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Your not going to get a much simpler circuit. It is using just one of the 6 gates found in either a 4049 or 4050, depending on whether you require switching to low or high), and a handful of passive parts.

 

http://www.labbookpages.co.uk/electronics/files/debounce/debounceCircuit.png

 

Your time is set by the value of C1 and R2 however for really small delay periods, as CMOS chips always have a small resistor already on the inputs, you can do without R2.

 

Yes, That is the classic debounce. You can also invert it with a simple transistor.

74hc221_InvertDebounce.png.b88fc1f56302637f4583e53ff1c0fee1.png

 

- - - Updated - - -

 

I don't want to be pedantic but in regards to the 555

Circuit you are wrong, all pulses inside the timed output window are ignored.

The circuit wasn't handed over in speculation that it might

work it actually works.

I have used this circuit mainly for pop bumpers in several pinballs.

Also a 555 can drive a relay or power Transistor without a buffer circuit...don't underestimate the mighty 555

 

Do be pedantic, I thought they were re-triggerable.

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You can also invert it with a simple transistor.

[ATTACH=CONFIG]112841[/ATTACH]

 

Some helpful notes about this debounce circuit.

I use the inverted version - So I like to limit/sink @1mA (Hence the 5k resistor @ R1)

 

For ease of use (Lazy), I substitute capacitors for approximate timing.

1.00uF = ~40mS

0.47uF = ~20mS (Recommended for general use)

0.22uF = ~10mS

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  • 2 weeks later...

To Plug or Not to plug ,that is the question ? I was having a discussion with one of our fellow AA members the other day on whether its better to put plugs on boards , or just solder all the interconnections?

I'm a Pluggist ! I like to plug !

Upside . Easy to remove a board to bench test or repair. Very handy in homebrew as a board may alter a few times in its evolution.

Downside: Lots of plugs to fit off, chances of high resistance or bad connection, plugs can work loose at times.....

But, have a think I say ! Today I had a couple of issues with my rollover controller board. This little critter is 3 Boards all working in harmony ( or not ). If this was soldered and interconnected to all the other boards, it would have been a lot of trouble to fix it in the machine. But with a few deft un-pluggings, it was out and its issues found and fixed !

So thoughts?

Oh here's a pick of the board, there are 59 Individual wires running to this board alone ! Note on the base processor board and BCD decoder are shown, the BCD encoder board plugs in on top of the processor.

IMG_7987.thumb.jpg.ffe5154462f3f675cff2eaf8823aea67.jpg

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To Plug or Not to plug ,that is the question ? I was having a discussion with one of our fellow AA members the other day on whether its better to put plugs on boards , or just solder all the interconnections?

I'm a Pluggist ! I like to plug !

Upside . Easy to remove a board to bench test or repair. Very handy in homebrew as a board may alter a few times in its evolution.

Downside: Lots of plugs to fit off, chances of high resistance or bad connection, plugs can work loose at times.....

But, have a think I say ! Today I had a couple of issues with my rollover controller board. This little critter is 3 Boards all working in harmony ( or not ). If this was soldered and interconnected to all the other boards, it would have been a lot of trouble to fix it in the machine. But with a few deft un-pluggings, it was out and its issues found and fixed !

So thoughts?

Oh here's a pick of the board, there are 59 Individual wires running to this board alone ! Note on the base processor board and BCD decoder are shown, the BCD encoder board plugs in on top of the processor.

[ATTACH=CONFIG]113968[/ATTACH]

Plug and play all the way.[emoji6] Especially when prototyping gear like we are.

A lot of the problems with connectors in machines are due to the age ie; corrosion, loose connections and broken wires due to repeated plugging and unplugging over the years.

As you say for convenience you can't go past connectors.

 

Sent from my SM-G930F using Tapatalk

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Plugs yes but trying to keep the plug connectors to a minimum is always my intent.

 

For low power multi circuit connectors, I like to use IDE connectors because they allow the board to be smaller and ribbon cables just look a lot neater than individual wired connectors.

 

Power supply cables to a board, I like to solder the wires direct to the board and have inline connectors in the wires to the board.

 

It allows for disconnection, keeps the high current cables away from the low current, signal wires but because it is inline connected, if you need to supply more devices at a later stage, you can just add in another connector inline rather than needing to pull the power off the original board.

 

I also like to have power indicator LEDs on the board so you can easily see if the board is actually getting power to it.

