Q*Bert- SirP, 1UP, check this out...

[_Iz-]

Another Q-Bert knocker project, apparently mostly functional. Quite a clever approach.

http://members.cox.net/brado426/QMAME.htm

thread on mame.net where I found out...

http://www.mame.net/cgi-bin/wwwthreads/showpost.pl?Board=mamegeneral&Number=124489&page=0&view=expanded&mode=flat&sb=7#Post124489


Edit by SirP:  Modified the title.  1UP needs to see this too

[Dartful Dodger]

That's good news, I like real knockers.

[SirPoonga]

Yeah, nice idea for a dedicated q*bert mame.  However, not the solution I want.  It hooks up to the keyboard LEDs.  Bad bad bad.  I use the LEDs.  I've got to look at my PMs I think transfer of parts went from Kelsey (oscarcontrols) to 1UP.  I was working with Kelsey on a parallel port I/O device that not only a knocker could be hooked up, but force feedback motors, more LEDs, etc..  Ahh yes, Kelsey was suppose offload the project to 1UP as 1UP really wants force feedback on his t2 guns.
Last I heard form 1UP is we are looking into a USB solution right now.

You know what the problem with an actual pinball knocker, it;s an odd voltage.  Like 27V or something like that.  How am I going ot get power to that from inside the cabinet.


1UP, did you order that USB I/O card yet?

[1UP]

1UP, did you order that USB I/O card yet?

Ummm...no...  

Sorry, it's gotta wait another week or two, I just got a bunch of books and DVDs, and I've gotta pay off my new Dell Axim before I start any new projects...but it's definitley going to happen!  

[SirPoonga]

Hehe, just giving you a hard time man!

I think our solution is better for the BYOAC community anyway.  Many people use the keyboard LEDs to light up buttons and such.

[menace]

I don't know if this is relavant or not but I just bought a q-bert with a working knocker so if anyone wants pics or part no., I would be happy to lend a hand--It sounds like you have the knockers well in hand though

[SirPoonga]

The knocker is just a pinball knocker, nothing out of the ordinary.

1UP, I have to look at the source code, that dude's site says knocker support broken in .74.

[RandyT]

The knocker is just a pinball knocker, nothing out of the ordinary.

And if I'm not mistaken, a pinball knocker is just a solenoid, positioned to bash the side of the cabinet when activated.

I'd guess you could use just about any 12v solenoid as long as you could mount it properly.  It'd be easier to supply that voltage than 27v.

RandyT

[SirPoonga]

True, I think Kelsey tried a 12v or a 5v solenoid.  Just doesn't make as loud of a thump.

[OSCAR]

The solenoid wouldn't even actuate with 12VDC.  Of course since I sent everything to 1UP, I now have a Mad Planets (Gottlieb) cabinet that has a +30VDC source that Gottlieb uses for the sound board amp & knocker on Q*Bert.  The Gottlieb power supply rectifies the +30VDC from a 35VAC tap off the transformer, so you would need both a Gottlieb transformer and power supply to get the +30VDC to power the solenoid.

Here's a pic of the power supply (upper right board):




...and the 20lb monster transformer:




A Williams power supply has a +27VDC source that may work (and easier to find than Gottlieb arcade power supplies), but again the +27VDC is rectified from a 20VAC tap from the transformer.

It may be just easier to find a pinball power supply & transformer to drive the coil??  I don't know the lowest voltage that will actuate the coil, but it definitely wouldn't work off of 12VDC.


##EDIT##

Just to clarify, what I tried was a real Gottlieb knocker powered by a lower voltage.  Here's a pic of the Q*Bert knocker:




The lower voltage solenoids I tried didn't have much "knock" to them at all.  I would say more like a mild tap.  

I would imagine if you went through the trouble to wire up a knocker and ended up with a pitiful little tap, you would be quite disappointed with the results.  I would say that powering a real knocker will get you what you really want, rather than taking the easy way and actuating a smaller solenoid.

[Xiaou2]

 I noticed once that HP printers use 30volt power supplies:

http://web1.applelaptopbattery.com/ccp5/cgi-bin/cp-app.cgi?rrc=N&pg=prod&ref=C8442-60026

 Would this work?

 How many amps does it need to make the selenoid slam hard?   Is that what the higher amps do? (give more powerfull burst?)

 

[RandyT]

The amount of power a solenoid has is based on the number of turns of wire that comprises the electromagnet and the amount of current, not the voltage.

