Modifying Daito Ball dispenser for electric release

[Drunkenclam]

One of the final plans for my games room is to fit a ball dispenser to use on those machines that aren't CR ready due to age.
I picked up this dispenser last year, but never really wanted to use coins. After reading the spec Daverob had on his website and after a few discussions, I think its possible to connect the dongle/smartcard reader to a custom circuit board to either rechange a card or dispense balls at the push of a button.

After watching the mechanics of the dispenser I worked out what part needs to be activated by the solenoid, I stripped out the parts not needed, like the coin anti tamper,etc. I used super glue to fix the solenoid to the gear cover plate, so I can move and test it. Then drill and screw it into the correct place when done.
The solenoid pushes the horizontal bar down that releases the small gear on the right. The gear needs too turn for 2.5 rotations for 25 balls to be released. This is 1 rotation of the large gear. The solenoid needs to hold down the bar for over 2 turns but no more than 2.5 turns.

Now I'm not good at electronics but know a little. I brought a monostable timer kit from Maplins (Sort of a UK version of Radio Shack) Soldered it together and had a little play. The basic kit has a relay switch that changes status for 1 sec to 15min on an impulse. This is well out of the spec I need. I changed the 1k ohm resistor for a 100 ohm one, And changed the varible resistor from 1M ohm to 2.5K. This gives me an impulse time of between 0.1 sec to 2 sec (approx)

The relay controls a solenoid taken from an Adams Rite electric door release. This has approx 1/4" of travel.

After adjusting the varible resistor I got the timing just right. After constantly filling up and pressing the release button and counting.

Next step is to fit a low ball switch to stop the unit paying out if there isn't enough balls in it.


Too be continued...