# PicoBoo / PIR trigger circuit



## Otaku (Dec 3, 2004)

Some members have asked about how to trigger a PicoBoo controller using a 5VDC PIR sensor. The PicoBoo needs to have it's V+ trigger output shorted to the Trigger In terminal to start the routine but the average PIR can't do that. I contacted Fright Ideas and they sent me the circuit drawing that addresses this. I built out the circuit and it works great. The circuit supplies the 5VDC needed for powering the PIR, and shorts the V+ voltage to the Trigger terminal on the Pico when the PIR goes high. No external power is needed as the Pico supplies the 9 - 12VDC power. Note that your PIR must be the kind that goes high when it sees a heat source. Most sensors work this way by default, others have a jumper that switches the output between high and low. Here's a link to the circuit drawing from Fright Ideas.

http://www.hauntforum.com/picture.php?albumid=919&pictureid=13280

The version I built is for the controller without the "C" terminal. I'll post pics of the board and a parts list in a couple of days.


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## niblique71 (Dec 2, 2009)

Now that is Just TOO COOL, and it looks simple enough. With my current skills I wouldn't have figured that out. Brilliantly simple.

THank You!


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## Otaku (Dec 3, 2004)

Here's the parts list. All parts are from AE, except for the perf board from RS. The total cost of the board is $2.81, w/o shipping.

3-postion T-block, 2 ea.
TER-503 .40 ea

NPN transistor, 1 ea.
PN2222N 5/.80

5VDC regulator, 1 ea.
78M05 .50

1K 1/4W resistor, 1 ea.
Order as shown 10/.50

Disc capacitor, 0.1uF, 2 ea.
104D50 10/1.00

Dual-mini board, Radio Shack
276-148 2.19

Hook-up wire, 26 - 30 ga.
As needed.

I suggest using a 3-conductor servo cable like this one to connect the PIR to the board. Just cut off the male connector and strip the wires for the T-block.

http://www.allelectronics.com/make-...RVO-EXTENSION-CABLE-FUTABA-HI-TEC/JR-S/1.html

Links to the pics:
http://www.hauntforum.com/album.php?albumid=1108

One other thing - I find there's ~270mV across V+ (9VDC) and the Pico's trigger input when the board is idle (no PIR signal). I'll check with Fright Ideas to see if this is an issue.

Edit - nope, the 270mV is no problem. I forgot to include an LED that lights when the PIR sees a victim, I can add that if anyone thinks its necessary.


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## goo eye (Jun 18, 2012)

Hey Otaku. I would like to build this circuit, but you link to the circuit diagram no longer works for some reason. Can you repost it or send it to me via email please? Thanks.


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## goo eye (Jun 18, 2012)

Oh no, sorry, it is working now. Do you know what the 1k resistor is there for?


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## Otaku (Dec 3, 2004)

Hi goo eye,
The 1K resistor is for limiting the current to the base pin of the transistor. Helps prevent damage.


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## niblique71 (Dec 2, 2009)

I haven't built the circuit yes but I WILL for this Halloween. Thanks again Gary.


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## niblique71 (Dec 2, 2009)

Wow!! I finally built this Circuit and WOW!!! It works Fantastic!!! Thank you SOOO MUCH Gary.

I Discoverd PIR's and how much more reliable they are for Good triggers when I bought an EFX TEK Prop Timer. Easy to aim and control for perfectly timed and very reliable scares. I bought the parts from radio shack for about $17, but Purchased online I'd bet you can get everything for under $10

Thanks again. I'm going to build several of these


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## ruafraid (Jan 3, 2006)

Does a schematic exist for this ? Not sure I can follow the pics for connections


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## niblique71 (Dec 2, 2009)

ruafraid said:


> Does a schematic exist for this ? Not sure I can follow the pics for connections


Did you already see This Diagram?

Gary, I noticed you used capacitors in your version. Fright Ideas doesn't have them in thier schematic. What are the caps for and what advantage do they add to the circuit. Noise reduction?? My circuit worked flawlessly through out the evening last night without the capacitors.

Thanks again. I love this Trigger.

It's so easy to add a piece of tubing to direct or constrict the trigger zone using these PIR's. SOOO Much better than a hacked motion detector.


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## pshort (May 6, 2008)

The caps are on the input and output of the regulator, and are highly recommended by the manufacturers of the regulator for stability (keeps them from oscillating) and for transient response.

