IC: Jamma protector with voltage display, autofire, etc.

[kebrank]

Hello everybody,

Instead bumping an old thread about a Jamma protector "http://shmups.system11.org/viewtopic.ph ... ge+display" that went nowhere I decided to create a new one looking to recapture the interest and maybe find somebody willing to take this project forward.
I'm not an electronics engineer or anything like that but I'm positive this could be an easy project for the guys at arcadeforge or Villetim.

Some of the possible features:

- Voltage protection
- Voltage display (2 digits)
- Adjustable auto fire for all the buttons (3 each player)
- Test/Switch/Coin buttons

It would be easier to just make one model with all the functions instead a normal and deluxe models, to keep the project simple.
Any other ideas are welcome. I would add them to the list of possible features.

Thanks,

\o/.k.

[kernow]

Would the voltage display drain some of the +5 input and make it not as accurate or would it be adjusted to accomodate for it.

Sounds like a cool idea, not really needed for me but some peeps will buy it.

[PC Engine Fan X!]

I expressed interest in buying one in the older thread but the person making them/offering them hasn't updated as to whether or not it has been shelved or lost interest in it.

I'm sure with viletim's expertise, this nifty Jamma protector device would be a cool one to become a reality.

I'd like to have a couple for my candy cab and superguns, especially for the rare and really expensive PCBs -- don't want them to "bite the dust" but as with arcade power supply units, anything can happen these days (i.e. brownouts, blackouts, surges, etc.). But they're usual quite stable compared to the PC PSU powered superguns like that of Matt Ross' supergun setups. A few PCBs that I own were quite tempermental/bitchy if the voltage wasn't "right on the money," especially with an ST-V mobo. I already have my candy cab hooked up to a Monster surge protector strip for peace of mind.

PC Engine Fan X! ^_~

[emphatic]

Count me in as a buyer.

[kebrank]

kernow. That's a good question. I'm assuming it will consume some power but how much I don't know.
This is something that we have to make sure is fixed.
Thanks,
\o/.k.

[viletim]

I have quite a pile of projects on my plate at the moment, though I'll look into it when I get a chance. It doesn't look too difficult...

I would leave out the voltmeter display, however. It seems more of a gimmick than something which would be really useful. Most people who own an arcade cabinet also own a multimeter to take such measurements. There's no reason to drive up cost and complexity when the same outcome can be achieved by the smallest bit of extra work from the user.

[kebrank]

Well, imho the voltage display is handy. I have 2 cabinets and 2 superguns and I don't own a multimeter and the few people that I know with cabinets or superguns don't have one either. Besides, the multimeter would not be connected to the PCB all the time unlike the voltage display. So if by example the voltage moves up to 5.2v how would you notice it immediatly?. Same thing could be said about the auto fire, you can always play without autofire and just make a voltage protection PCB but it's handy and I think the idea behind the project is to come with a PCB that can do multiple things at a reasonable price so you don't have to buy a multimeter + auto fire circuit + voltage protection circuit + etc.

Thanks,
\o/.k.

[cools]

I have 2 cabinets and 2 superguns and I don't own a multimeter

:facepalm:

[THE]

If it's protection only and reasonable priced I would need 8 units.
With autofire and stuff, it maybe would be to much for each cab.

The other guy wanted to do 2 versions deluxe and normal. Maybe that's an option too? Starting with the normal version would probably make more sense.

And it's important, to test it with several Jamma connectors. My autofire circuit from Gfront or MAK does not fit directly on my Egret2s.

[viletim]

Well, imho the voltage display is handy. I have 2 cabinets and 2 superguns and I don't own a multimeter and the few people that I know with cabinets or superguns don't have one either. Besides, the multimeter would not be connected to the PCB all the time unlike the voltage display. So if by example the voltage moves up to 5.2v how would you notice it immediatly?

That is a poor example because it's not a likely failure mode. Switch mode power supplies generally fail in a predictable manner. If a power supply output goes high it would caused by a fault in the feedback loop - and this would cause an output increase in the order of 50 to 100%. It doesn't happen very often because this is a predictable failure and some extra circuitry (known as a 'crowbar') is often added to the power supply to short circuit the output if the voltage rises higher than it should. All ATX computer power supplies have a crowbar circuit, I would be surprised if it was not common among arcade power supplies also. Has anyone actually had a (properly connected) power supply destroy a game board before?

A voltmeter which is being powered by the power supply it is measuring is particularly useless because it cannot be relied upon to be accurate during a fault condition.

[undamned]

Would the voltage display drain some of the +5 input and make it not as accurate or would it be adjusted to accomodate for it.

A Voltage display circuit would likely draw less than 100mA. Your standard arcade power supply can source a terrible amount of current, so 100mA shouldn't even be a thought.

A voltmeter which is being powered by the power supply it is measuring is particularly useless because it cannot be relied upon to be accurate during a fault condition.

Haha, great point
-ud

[kebrank]

I just don't get it. So nobody here ever had a game that needed the voltage to be raised a bit?. Don't you think it it handy in that situation?. How can you put it back to 5v without a multimeter or a voltage display?. Maybe I'm missing something, is this so hard and expensive to make?. I had a supergun years ago that was built by somebody and had a voltage display and it was useful and cheap to make. Look at some of the arcade PSUs now, they also come with a voltage display.
Thanks,
\o/.k.

[brentsg]

I think a visual indicator of a needed voltage tweak would be fantastic. I don't tend to mess with it unless I'm significantly changing boards (diff type).

Sure it won't detect a fail condition but I don't think that's the primary function.

[cools]

http://wiki.arcadeotaku.com/w/Measuring_Voltages

[kebrank]

Cools, thanks for the link. I really didn't know about it. However, how big can be the difference between measuring the voltage at the end of the jamma harness and at the chip?. I'm pretty sure it won't be even 0.1 v. but I agree that the voltage displayed at the jamma protector PCB wouldn't be as exact as measuring it using the chip.
Thanks,
\o/.k.

[Dave_K.]

I would be interested in one of these as well. I've been toying with building one myself ever since havok1919 put up that thread, but I'm just a hacker, not a real engineer like viletim.

I think a voltmeter display is valuable, given I have a lot of machines and they are all tweaked differently, and I switch boards a lot. Even though I have a multimeter, I get lazy and don't measure the cab's often. I also think I've herd of failures in old Astro power supplies that destroy PCBs.

[PC Engine Fan X!]

Yes, viletim is, indeed, our resident techincal wizard capable of whipping up some cool gadgets for our candy cabs. I'd like to have a voltage display with my Jamma protector if it isn't too much trouble (and novelity factor).

PC Engine Fan X! ^_~