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I'm trying to get plugs and sockets down to the one that plugs into the wall.

Connectors mean points of failure in my opinion.

That being said if one was to go into manufacture plugs and sockets are a given, for a

homebrew one off NFW the less the better.

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yes off topic....too off topic then admin please move to the....bin? not that this would be common but connectors, the pins, male, female whatever tin/zinc/nickel etc are electroplated and aren't wired up individually, they are electroplated in a barrel, thousands at a time and depending on who is doing the job at the time can result in a leftover 'residue' on them due to improper washing/rinsing. Ideally a final rinse wants to be pH neutral but when doing load after load even with fresh water constantly being added to the rinses there is more than likely carry over of prior rinses/solutions. Also polishing circuit boards like bakelite ones in EM's for example will leave a 'coating/film' on the faces of silicon may be depending on what polish you are using, yes they look all shiny and new but you may want to consider using metho or similar to remove anything that might cause resistance between contacts.
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Also polishing circuit boards like bakelite ones in EM's for example will leave a 'coating/film' on the faces of silicon may be depending on what polish you are using, yes they look all shiny and new but you may want to consider using metho or similar to remove anything that might cause resistance between contacts.

 

EM boards actually come from the factory with like a grease film on them.

 

I suspect it was contact grease. They certainly were not bright and shiney especially the copper points.

 

The last think you want is copper open to the atmosphere. Any switch using coppper contacts always has some form of protection.

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EM boards actually come from the factory with like a grease film on them.

 

I suspect it was contact grease. They certainly were not bright and shiney especially the copper points.

 

The last think you want is copper open to the atmosphere. Any switch using copper contacts always has some form of protection.

Yep good point, but really my reply was related to plugs/connectors you buy nowadays that are plated. I have replaced pins in the past and found myself having to take off and put back on the new edge connector to make proper contact. When I was plating back in the 80's we had a contract with 'Siemens' to silver plate copper contacts. 100's of thousands. I am aware of electrical grease made for a specific purpose, but I don't see any for EM pinball leaf/wafer type contacts that move a lot. Most electrical greases are for like car batteries terminals and the like. I am speaking generally here, most EM's now are indoors, a prized possession, or a shed not exposed to the elements like at carnivals. This reply isn't intended to start a debate. In hindsight I shouldn't have posted #35 at all.

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  • 1 month later...

I'm hopeing this forum has someone good at software programming to help develop this program for the HomeBrew pinball community .

 

The idea is to use a Rpi to play video clips, audio, pictures or a mixure of them when selected using the Rpi GPio ports.

 

A couple of requirements would be the ability to select a file to play when triggered using the GPio port.

 

The trigger should be able to immediately end a current playing file and start another when selecting another GPio input combo.

 

The player would need around 30 input combos to play around that amount of different files stored on the USB thumb.

 

That is about all I can think of right now.

 

Here is a maybe suitable Rpi project that comes close to what is required.

 

https://pipresents.wordpress.com/features/

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hi, i think i understand what you want and it sounds a bit like the reverse of the python sequencer im currently using. So if i understand it correctly, you want:

 

1. a single rasp pi to receive a GPIO input (up to 30)

2. trigger off either a sound, video, jpeg file.

3. 30 possible AV files to choose from

4. rule sets for either looping, sustained trigger, shot trigger, interrupt triggers

 

is that an accurate summary?

 

the mcp23008 has 8 IO and can be chained, addressable, so 32 possible triggers is a nice number...

 

kapGo

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hi, i think i understand what you want and it sounds a bit like the reverse of the python sequencer im currently using. So if i understand it correctly, you want:

 

1. a single rasp pi to receive a GPIO input (up to 30)

2. trigger off either a sound, video, jpeg file.

3. 30 possible AV files to choose from

4. rule sets for either looping, sustained trigger, shot trigger, interrupt triggers

 

is that an accurate summary?

 

the mcp23008 has 8 IO and can be chained, addressable, so 32 possible triggers is a nice number...

 

kapGo

 

Yes sir, that sounds about it. I want to have videos with sound, pictures or sounds played back using the GPio inputs to select which file to play.

 

Some of them will include some of your Williams sound downloads by the way.:)

 

I'm not really after 30 individual trigger inputs, just a means of playing up to about 30 files.

 

The same system Williams used for sound triggering on the system 7 sound boards is actually what I am after as I will be using Williams system 7 boards, just not the sound board.