A 12v solenoid doesn't necessarily indicate a "weaker" actuation.  It'll take more current at 12v to get the same amount of force as 27v though.  For example, the starter in your car has a very powerful solenoid in it, and it runs from 12v.

It's not surprising that a 27v solenoid won't do anything when fed 12v.  You just need to find the right 12v solenoid for the application and be able to feed it enough current to actuate it properly.

(where's Grafixmonkey on this one? )

RandyT

[SirPoonga]

Would the car solenoid work then?  You can pick those up at junk yards then.

[OSCAR]

Ya know, Randy, that is a pretty good idea.  I'm almost embarrassed I didn't think of that since my family has been in the auto parts business for 60+ yrs!  I'm the black sheep who (*gasp*) didn't decide to go into the family business, and instead become one of the effing engineers that is the root cause for most of their troubles!  At every holiday, I have to try to convice my dad and uncles that there really isn't some kind of engineering conspiracy that there is always one bolt located on a water pump that you just can't quite get to...  

Anyway...  I bet an automotive solenoid would be suitable, assuming that the draw on them wouldn't exceed the limits on the 12V line of a PC power supply.  In any case, I would put the solenoid on a different power supply than the one connected to the motherboard.  Solenoids cause a large spike when actuated that could potentially harm a motherboard unless it was properly protected by diodes and/or optoisolators.

[SirPoonga]

Yeah, I'd put that on a seperate power supply too.  PC power supplies are cheap, and so are arcade power supplies.  Both give you a 12v line.

[kspiff]

That's good news, I like real knockers.

Doesn't everyone?

[RandyT]

...I have to try to convice my dad and uncles that there really isn't some kind of engineering conspiracy that there is always one bolt located on a water pump that you just can't quite get to...  

I'm an engineer too, and there is a conspiracy.  Didn't you get the memo?  

But seriously, after working with engineers for a while, I've found that they tend to have pretty narrow focus.  Every once in a while, I have to threaten that they will be the ones assembling the first 100 units of what they design.  It's amazing how much more thought goes into the process after that .

RandyT

[pathdoc2]

I didn't have a chance to play much Q-bert as a kid but I enjoy playing in now on a Mame machine.  For the life of me I can't figure out what a knocker is in relation to this game.  What have I forgotten or overlooking?  

[clok]

When you hop Q-Bert off the cubes and he falls to his death (I assume, maybe he falls, and is just severly injured) you get a nice Knock on the bottom of the cab to simulate his hitting bottom. Just a nice little touch to make the game more interesting.

Clok

[Wienerdog]

I have some of these solenoids that work decent at 12v straight from the computer power supply.  I got 5 of them for another project, pretty nice for the cheap price.  Have you guys tried pull solenoids like this with a spring or have you been using the push solenoid to strike the knocker?  

[Xiaou2]

Wienerdog, those look nice for a project Id like to start.  How much distance do they travel when on from the off position?

 

[Wienerdog]

I give it about 5/8" of pull.  The rod has about 7/8" of throw from full rest (the spring pushing the rod all the wayout).  You need to push the rod in about 1/8" to 1/4" before applying the 12v dc or the rod won't engage.

[1UP]

I have some of these solenoids that work decent at 12v straight from the computer power supply.  I got 5 of them for another project, pretty nice for the cheap price.  Have you guys tried pull solenoids like this with a spring or have you been using the push solenoid to strike the knocker?  

I bet a nice 24v unrectified adapter from Radio Shack would make those kick nicely...

[spidermonkey]

A little rediculous but you could plug in a microphone into the computer and mount it next to that anemic 12v solenoid to make it a little more audible. Just a thought.

[Wienerdog]

Anemic?  You guys are gonna love this.  I live in a two-story house with a basement, I was messing around with this in the basement last night.  My wife asked me this morning if I was playing pinball at 11:00 last night.  She said she woke up to this "clunk, clunk, clunk" sound and didn't know what I was doing.  

I was firing the solenoid into the side of my metal computer case trying to measure the longest throw I could have while still ensuring the rod would be pushed in far enough to engage every time.  I probably "clunked" about 20-30 times.  It's a good thing that she thought it was only 11:00.  Of course I told her "no honey, maybe it was the water pipes ."   I've learned that "sorry honey, that was my future QBert knocker" isn't always the best answer.