I would recommend that you use them, even if things seem to work fine without them. Without them, it is possible that small changes (temperature, increasing/decreasing the length of the cables, etc) may cause problems.


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## Otaku (Dec 3, 2004)

Greg, I used two 0.1 uF decoupling caps to reduce possible oscillation in the LM7805 regulator. The caps are cheap and there's plenty of room on the board for them.

Jim, there's pics of the assembled board in an earlier post, but I haven't done a circuit layout drawing. If you need one, let me know and I'll try to get it posted on Monday.

Edit: What pshort said.


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## niblique71 (Dec 2, 2009)

Otaku said:


> Greg, I used two 0.1 uF decoupling caps to reduce possible oscillation in the LM7805 regulator. The caps are cheap and there's plenty of room on the board for them.
> 
> Jim, there's pics of the assembled board in an earlier post, but I haven't done a circuit layout drawing. If you need one, let me know and I'll try to get it posted on Monday.
> 
> Edit: What pshort said.


A schematic would help so We can locate the position of the Caps.

Also There were 2 transistors listed that would work. I bought both versions BUT the PN2222N (Spec) is listed as a PN2222A on the packaging that I bought from Radio Shack. Is that a different Transistor?? Does the suffix "A" make a difference rather than the suffix "N" ?? Will these still work?

Electronic Idiot here... But Learning...


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## Otaku (Dec 3, 2004)

Cool, I'll work up a schematic on Monday. AFAIK, the transistor should work, its just being used as a switch.


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## Otaku (Dec 3, 2004)

Here's a graphic of the trigger circuit layout:

http://www.hauntforum.com/picture.php?albumid=1108&pictureid=15417

If anyone has a question, just holler.


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## Jack Is Back (Jun 21, 2011)

I really need to check out HauntForum technical threads more often. This is so much simpler than my circuit that I've been building for my Picoboo controllers. I was using a relay driven by the 2N2222 to close on detection to trigger the controller but I won't be building those any more.

Thanks!


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## frightmare (Feb 9, 2007)

Is the problem with the cheap eBay 5v+ motion sensors the amount of juice it's getting from the pico?

I purchased 10 5v+ PIR's from eBay last year but ran into the same problem where once hooked up it just kept triggering over and over... This circuit fixes that problem but I'm not a wizard at electrical work... Especially building circuits. I was wondering if you would hook a cheap dc-dc buck converter step down module on the + and - to drop it down to the needed 5ish volts that would work?

Or is it something more complicated and needed this special circuit built?


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## Otaku (Dec 3, 2004)

If the PIR is one that can handle 9-12VDC (the Pico's output voltage range) then I'd say that the regulator could be eliminated from the circuit. But with a 5VDC PIR you'll need to have it in there. I think there's more to it than just regulating the voltage, though - the transistor is acting as the switch that shuts off the PIR's output signal, preventing re-triggering.


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## frightmare (Feb 9, 2007)

Ok, so I'm going to need to build this or some type of circuit. Crap. Figures it wouldn't be as easy as buying a $1.75 step down circuit. Granted this circuit seems to cheap to build just another something I need time for.

And yeah the PIR I have is the 5v+ one so I will need everything.


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## frightmare (Feb 9, 2007)

I put my order in today for the parts. Going with the parts mentioned in the OG frightideas image. 

Hopefully I remember to reply back here with my outcome and some pics of everything once its done. 

I have my fingers crossed that everything works.


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## hpropman (Jul 27, 2008)

Clever idea to use the transistor to close the trigger contacts on the controller. Also to add to the cap discussion I place caps on all my boards just think of them as noise filters and the power fluctuations as background noise (best analogy I can think of) sometimes with electronic circuits especially with home grown boards sometimes noise will get introduced into the circuit and the caps compensate for this. The cap is basically like a tiny rechargeable battery when the circuit is powered on the caps charge up (usually in milliseconds) now when the the power dips for example, the cap will release some of its charge to keep that voltage stable. and when the voltage returns to normal the cap regains its lost charge. caps are especially important for microcontrollers it keeps them from doing strange things. I hope this helps


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## JeffHaas (Sep 7, 2010)

I've got a question on this...

I recently got some old Haunt Master controllers and have been passing them onto other local haunters. They have a pair of terminals that when closed trigger the controller. To test the controller, you can just short the terminals with a piece of wire. Unlike the Picoboo, the Haunt Master controller does not provide any power that the PIR can use.

