# Converting MitB from Motor to Pneumatics



## Zombie-F (Apr 12, 2004)

I'm considering converting my MitB to a pneumatic one driven by a prop-1 this year. I already have a compressor, I just have to learn a little more about pneumatics (and scare up the $$ for the stuff) before I dive into this.


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## gmacted (Jan 18, 2006)

Zombie-F,

How are you going to change your MitB? I am also planning on building a MitB this year. I plan on using a PIR detector to trigger it. I'm not sure if I want to use a Prop-1 controller or custom design the electronics to control it.
This is my plan right now. I will have a spot light on the box and when the Tot'ers get close enough (a PIR will detect this), the spot light will turn off, the light inside the box will light, the fog machine will burst on (I will need to modify the controller), a monster sound (ump3 player or parallax AP-8 audio player) will play, and the lid will open (using the Zombie-F design). When the lid shuts (limit switch on the lid), the entire system will reset itself waiting for the next TOT'er.


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## Zombie-F (Apr 12, 2004)

Ooh. A limit switch would definitely work! I'd pondered that idea long ago and just kind of forgot about it.

Essentially, I want a PIR to detect the presence of a TOT, turn the light on and fill it with fog before the lid starts to lift. At this point the growling starts via an AP-8 and some amplified speakers.

Then, I either want to pneumatically have the lid slam open and closed randomly a bunch of times OR just have it open and close like 2 - 3 times and stop with the current motor/cam version. I could set the prop-1 to detect the closing of a limit switch and when it reaches 2, have it shut it all off and wait 30 seconds before it could be triggered again.

Maybe I'll upgrade to pneumatics in the future and just upgrade the electronics this year. Currently, the prop is just "on" all the time. I think it would be more effective if it were triggered on a "per-user" basis. 

Thanks for jogging my memory.


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## gmacted (Jan 18, 2006)

Zombie-F,

It sounds like we're trying to do the same thing, except I never considered having the lid open and close several times. the circuitry to achive this probably won't be too bad and I don't know if I want to spend the money on a prop-1 controller. Do you have any experience with the AP-8 sound player? I'd like to know what the sound quality is like.
I know you would like to use pneumatics, but wouldn't a higher RPM motor do the same thing?


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## Zombie-F (Apr 12, 2004)

gmacted said:


> I know you would like to use pneumatics, but wouldn't a higher RPM motor do the same thing?


Possibly, but I think a motor that can lift the heavy lid AND can spin at a faster rate would be VERY expensive. I tried many motors before I found the one that could get the job done and if I'd had to buy it, it would have run me $80. I'm sure if you dig around the net long enough, you could find something reasonably priced that can get the job done.

I imagine the AP-8 probably has sound quality on par with the ISD Chipcorders, which is good enough for this prop. I use a chipcorder currently and it does just fine in this application.

As for the switch, a prop-1 can be set up to count how many times the switch closes and be set to stop once that counter reaches a certain number. I actually think the prop-1 would be perfect for this type of prop. If only it'd been around when I first built this sucker.


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## gmacted (Jan 18, 2006)

Zombie-F,

Just had another thought. How about a slight modification to your cam. You could modify it to lift and lower the lid (to different levels) a few times as it spins around. This would give it a more random effect. I'm not sure if I'm explaining it very well.


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## Zombie-F (Apr 12, 2004)

gmacted said:


> Zombie-F,
> 
> Just had another thought. How about a slight modification to your cam. You could modify it to lift and lower the lid (to different levels) a few times as it spins around. This would give it a more random effect. I'm not sure if I'm explaining it very well.


I know exactly what you mean. I'll also look into this if I approach re-vamping this prop this year.

On a side note, I'll be splitting this discussion off from the existing thread as it's gone pretty far off-topic.


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## gmacted (Jan 18, 2006)

Sorry. I guess I just got carried away.


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## Zombie-F (Apr 12, 2004)

gmacted said:


> Sorry. I guess I just got carried away.


No need to apologize... a good topic sprung forth from this. It happens from time to time, so no need to be sorry.


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## Zombie-F (Apr 12, 2004)

madmax said:


> Two words......Wiper Motor
> 
> Ok, I have more than two words to say  The wiper motor is cheap, strong and can lift your lid and close it many times in a few sceonds. And if you really wanted to save some money. Use your sound chip on another prop and switch this prop to a loop cassette. You'll probably get better sound from the cassette.
> 
> ...


I have always had some doubts as to whether or not a wiper motor could lift this lid. If I remember correctly (and I seldom do), the lid weighed in about 12 lbs at the point of contact for the lifting mechanism. I obtained this weight by placing a scale inside the box and propping a rod between the scale and the lid's lifting point.

I guess the only/best way to find out if a wiper motor can do it is to take the dive and just try one out.  They are cheap enough that I could experiment with this.


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## Dr Morbius (Sep 21, 2004)

My god, MadMax, my hero, has given yet another kickass idea! My kicking hangman runs on a wiper motor, and has a fluid kicking motion, which I really dont like...Now I will put a blinker fuse on it, which would make it kick more randomly! Thanks Max!


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