# Montclair's Electrocution Prop Nightmare



## Montclair (Nov 20, 2007)

This is a carryover from the Four Channel Prop Controller Using Arduino (FourBanger) thread. I decided it was better to move this off of there, instead of constantly polluting that one with this nightmare of a project of mine.


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## Montclair (Nov 20, 2007)

Moving the 12v actuator lines out of the AC braid gets me down to 50% failure rate (or at least 2 out of 4 before I started fooling with other stuff). I also added caps on the Uno 5v rails and that does nothing. I'm going to reprogram the leg actuator Uno at the problematic spot and see if I doing nothing there stops the problem.

//edit: Okay so I just found something odd while I'm reprogramming. My slave Uno is getting some power from my master Uno via the master's pin 12 to the slave's pin 11. I thought 12 was only supposed to momentarily trigger, not supply voltage the entire time. Mike or Dave or anybody know what's going on there?

The "On" LED comes on steady and the "L" LED flashes very dimly for a while then stops, much like if it had its own power, but not enough.


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## Montclair (Nov 20, 2007)

So, the master Uno started resetting even without the legs connected to the slave. I put RC snubbers on three other AC relays to cover the beacon / siren and the christmas lights, and that seemed to help. Once I reconnected the slave Uno, however, it was the same story. The master just kept resetting.

I found the wall wart to my speakers was damaged so I unplugged everything, fixed that, and plugged everything back in, and my slave Uno decided it had had enough and fried itself.

It's stuck now with the "L" LED on continually. I've tried resetting it, reprogramming it, etc., but it's non-responsive. The port shows up in Windows, but uploading to it fails.

I have two more Uno's unused but at this point, I don't even know whether I should bother with this anymore. It's such a shame as I put months of work into this thing and was so close to done. Guess it's better to have fried now than on Halloween night.

Still though, I'm discouraged as all I've been doing lately is try and accommodate the prop controller. It shouldn't be this difficult to have relays switch things on and off.

Maybe I need to invest in a professional prop controller. Thoughts?


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## Montclair (Nov 20, 2007)

After a day of research, I've tried reprogramming the broken board with a new bootloader, but I'm getting error messages, and after more research, I apparently need a 10uF capacitor to help reprogram the bootloader, and even after that, there's no guarantee the board will work.

So, I'm dumping the board and just using another one I have on hand. I'll connect everything, and the project will be what it is, failures and all. I've had enough of this thing and I think everyone is out of ideas on how to fix it.

If you've got some, please do share.


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## Matt Roberts (Jul 15, 2016)

Just as a test if you move the acuators onto the main board and disconnect the slave, do you still get resets?


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## Matt Roberts (Jul 15, 2016)

You could try these from radio shack across the relay contacts for the 12v stuff.
https://www.radioshack.com/search?q=Mov

Also have you tried removing the gnd wire between the two arduino and just using the gnd from the two barrel jacks .


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## Montclair (Nov 20, 2007)

*SUCCESS!* I swapped out the dead slave Uno for a new one, and put the master's relays on it's own 5v power supply. No more resets.


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## BillyVanpire (Apr 22, 2015)

congrats Montclair!

great prop you made there


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## David_AVD (Nov 9, 2012)

It's ALIVE !


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## RoxyBlue (Oct 6, 2008)

Congratulations, Montclair! Your persistence has paid off. Or maybe making your own thread broke the spell that bound the electronics:jol:


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## Montclair (Nov 20, 2007)

Matt Roberts said:


> You could try these from radio shack across the relay contacts for the 12v stuff.
> https://www.radioshack.com/search?q=Mov
> 
> Also have you tried removing the gnd wire between the two arduino and just using the gnd from the two barrel jacks .


I drove 40 minutes to Radio Shack on Saturday and looked in all the bins. They didn't have the movs. I could have bought other components for the 5v rails on the boards, but completely forgot.

I have not disconnected the ground between the two Arduinos. What would be the benefit of running both of them to the barrel jack? Is that what they call a ground plane?


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## Montclair (Nov 20, 2007)

Thank you, guys, for the congrats. It's really owed to all the help I get here on the forums. The laws of electricity are not something I know very well or many of, so this is the place I come. Dave, Mike, and Matt have been so helpful, knowledgeable, and nice. Thanks to you guys, and everyone who pitched in with suggestions. I really appreciate it, and now I know how to make these things work! Yay!


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## Matt Roberts (Jul 15, 2016)

GREAT STUFF, really glad that it works, was worried you was going to scrap it. Its a great prop!


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## Matt Roberts (Jul 15, 2016)

Montclair said:


> I drove 40 minutes to Radio Shack on Saturday and looked in all the bins. They didn't have the movs. I could have bought other components for the 5v rails on the boards, but completely forgot.
> 
> I have not disconnected the ground between the two Arduinos. What would be the benefit of running both of them to the barrel jack? Is that what they call a ground plane?


I read online whilst trying to solve my own reset issues that it can help if all the gnd wires come back to one point so that there is only ever one ground connection between all the modules.


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## iowachap (Aug 19, 2015)

Awesome!


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## FistJr (Nov 11, 2014)

Very nice! Congrats on your persistence in working through the issues. That last 5% is always what takes the most time....

I had a similar electrocution prisoner setup. I added a smoke machine with the output tube hidden up the back of the prison's shirt, with the output right by the prisoner's head. It made his whole head smoke from the "electrocution", and added a very nasty effect. Even when the electrocution and the smoke machine stopped, residual smoke kept drifting out slowly, making it look like the prisoner's "sizzling" was not quite done yet...


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## Montclair (Nov 20, 2007)

Matt Roberts said:


> I read online whilst trying to solve my own reset issues that it can help if all the gnd wires come back to one point so that there is only ever one ground connection between all the modules.