 

The idea is also a means of allowing people to upgrade there older pinball sound board right back to the chimes era and replace it with a Rpi that can not only play sounds but also video and pictures if they desire with files they can make up to play when a trigger has commanded the Rpi to play the content.

 

I already have Rpis and can take care of any hardware requirements for the system.

 

What I require is the software on an SD card I can load into the Rpi to make it all happen or the software I can upload and install on an SD card myself.

 

If you know how to write or modify the software to do this I would say you are the perfect person as you understand how the Williams sound boards are triggered already.

 

To sum up, an Rpi to replace the Williams sound board that not only does the users sound but pictures and video as well if required. Output from the Rpi video would be composite, not HDMI and sound, stereo if possible using the Rpi's AVI port that will intern go to a suitable stereo amp.

 

File types would ideally be MPeg 4, WAV, mp3 and JPeg.

 

Ideally but not necessarily if the the player can't do them. Video, audio files can be converted to the required files if need be.

 

Is this something you would be interested in working on?.

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oh right. so you use a sys 7 mpu board to generate sound triggers as per normal sys 7 pins, but instead of going to a soundboard it goes a rasp pi, where it then plays audio or video?

 

thats funny, it is the complete reverse of what i do, replace the sys 7 mpu board with rasp pi and trigger the sound boards :D

 

sure, that'd be interesting to work on.

 

as you are using the sys 7 mpu can i assume that the clock and game speed will be the same ? the sound boards run at just under 1Mhz.

what model pi are you using? i have an old model b or something but i have been thinking of getting a new one to see what i can run of it.

 

i've only looked at sys4-7 and the sound boards have 6 connections at IOJ3 but i only ever found 5 of them being active, so i assume thats still true.

 

 

also if thats what you want the sounds for then they will need to edited appropriately...

 

and when all these crazy people replace their sound boards they can give their old Williams ones to me.. ;)

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oh right. so you use a sys 7 mpu board to generate sound triggers as per normal sys 7 pins, but instead of going to a soundboard it goes a rasp pi, where it then plays audio or video?

 

Yes, that is the plan but I'm hoping the Rpi sound board can be used on earlier machines if need be.

 

 

as you are using the sys 7 mpu can i assume that the clock and game speed will be the same ? the sound boards run at just under 1Mhz.

what model pi are you using? i have an old model b or something but i have been thinking of getting a new one to see what i can run of it.

 

I don't want to alter the clock and game speed. The Rpis I have a 2bs. The Rpi 3 is virtually the same but with WiFi and BluTooth. Both these features of the Rpi 3, I don't think are needed on this project however the BluTooth could be used for BT headphones I guess. The Rpi3 has also had the sound quality on the AVI port improved over the earlier Rpis.

 

 

i've only looked at sys4-7 and the sound boards have 6 connections at IOJ3 but i only ever found 5 of them being active, so i assume thats still true.

 

That is my understanding on how the triggers work. The earlier games used solenoid drives, 5 of them and the later used 5 logic level I'm pretty sure. I'm not sure on the system 9 and later though.

 

also if thats what you want the sounds for then they will need to edited appropriately...

 

and when all these crazy people replace their sound boards they can give their old Williams ones to me.. ;)

 

I don't have any sound boards but I'm sure others that see they can use this project to replace the original sound board with one of these and that allows them to alter the sounds, add video, graphics, speech or replace the chime sounds with any of the above or simply add chime sounds that now have a volume control over the chime sounds.

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One of the interesting side effects of having a sound board that can only play one sound at a time is that (especially with the williams boards) each sound can fill the audio spectrum, it can be played uncontested at a loud volume and also theres the unique but subtle effect of foreshortening a sound that increases tension/anxiety in the listener. An example in playthrough is when theres general background noises and effects but a higher priority sound "punches" through gaining the attention of the player. This can be done through amplitude but, typically in the williams, it is done though cutting off the previous sound. So a by-product of design limitations but useful in the end.

 

Another example of that in action is in the star wars film when obi-wan is chasing jango fett through an asteroid field and fett releases charged devices (similar to a depth charge) that explode proximal to obi-wans ship. in the film the sound track goes to complete silence for a split second before they explode.

 

The later boards have those background sounds or two that still get cut off with a higher priority, incidental sound, so they were getting close to multiple, simultaneous sounds in these systems. I noticed in Johns-Arcade thread about the Sinistar cockpit game that it uses two sound boards and two pairs of speakers deriving sounds from two different roms. I have yet to dig into this to see how this all works but, im guessing, it probably doesn't include multiple sounds at once cos its still the same game logic driving the triggers.

