🚀 go-pugleaf

Some friends are having trouble controlling an AC actuator.
They tried using a TRIAC driver (ie optocoupler) to drive
the TRIAC, which was to briefly switch on an actuator.

The setup usually worked, but occaisionally it didn't appear
to provide enough current to drive the actuator

In case this helps: they made a microprocessor controlled
keypad for a vending machine, in this case an old Coke (bottle)
vending machine. The actuator is supposed to advance a mechanism
that allows you to pull the bottle out. The digital stuff works
fine: it polls a keypad for a user's "account" and password, then
it deducts from the account, and then sends the "vend" signal.

In software, they tried enabling the triac driver for longer periods
of time, but this didn't seem to work any more reliably.
Next they used a relay, and this worked a lot more reliably, at least
vending, so now people get their bottles out of the machine when
they enter their password, but now the problem is slighlty worse:
occasionally on a transient on the power supply (especially when the
refrigerator motor switches off), the relay reacts and gives out
freebies occasionally!

IN summary: the triac/triac driver combo occasionally didn't drive
the actuator properly, ie not being enabled when it was supposed to.

the relay set-up occaisonally enables the actuator when it is not supposed to.

I can't get more specific about the actuator we are trying to operate:
this "vending machine account system" is retro fitted onto an existing vending
machine. Gauranteed it is an inductive load. They could try and measure it.
It operates on 120VAC, and normally only need  120VAC for about 0.5 seconds
(actually less).

Any help would be appreciated: this system works pretty well 90% of the time,
it just glitches now and then (not exactly disastrous given the purpose!)

If your wondering why they built it: it's a great additition to a pop etc.
vending machine you would have lying around an undergraduate club, or fraternity
where you have enough people buying stuff from the club on a regular basis,
that you can either pre-sell stuff (they get an account) or they buy on credit
(they pay at the end of month/term etc).

jpm