Hmm, okay. Well if this thing gives me any more problems, that will be next. Thanks!



FistJr said:


> Congrats on your persistence in working through the issues.


Thanks! And. yeah, I have been considering adding a fog machine to it. At this point, I just want to finish. I'll be adding a couple more cool things to the chair to light it up (if my plan works), too!

Anyway, here's the latest vlog entry on this, back when I started having problems this past weekend. Enjoy!


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## Montclair (Nov 20, 2007)

Made a lot of progress in this vlog episode. I expect one more episode on this sucker, and he'll finally be done. I cover the Arduino reset issues in this episode, and all of the things I've learned about counteracting them, including diodes, RC snubbers, mov varistors, and separate relay power supplies. Enjoy!


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## Montclair (Nov 20, 2007)

I wired up the light sticks like this. They work fine. I'm wondering if anybody sees a problem with this.


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## David_AVD (Nov 9, 2012)

You may have issues if the relay for the mode change is ever activated when the relay for the stick power is not on.

A safer way would be to not jumper the negative between the relays and instead run the mode relay contacts to the stick separately.


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## Montclair (Nov 20, 2007)

There's no relay for the stick power, Dave. It's always supplied. The relay is acting as a switch to tell the little chip on the stick that there's a connection on those pins. Once the relay is closed, the stick fires up. The relay can then open right back up and the stick continues to light.


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## David_AVD (Nov 9, 2012)

ahh... you're correct. That will teach me to reply while watching TV !


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## Montclair (Nov 20, 2007)

Heh! Well, does this mean I have your seal of approval? 

Man, I really botched the relay wiring on my first attempt. It's what fried my slave Arduino and 5v power supply. I accidentally ran 12v through these relays! After I figured out my mistake, I then proceeded to incorrectly run 5v through them. D'oh!

I figured out that I didn't need 5v from the supply through the relays while I was drawing the picture to post here and ask for help! LOL! So, I went back downstairs, removed the 5v supply through the relays, and the stuff worked right. <sigh>


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## David_AVD (Nov 9, 2012)

Sounds like you have it working well now.

While I may have shouted at the screen more than once watching the videos, I'm impressed that you stuck with it and came up with such a great prop.


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## Montclair (Nov 20, 2007)

Heh! I can just imagine. It's difficult for an expert to watch a novice. I have the same problem when I read other people's computer programming. I do appreciate the help, greatly!


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## Montclair (Nov 20, 2007)

Here's a carryover from the $20 prop controller thread where we discussed grounding and separate power supplies for the Arduino and relays.


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## Montclair (Nov 20, 2007)

*Arduino Electric Chair Prop - DIY Halloween Vlog 2016 #48: Electrifying! (Part 16)*


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## Montclair (Nov 20, 2007)

*Weekend Update*

Weekend Update:

Short version: Burn stuff up, replace it. New idea, wire it in but some faulty insulation causes a hidden short circuit, so spend the rest of the day trying to fix it. #poopysunday

---
Long version:

It's been a frustrating build, for sure. Three months on this thing that should have taken a week. When I think I'm done, I either add something else, I burn something up, or the controller starts failing. Today, I spent almost every waking minute working on the electrocution prop.

I came up with an idea to have my LED light sticks running in their "standby" mode while the prop is waiting for somebody to trigger it. It will look so awesome this way, that I must do it! After programming that into the controllers, doing a lot of rewiring, and being ever so careful by testing voltages and grounds and whatnot, I then proceeded to plug the 5v LED sticks into the 12v jumping leg connectors. Ya got that? Here it is again. I connected my 5 VOLT LEDS to my 12 VOLT connections. Unreal.

Not knowing I'd done this, but seeing as how they weren't responding correctly, I unplugged, checked voltages, reviewed wiring, and replugged, and the sticks fried. Ungh!!!!!

After desoldering them, and soldering in new ones, as well as some other rewiring to clean up a little and add another 5v power converter to the 12v system, I checked all my connections, plugged things in correctly, and... the LED sticks didn't work correctly! Oh what the heck?! Seriously?!

I then spent 2+ hours trying to understand why they weren't doing what they were supposed to do. They'd just turn on and never shut off. It made no sense.

Eventually, I found that I'd created a hidden short circuit, thanks to some shrink tape that was just a hair too short, and it was grounding out, shorting out my LED light stick connectors. So I pulled all of that work apart, redid the wires, and the stuff works correctly now -- almost. My idea is sound, but the programming is a little off.

Anyway, a very, very frustrating day. I wanted to finish the prop, and the net result of all the work was minimal, to say the least.

At this rate, I'll be burnt out before the guy in the chair is.


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## David_AVD (Nov 9, 2012)

To help avoid mishaps like that, I often use those cable ties with the write-on flap to mark the voltage or channel number. They go on the wire as close as possible to the connector so I'm more likely to see it and think before plugging in.


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## Montclair (Nov 20, 2007)

I had already lettered all the connections. I just wasn't paying attention -- or maybe I'm just like these guys:


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## Montclair (Nov 20, 2007)

*It's done!*

The final vlog episode on my homemade Halloween electrocution prop. It's done!


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## Montclair (Nov 20, 2007)

Since my vlogs may be too long for folks to watch, here's a quicky of my completed Arduino based Halloween electric chair / electrocution prop.


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## fwghost (Sep 30, 2013)

Nice job, definitely seems worth all the trouble it gave you!


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## Montclair (Nov 20, 2007)

Thanks!


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## fogkeebler (Oct 2, 2015)

Excellent work. I have been following your progress and have been watching your tube channel. definitely raised the bar!!


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## Montclair (Nov 20, 2007)

Thanks, foggy!


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