 

You will have to forgive my ranting about williams sound boards but as far as im concerned they are the best sound generating devices since AG Bell said "come here".

 

Back to the main bit though, Autosteve does your system then still require the Pi sound boards to respond to the grounding of the IOJ pins? or is there some other way that the pi gets the GPIO signals. I also assume that you want to use the I2C bus?

 

I have just finished making a fifth controller board so i can use that as a test harness, and then depending on whether the pi needs to respond to grounding of the pins, i can make the multiplexer part out of the spare MCP2008s i have and maybe get some more gates later if they are required.

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Do it exactly as Williams did it suits me fine.

 

As for @David_AVD first question, I was thinking not to stop say Flash's background sound when another sound is required such as a scoring sound but Williams did actually stop that sound, did the score sound and then resumed the background sound.

 

Either way, I'm not really fussed because this idea is also about video. Hell, I'll use another RPi solely for sound if need be, they are so ridiculously cheap but I seem to remember reading about that Rpi project I linked to, you can have different sounds coming out of different speakers anyway and at different volumes.

 

I say @kapGo do as you think best. I have total faith in your judgement regarding this project.

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aight, well i have a pi arriving in a few days that i can dev on, and i will have to order some more AND gates cos i ran out, and build a prototyping board for it all, hook it up to the spare controller board and fire off a few triggers. That shouldn't be too difficult as essentially all im doing is flipping a IO bit in already written code and adding the usual print("Input triggered!!").

 

AV playback however will be a bit trickier. ive read a bit of the docs on OMX, openMAX etc for audio and video playback so i have a good place to start, ive also briefly looked at running threads on the pi. Plus theres a fair bit of code on github at the raspberrypi repo, but the broadcom chip itself has little in the way of documentation that i could find. But it all seems doable.

 

As for the ideas regarding the playback of audio, its all stuff that can be configured in software, or changed. Thats the good thing about running the pi for audio, there arent the same levels of limitation that the original 6802 MPU presented the programmers way back in the late 70s.

 

i will update this thread when bits arrive etc

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When I mentioned AV for the video playback I was referring to the RPi's composite output as opposed to the HDMI output.

 

This is solely because as this project is designed mainly for pinball use, only small displays would be used and these are mainly Tft displays that usually only have a composite input.

 

If the Rpi outputs the video on the HDMI port, then a converter would be required. These converters, HDMI in to composite out are usually more expensive that this project is likely to cost.

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When I mentioned AV for the video playback I was referring to the RPi's composite output as opposed to the HDMI output.

 

 

yeah that is good thing, probably less overhead for the broadcom chip. hdmi or svideo is only a software switch in the pi but i think the displays you have in mind arent going to be hd widescreens huh so composite is good.

 

but back in hardware land, the distributor that "was" sending me a pi2 has now informed there arent any left. so im getting a pi3 in a couple days instead. unfortunately the pi3 has an upgraded broadcom chip so its speed has gotten a bump up some mhz, so i will take that into account. im not sure how important it is but im going to start from the perspective of an embedded dev, even though the pi isnt really in that category.

 

so while i wait here's some ideas for the organising of the logic and not really knowing how far to future proof but i figured on maybe using a sound filetree that has Mono, Stereo and Background folders for the samples. The mono ones could be panned left or right depending on what triggers them, the stereo can be just that, and background could be constant but ducked when a high priority sound is triggered. maybe the priority system can be built in with the filetree so that mono sounds are always higher priority than stereo and background ie: mono > stereo > background. And i think the files should be numbered: 01.wav, 02.wav, 03.wav etc. This way any file replacement can be simple and restricted to filenames that are appropriate and not requiring the coding of a whole lot of string checks.

 

Multi-tap sounds are a thing though... the ones that change in pitch with every successive trigger. maybe the naming can use a sentinel os its 01-1.wav, 01-2.wav, 01-3.wav

 

You can add so many dynamics to the sounds now that its run off a pi so you should take advantage of that with panning, volume changes, etc.

 

Also ive (cos the pi aint here) yet to properly profile long term, multiple, rapid triggers to see how it handles any latency and memory use, and there may be a better option to use just pcm sound files as the broadcom chip api doesnt provide an actual audio decoder - which is nuts, not even ogg. but i will know more when i get to play around with it.

 

btw, these are just ideas

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