Is there a variation of the circuit that would work? I think I might put something simple together for the non-electronically inclined.


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## Otaku (Dec 3, 2004)

Should be do-able. Just use the transistor to short the terminals. You would need to provide power, like regulated 5VDC or a 9 volt battery, to the board to power the PIR, of course. Once the controller starts it's timed sequence it should lock out incoming triggers until it's finished.
Which HM controllers are you talking about? I seem to remember that all of them ran on and switched 110VAC to control a prop. There was one that had a PIR triggering option, but needed to have an external 9VDC source to power the PIR.


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## JeffHaas (Sep 7, 2010)

I got a Flex ECT and a RCT. You're right, both needed externally-powered PIRs to work.

They're metal boxes that you plug into the wall, and then plug another prop into. Set a couple of knobs and connect your trigger. Very simple with limited options but can work OK, which is why I'm passing them on.


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## MBrennan (Sep 22, 2008)

I'm new to pica boo and pir s, but I want to try this.

Is there a specific PIR you use or recommend? And do you also get them from AE?

Thanks.


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## Otaku (Dec 3, 2004)

Yes, you can use the PIR that's sold on AE:
http://www.allelectronics.com/make-a-store/item/PX-28027/PIR-SENSOR-BY-PARALLAX/1.html
or any other that uses 5VDC to 12VDC. There are other sources for low-cost PIRs, like around $5 each, but I can't remember where I saw them. For making extension cables for the PIRs, I use servo extension cables, the connectors match up nicely. You can usually find the length you need at hobby stores, or make your own from bulk cable.


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## JeffHaas (Sep 7, 2010)

OK, I'm a bit stumped as to how to use the schematic with the Hauntmaster controllers...I've got it breadboarded up with a powersupply and I'm testing it using a multimeter to see if the circuit closes. There's no beep from the multitester; I'm connecting to the Collector of the 2n222 and the ground.

??


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## Otaku (Dec 3, 2004)

Jeff, do you have a link to the schematic? I can't find the old Haunt Master site anywhere.


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## fritz42_male (May 5, 2009)

There's a copy of the site on the wayback machine - might be worth a look


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## JeffHaas (Sep 7, 2010)

I went to the Wayback Machine and grabbed a PDF of the info, it's attached. To get around the size limitations of the forum I've chopped the PDF up into smaller segments.


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## Otaku (Dec 3, 2004)

Okay, so it looks like the trigger input is fired simply by shorting the two trigger terminals. A PIR/transistor should be able to do this, as long as it's a dry trigger. If the transistor needs to be sinking any current in order to operate, then there would be an issue. It appears that this controller was meant to be triggered with a normally open pushbutton switch or a mat switch. I have a variation on the PIR board that operates a relay, providing a dry trigger. That may be what's needed here. I may have a circuit layout drawing somewhere; let me do some digging.

Edit: Here is the PIR/transistor trigger circuit that I designed for use with dry-trigger USB audio boards. This may work for the Flex-ECT's as well. Since the Flex-ECT has an off-interval timer, the PIR is locked out and can't re-trigger the controller until both timers run out.


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## Otaku (Dec 3, 2004)

Jeff, did you connect any power to the Flex-ECT trigger terminals? Hopefully not, the instructions state that this may kill the controller. If you did do this inadvertantly it may be the reason you can't get it to work.


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## JeffHaas (Sep 7, 2010)

Nope, I didn't short it out. I can still trigger the controller with a wire, I just couldn't figure out the extra circuit. Thanks, I'll give it a try.


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## Otaku (Dec 3, 2004)

BTW, you can use a 2N2222 with this circuit, you don't really need a Darlington; I just happened to have a pile of them on my bench at the time. Also, I didn't use decoupling caps in this circuit - you may want to add them.


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## niblique71 (Dec 2, 2009)

Now if we could Only build in a 15 second delay before a retrigger LOL. Otherwise it's still working like a charm


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## Otaku (Dec 3, 2004)

niblique71 said:


> Now if we could Only build in a 15 second delay before a retrigger LOL. Otherwise it's still working like a charm


Does the PicoBoo not have a way to lock out the PIR for a period of time after it triggers the controller?
A lockout circuit *could* be added to the existing circuit, a simple cap discharge timer would be fairly easy to put in there. I think the trick is telling it when to start timing - it would need to see a voltage signal (after the Pico is triggered) to charge up the cap.


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