The machine pays out in balls, the size of the win being the lowest digit which appears on the three reels (so any combination which contains a zero is a loser).
During the building of it much was learned about K'Nex (Elap had discovered it at a car boot sale only a couple of months before he started) and some PDFs on K'Nex have been produced (see below).
The non-K'Nex bits of the fruit machine are the reel symbols (produced using Microsoft Word and then laminated) and the balls (meant for a child's play pit - Elap didn't have anywhere near enough K'Nex balls, and they are expensive). Also, a weight has been made from a lead-filled K'Nex cage because there were no K'Nex components which were heavy enough.
It probably took about 150 hours to build, spread over two years, and was made up as it was built - there were no plans, but Elap collects old mechanical slot machines and was familiar with the principles. There were a few areas where a redesign was necessary (for example, the handle kept falling to pieces when pulled, and the original pawl and ratchet mechanism was clunky and didn't work very well), but there wasn't a lot of reworking overall.
The return is 85.94% - quite generous for a fruit machine!
The K'Nex pieces were acquired from car boot sales (mainly) and eBay.
Here are some documents relating to the construction of the machine, and some K'Nex tips.
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It would be too much work to explain what I did, and I've forgotten a lot of it!
HOWEVER, I'm experimenting with a smaller version which would use K'Nex ratchets and K'Nex rubber bands and would work with K'Nex balls.
If I succeed, I'll produce step-by-step PDFs, but to be realistic it would be the middle of the year before - and if - I completed it.
The larger the machine the more feasible it is. For example, If you want a combination of rods to be a certain length, there are far more combinations of rod lengths to try for a large-scale machine than with a smaller one.
It would be a big challenge to make a smaller version without modifying the pieces, which of course is not allowed!
The reason the machine is the size it is is based on constructing the smallest reels which used eight flexible rods of the same length.
Having said all this, I have an ongoing background task running in my brain on how to make a smaller version...
My mouth fell open...
But im wondering, how do you make the wheels spin?
The handle attached to the wheel?
A quick running motor?
A weight on the wheels?
Something else?
Also, how are you stopping the wheels exactly at the good spot?
I'll reply more fully within the next week or so.
That is so smart,
Thanks :D
I could show you how to make the reels, and how to install them in a frame. I could then show you the principles involved, but because I made it up as I went along I couldn't give you step-by-step instructions (I only discovered the Instructables site after I had finished it).
A smaller version would be much more difficult - there would be fewer ways to make each element of the construction because you are constrained by the number of combinations which could be experimented with.
Also, it is occasionally necessary to reach into the innards of the machine which would not be possible if it were smaller - bits of it would have to be disassembled first.
Let me know whether you want more photos so that you can see various sections in detail. Bear in mind that you will need to be an inventive kind of K'Nexer to build something like this and not just an instruction-follower!