Here is how to modify the S+ bell circuit for other uses

[poppo]

In a few threads there has been talk about using the bell circuit to operate other things, but I did not find any specifics or actual projects. In my case, I want to have some sort of audio-visual thing for big hits. The first thing I did was change my limit settings for hand payouts for the top 4 awards. Leaving the bell output set for hand payout only will give me the desired results of only activating for those top hits.

Now, I have found a few posts talking about using the bell output to operate a relay to turn something else on instead. That is a good idea and one I will use. However one mistake I have seen in most of those threads is stating that the bell output is 24vdc. It is not dc, it is 24vac. I know some of the bells say 24vdc on them,  but the machine is actually outputting AC as will be shown below.

After looking though the schematics, I see that J11 on the motherboard has 2 pins for the bell. Pin 1 is 24vac hot (meaning there is always 24vac there) and pin 2 is a switched ground. This ground is applied though solid state relay K8 on the MPU when the bell is activated.

So what does this mean? It means that we don't actually have to use the 24vac at all. All we really need to care about is that switched ground.

In the first photo I am showing the measurements of J11 (the bell output) doing a bell output test. As you can see I am reading 24vac as expected.

In the second photo, I have plugged a 12vdc wall wart into the front outlet. I tied the ground wire (temporarily for this test) to the BV chassis which is ground for the whole machine. Next I measured the voltage from the positive lead of the wall wart to the switched ground of the bell output while doing a bell output test. As you can see I am now reading about 13vdc (normal for a 12vdc wall wart with no load). All that is happening is the solid state relay K8 is completing the ground circuit. Note: You can see the 24vac hot wire just laying there not connected to anything.

So, the bottom line is that all we really need is that switched ground and we can use any power supply we want to turn on whatever we want. I still plan to use it to turn on a relay, but finding a 12vdc relay is easier than a 24vac one. Unless the relay is designed for ac, the contacts can 'chatter' during the zero crossing of the ac voltage which can cause undesirable results.

As I noted in another thread, I have a small siren kit. My plan is to have a relay that will disconnect the slot machine speaker during one of those hand pays and connect the siren to it instead. By disconnecting the speaker from the slot output, I won't have to hear the 'attention' dings, and can use the same speaker for the siren. Another set of the relay contacts will turn on the visual effects which I have not yet decided on. I'll document this project here as I go along in case anyone wants to do something similar.

[poppo]

I always try to use parts I have laying around. So I found an old power supply that outputs regulated 12vdc at 1.5 amps and 5vdc at 1.5 amps. I figure this will give me plenty of power and voltage options.

Next I found an old 12vdc relay board. This was originally designed to be driven from a computer parallel port, but I had modified it for something else. Now I have modified it again for this project. Normally it has 8 independent relays. But for this project, I just wired up the first two to turn on when power is applied to the board.

As I showed in the previous post, I have tied the ground of the power supply output to the slot chassis which is ground. I connected the +12V to the relay board power in and the switched bell ground to the relay board negative input. Now whenever the bell would be activated, so are the relays.

I then connected the 5v output of the power supply to the common connection of relay #1 and the NO contact to the positive input of the siren kit. I have a speaker temporarily connected to the siren kit to test things. Later I will tie it into the existing speaker.

Keeping in mind this was just a kludge I threw together in about a half hour, here is a video of it in action using the bell output test.

<a href="http://www.youtube.com/v/9CAPM1RaI3I&rel=0" target="_blank">http://www.youtube.com/v/9CAPM1RaI3I&rel=0</a>

[Frank A]

Quick question... If LED lights or any lights can be found at 24 VAC, would it be possible and safe to connect the LED or any other 24 volt lights to the bell wires so that the lights and bell are energized at the same time ? Am I going to burn something out if I don't use a relay ?

[poppo]

Quick question... If LED lights or any lights can be found at 24 VAC, would it be possible and safe to connect the LED or any other 24 volt lights to the bell wires so that the lights and bell are energized at the same time ? Am I going to burn something out if I don't use a relay ?

