Slot Machine

I remember when I was a 17-year-old, recent high school graduate, and was traveling with my grandparents from California back to their home in Michigan. Of course we stopped in Las Vegas and walked the Strip just to see what there was to see. Almost all of the casinos were open at the front so I wandered into one with my grandparents. I saw a nickel slot machine and just had to stick a coin in. Surprise, surprise, I hit the jackpot! Jackpots were paid out as two rolls of 50 nickels each so a casino employee came over when the lights and sound went off. He looked at me, handed the rolls to my grandmother and quietly told her that anyone under 21 really wasn’t supposed to be in there.

I like technology but I’m not a tech junkie by any means and I also like a lot of “old school” stuff like antiques, cars, etc. For instance, if I ever decided to buy a pinball machine I’d want one from the 60’s or 70’s before they got too glitzy. I’m also not a gambler but I remember how cool that old time slot machine was. Just for fun I decided to check some out on eBay and about fainted when I saw the price tags. I could probably afford it but I’m too cheap and there’s no place in our home for it anyway. Still, I thought that the young grand kids might enjoy a toy like that when they come to visit so I decided to see if I could build a small version.

Components

Old time slot machines had three windows and mechanical wheels with a variety of images that would spin behind the windows when a coin was inserted and the side handle was pulled. The spinning wheels would come to a stop one at a time and some sort of payout would occur for various matching images. They also tended to have flashing lights and noise if a jackpot occurred. I wasn’t trying to exactly recreate an actual slot machine but at least it had to have some of the basics. I needed a solenoid to activate the trap door for the coins when a jackpot occurred and some LED’s for flashing lights. I also wanted some sort of sound so I found a sound recorder module in my junk box and recorded the ever popular phrase “Winner, winner, chicken dinner”. It plays through a small speaker.

The display is one of the large digit surplus 1601 LCD’s that I have lying around. I used square bracket characters to simulate three windows and finally decided to just use numbers instead of characters for the “tumbling” wheels. I added a small buzzer to make a clicking sound while the digit “wheels” were turning. I hemmed and hawed about whether or not to trigger the “spin” when a coin was inserted or to build a separate handle. The coin slot I bought came with a coin reject button so I decided to use that to start the spin. I mounted a micro switch so that it is activated when the coin reject button is almost fully pressed. A piece of scrap PVC pipe was placed between the coin slot and the trap door to hold the inserted coins.

A big part of the fun was doing a little woodwork (one of my other hobbies) to build the cabinet. I didn’t have anything that was quite right in my scrap pile so I headed to the local lumber store to look around. One of the types they carry is poplar which, to me, sounded pretty bland. But when I started sorting through boards I came across one that I just had to have because of its variety of color bands. It was only later that I found out that it is an example of what is termed “Rainbow Poplar”. Unfortunately, my photography doesn’t really do it justice.”

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