not yet bed time and it is after the alarm time then at 12am, 1am or 1pm the game will do a full reset. This makes sure the clock hasn't gotten off due to a stuck score reel, keeps the time in a 12 hour format and keeps the date display up to date.
The machine will automatically adjust for daylight savings time and leap years.
Cool features: The machine will automatically coin-up for any resets it needs - no need to have the game set on free play to do all of this. Powering off the clock (Arduino) will let you play the game as though no changes have been made to it.
Coolest features: When setting scores to the right displays instead of sequentially counting up the machine will advance the various scores randomly - slightly random timing and random scoring - and every so often listen for the occasional 500 or 5000 point score advances like you would get hitting a high scoring target. Looks and sounds more like a pinball machine being played, albeit quite a bit faster than most games, as it gets to the right display.
All this is done WITHOUT MAKING ANY PERMANENT CHANGES TO THE GAME. Take the Arduino and wires out - the game is as it was before you started without making a screw hole or soldering anything to the machine.
Disclaimers: I have seen the sparks these machines can generate and I have felt the flow of electricity through my arm. I have felt the tears run down my face when I have seen these same sparks come from under my Arduino when it has touched places inside the pinball machine it shouldn't have. If these things worry you, as they should, then know this - that is nothing compared to the reaction you will get when you get caught replacing a clock radio in the bedroom with a pinball machine. The atomic synced claim may be a little liberal - but the satelites I get the clock signal from are, so in a sense my pinball machine is now as well. It does have about a 1-2 second delay.
But seriously folks... The voltages in a pinball machine range from as low as 6 to full line voltage from the wall. Be careful in there. This is probably not the best thing to do if you have never played around inside a pin before.
Arduino. I used an Arduino Duemilanove but an uno should work as well $25-$30
8 relay board/shield. picked this up on e-bay for less than $20
GPS receiver (as found in Microsoft Streets and Trips) $20 - $30 on ebay
Long length of cat-5 cabling (cat-5 is what I used, but you just need to get three wires from the GPS by the window into your pinball machine) $10
Jacks to connect the cat-5 cable. $5
Headers and connectors like the kind you that you would find at the same place you picked up your Arduino $3
some aligator clips and wire. $3
A blown fuse from a pinball machine $0
Power for it all - an old PC power supply $15
An electro-mechanical pinball machine (and a schematic diagram just to be safe) $150-$2000
I am just guessing about some of the prices as I happened to have a GPS, cat-5 cable, rj-45 connectors and a pinball machine. All I really needed to pickup was the Arduino, the relay board and some odd bits to finish it off.
When I built this I used a Bally Wizard. The code for the Arduino should work for almost any four player Bally game from that era without too much tweaking required. It shouldn't take much at all to adjust things around and make this work on almost any EM pinball machine you just need to take into account what switches will advance the score to the next player and if the game scores a bonus at the end of each ball.