As long as whatever you plan to use will run safely off of 24vac, you will be fine. I don't know how much total current that bell line can supply though since it is also used to power other things. The standard bell says it draws .18 amp so anything under that should be fine. If you wanted to ADD something to an existing bell, I would be very leery of doing it.  

Keep in mind that K8 on the MPU is a solid state relay. This means that a very small amount of current will flow though it even when 'off'. So it is possible that a very light load such as a single LED may light up, or light up dimly even when it is not energized.

Personally, I would use a relay even if you resort to a 24vac one, and a separate power supply for the other items you want to power. It is always best to isolate things to prevent any chance of  

[poppo]

After closing up the top of the cabinet, I like the sound of the siren speaker up there. So instead of switching the siren sound to the slot speaker, I will use the second relay's NC contacts to just disconnect the regular speaker during bell activation to 'mute' the attention dings you get during hand pay.

[stayouttadabunker]

Poppo,
That open socket on the left side of the relay board you have...
Could you install a timer chip there so the relay could be turn off after
a programmed amount of time without resorting to the Jackpot reset key?

I was wondering about that because you were asking in the other thread about
whether or not you could program how long the bell would ring?

Or is that socket for something else?

[poppo]

Poppo,
That open socket on the left side of the relay board you have...
Could you install a timer chip there so the relay could be turn off after
a programmed amount of time without resorting to the Jackpot reset key?

I was wondering about that because you were asking in the other thread about
whether or not you could program how long the bell would ring?

Or is that socket for something else?

That socket was for the buffer chip to turn on/off the relays. As I mentioned, this was originally designed to use a PC's parallel printer port. With some software, it would drive the 8 data lines high or low to turn on/off individual relays. I just pulled it out and manually grounded the outputs to always enable the first two relays.

While it is certainly possible to add a timer, that socket would not work well for it. In that other thread, I was actually glad to hear that it would stay on during a hand pay, as that is the effect I wanted.

Since I always have the reset key in the switch, it's a simple matter to shut the machine up after it goes off and I get tired of listening to it. I realize that my implementation of the hand pay on certain awards may not work for everyone. Mainly I just want to show people how to do other stuff with the bell circuit.

I ordered some cheap multi-color 'hockey puck' led flashers. I am going to try mounting a few somewhere in the cabinet by the reels. With any luck, I will get a multi-colored light show inside the reel area when the bell would go off. Not sure how well that will work, but I have some other ideas too.

[Frank A]

Thank you. I am afraid to add anything for fear of burning out the board. One of our members fried a board by replacing a lamp with an LED that was not compatible.

[poppo]

Thank you. I am afraid to add anything for fear of burning out the board. One of our members fried a board by replacing a lamp with an LED that was not compatible.

It may have been something different, but I believe that problem was how the LEDs had the power leads attached and that they would short out the lamp socket and thus fry a trace on the board.

If anyone wanted to use the bell voltage directly, they could always put an in-line fuse on the wire if they wanted to play it safe. A 1/4 amp fuse would probably be a safe bet.

Although I am not using the 24vac line, I still need to be careful on how much current I draw through that switched ground line. I would probably give it the same 1/4 amp rating. Another reason to use a relay no matter which approach one takes.

[poppo]

So I spliced into one of the speaker wires and ran the lines up to the relay board. Got everything connected and closed it up. I wanted to test it, so I was going to set the hand pay to like 9 so that a small hit would trigger everything. I had about 70 credits on the machine and I was running them down to make the limit change as I was cleaning up my mess. I had just hit the spin button and turned around to cart off some more stuff when I hit triple mismatched 7s (5th award from top). The siren went off and it scared the bejesus out of me. On the plus side it did exactly what it was supposed to. The siren was going but no dinging from the regular speaker. After I get my light show parts, I'll make another video of it.

[poppo]

Instead of reposting the video, here is the Bulls-Eye thread where I added some strobes in post #24.

http://newlifegames.net/nlg/index.php?topic=10976