Coin acceptor, CH-926
The programmable coin acceptor: a chrome face with a coin slot and a return lever, and a four-wire harness. Aliases: CH-926, multi coin acceptor, coin slot.
It is taught up to six kinds of coin by sample, and told how many pulses each one is
worth. A coin it knows drops through and COIN sends that many pulses; anything else
falls out of the return. So the board never learns which coin it was, only a count.
Pins
| Pin | What it does |
|---|---|
DC12V |
The 12 V supply, the red wire. |
COIN |
The pulse output, the white wire. Open collector: it pulls to GND for each pulse. |
GND |
Ground, shared with the board. |
COUNTER |
Drives an external counter on a real one. Not connected here. |
Properties
pulse is the length of each pulse in milliseconds, 50 by default, with a gap of the
same length after it. The speed switch on the back of a real one sets it; match the
two. nc flips the output: the line is held low and released for each pulse, as the
NO/NC switch at NC does.
While it runs
Click a coin under the face to drop it in. They are worth 1, 2, 5 and 10 pulses, the way a piggy bank build teaches them for 5, 10 and 25 cents and a dollar. The readout counts the pulses, and the slot glows while one is on the wire.
What the model gets right
The supply. Under 10.8 V (12 V less 10%) it is not running, and a coin falls back out.
The output. An open collector, so COIN needs a pull-up: INPUT_PULLUP on the
board, or a resistor to 5 V. Never to 12 V.
Coins in a queue. A coin dropped while another is still sending waits for it to finish. Drop them a moment apart: two clicked at once follow each other by a single gap and read as one long burst.
What it does not model
Teaching the coins, which happens on the unit's own buttons; the inhibit input some versions have; and the time a real one takes to look at a coin.
Common mistakes
Powering it from the board's 5 V. It needs 12 V, with the grounds joined.
Counting a coin per pulse. Count the pulses in a burst, then decide what the burst was worth once the line has been quiet for longer than a gap.
See it in action
Piggy bank counts the money on a TM1637 display. Open it at /templates.