What's new

24vac pulses question

Mohrenberg

New member
Joined
Dec 14, 2020
Messages
24
Reaction score
21
Points
3
Does anyone know if the pulse coming off a coin acceptor can be observed on a multimeter, or even by hearing the click of a solenoid or relay plugged into the output wires?

I'm tinkering with some hardware I'm building, but all I've got.on hand is two old idx ma800 acceptors, and I've been unable to measure anything coming from them during a pulse. So I have no idea if the pulse is too fast that I'm not detecting it or if my coin acceptors are defective?

I have tried triggering a 24vac solenoid, also tried triggering a 24vac relay (which has a view window to see the switch physically move, and it doesn't at all)

I've even tried using a bridge rectifier to convert the 24vac pulse to dc to power an LED with no luck.
 

MEP001

Well-known member
Joined
Aug 30, 2007
Messages
16,667
Reaction score
3,933
Points
113
Location
Texas
I use a 24VAC pilot light to test coin acceptors. With an MA800 you have a relay output, so you can use any voltage you want through the two red/green wires. I don't recommend trying to power a solenoid since even the smallest ones draw 7 watts and might damage the relay.

A cheap voltmeter may not show the pulse. A good one will display the peak output - mine doesn't update the display very fast, but it will display 24V from a coin pulse because it will display the peak of a very short pulse. Another option is a really, really cheap voltmeter with an analog (needle) display.

Knowing the MA800s, it wouldn't surprise me if yours are both bad.
 

Mohrenberg

New member
Joined
Dec 14, 2020
Messages
24
Reaction score
21
Points
3
Also, I know I have power from the transformer, I can power everything straight from it, and I've programmed the coin acceptor.
It maintains. Green light, and a quick red flash when I insert a coin.
 

Randy

Well-known member
Joined
Sep 5, 2007
Messages
5,625
Reaction score
1,910
Points
113
Also, I know I have power from the transformer, I can power everything straight from it, and I've programmed the coin acceptor.
It maintains. Green light, and a quick red flash when I insert a coin.
By maintaining the Green light on the side of the coin acceptor and the flashing red light when you insert a coin doesn't necessarily mean the coin signal is coming out of the coin acceptor. The standard coin signal pulse rate is 50ms. What are you trying to build?
 

Mohrenberg

New member
Joined
Dec 14, 2020
Messages
24
Reaction score
21
Points
3
By maintaining the Green light on the side of the coin acceptor and the flashing red light when you insert a coin doesn't necessarily mean the coin signal is coming out of the coin acceptor. The standard coin signal pulse rate is 50ms. What are you trying to build?
Capturing the pulses and transmitting them to my website for real time monitoring and analytics.

I think I'll just go ahead and order my new coin acceptors so I can rule out that being the problem.
The car wash hasn't ran in a decade so these may just not work.
 

Mohrenberg

New member
Joined
Dec 14, 2020
Messages
24
Reaction score
21
Points
3

Here is a test circuit I was using after I was unable to detect it digitally (checking tens of thousands of time per second for a pulse) just incase I was missing something.

But it works fine with power directly from the 24vac transformer, just nothing from the coin acceptor pulse.

I didn't know anything about that pulse so came here looking to confirm that it's probably just a bad coin acceptor.
 

Randy

Well-known member
Joined
Sep 5, 2007
Messages
5,625
Reaction score
1,910
Points
113
Before I bought new coin acceptors I'd verify that the coin acceptors I'm currently using for testing are defective by connecting them to a vac or bay timer.
 

Mohrenberg

New member
Joined
Dec 14, 2020
Messages
24
Reaction score
21
Points
3
Before I bought new coin acceptors I'd verify that the coin acceptors I'm currently using for testing are defective by connecting them to a vac or bay timer.
I planned to buy new coin acceptors for the rebuild anyways, I'll just buy them earlier than planned so I continue with this project.
 

MEP001

Well-known member
Joined
Aug 30, 2007
Messages
16,667
Reaction score
3,933
Points
113
Location
Texas

Mohrenberg

New member
Joined
Dec 14, 2020
Messages
24
Reaction score
21
Points
3
You might want to look into something like this:

Interesting, but no fun just buying it.
I'm just getting into electric stuff, but I enjoy programming so making the website to analyze the data will be a fun project.
 

Mohrenberg

New member
Joined
Dec 14, 2020
Messages
24
Reaction score
21
Points
3
What coin acceptors are you looking at for this project?
No specific brand, I'd like to have it work on any pulse that a bay timer would be able to pick up.

I planned on buying slugbusters for my car wash. It's a small 2 bay self serve in a rural town of 500 people.
This is just a side project I started playing with because I thought it would be cool to track all the self serve sales remotely in real time, by using existing self serve equipment. I just got the building gutted and have started the rebuild, so I was still a little bit away from ordering new equipment, so I'm just going to order the two coin acceptors a little ahead of time.
 

Attachments

Mohrenberg

New member
Joined
Dec 14, 2020
Messages
24
Reaction score
21
Points
3
I bought this property for the storage units.vi had initially planned to just tear down the car wash and sell the steel building frame, but it turns out the entire thing is welded together, built in 1978. So on a whim I decided to just rebuild the car wash.

I program as a hobby, and recently got into Arduino, so I figured this could be a fun and useful project. For about $50 in parts I could know when customers use the car wash, how much they spend, what features they like, how much time they're spending on each function, I could even send myself automated text messages letting me know my coin boxes are probably close to full 🤷

It's my idea of a good time, and I like learning.
 

MEP001

Well-known member
Joined
Aug 30, 2007
Messages
16,667
Reaction score
3,933
Points
113
Location
Texas
FWIW there are two basic types of coin acceptors, those that only output a 24VAC pulse and those that have the relay circuit like the MA800 you've been working with which you can use with any voltage. Just mentioning it if it helps in your choice. Slugbusters are in the former. Also FWIW, I've been getting dollar coins in my safes that are getting through Slugbuster II and III and jamming my changer. It's a problem because I just dump the coins from the safes straight back into the changer.
 

Dan kamsickas

GinSan Technician
Joined
Aug 31, 2007
Messages
588
Reaction score
677
Points
93
Location
Grand Rapids, MI
Before you can build any type of sensing circuit you have to know the input voltage of the timer you are hooking it up to. Some timers have a 24VAC input voltage, some an 8VDC input voltage, some a 12VDC input. Some are referencing 24 hot, some are 24 common. All any coin acceptor in this industry does is short out that input voltage at the timer. Years ago we had a data acquisition system we sold called the Datamate(technology bypassed it). The constant battle was tying to match the impedance of our inputs to the various timers that were around. We actually had different interfaces(some transistor based, some triac, some SCR, some relay) to accommodate all the different setups. There are far fewer timers around now but the issue stays the same. Perfect example is Dixmor LED7s and LED6s reference opposite sides of the 24 volt supply for their coin input.
 
Top