Halloween Forum banner

1 - 20 of 64 Posts

·
Registered
Joined
·
126 Posts
Discussion Starter #1

·
Registered
Joined
·
3,734 Posts
There is/was. I removed it. It's sound activated. Maybe I can find another cheap prop that motion activated and steal the PIR sensor.
"Cheap" props don't use PIR's, they use photo cells that just detect a change in light intensity.
 

·
Registered
Joined
·
57 Posts
It can be done...but it depends on a few things. At the most basic level, a sensor essentially changes the flow of electricity to a specific control mechanism, which results in the control mechanism behaving a certain way. Trouble is, how the sensor does that determines how the controller behaves. For example, a moisture sensor is a specialized resistor--when resistence is changed due to water on the contacts, the signal from the sensor goes "low" and the microcontroller receiving that signal does whatever its program says to do when a "low" signal is received.


Maybe you can see the problem--if the control mechanism needs a "low" signal to do something, and your new sensor outputs a "high" signal, the control mechanism won't activate. Since not all sensors work the same, they're not necessarily interchangeable without some hacking.
 

·
Registered
Joined
·
256 Posts
There is/was. I removed it. It's sound activated. Maybe I can find another cheap prop that motion activated and steal the PIR sensor.
If it has the "try me" connection / wiring still there you can use that. You don't need the actual button.

You'd use a PIR to close the connection (possibly via a relay) where the "try me" use to go.
 

·
Registered
Joined
·
126 Posts
Discussion Starter #7
There is/was. I removed it. It's sound activated. Maybe I can find another cheap prop that motion activated and steal the PIR sensor.
If it has the "try me" connection / wiring still there you can use that. You don't need the actual button.

You'd use a PIR to close the connection (possibly via a relay) where the "try me" use to go.
Ah! Gotcha! So simply wiring the PIR to the Try Me wiring and also to power would allow it to open and close the circuit as detected (in theory). That's a great suggestion. Thanks! I'll play around with that some.
 

·
Registered
Joined
·
57 Posts
You'd use a PIR to close the connection (possibly via a relay) where the "try me" use to go.
Occam's Razor at work. That's a good $3 solution.

The one caveat that I can see may be this: it appears the prop runs on less than 5v (only 3 AAA batteries according to the description). I haven't looked everywhere, but most PIR/relay combos I've seen use 5v, and from what I've read they get wonky at 4.5v. I'd say pull out the multimeter and check the voltage running though the "try me" wires before ordering stuff, but I dont knnow what resources the OP has.
 

·
Registered
Joined
·
126 Posts
Discussion Starter #9
I can handle that. A quick and dirty search shows me I need to be looking for a setup like this. I don't care about the current voltage it is pulling from...just the output. If I get the correct PIR and relay, I can output the required 4.5VDC to power it.
 

Attachments

·
Registered
Joined
·
3,734 Posts
If it has the "try me" connection / wiring still there you can use that. You don't need the actual button.

You'd use a PIR to close the connection (possibly via a relay) where the "try me" use to go.
Unfortunately it's not that simple. A Pir continually goes off whenever it detects motion, so it will continually set off the "try me" connection. Pressing the "try me" button starts the sound track, pressing it again while the audio is playing stops it. Pressing it again restarts it, you see the dilemma here.
 

·
Registered
Joined
·
57 Posts
Ah! Gotcha! So simply wiring the PIR to the Try Me wiring and also to power would allow it to open and close the circuit as detected (in theory). That's a great suggestion. Thanks! I'll play around with that some.
Not quite. If you're using David's suggestion, you need to wire the relay to the "try me" wires, and the PIR is connected to the "trigger" side of the relay. You're looking for something like this: http://www.ebay.com/itm/HC-SR501-PI...826994?hash=item4d359aeb32:g:d54AAOSwH71XOsy-.

If you want to try to wire the PIR directly to the "try me" switch, you have some other considerations.


And like I indicated above, either way you go, it may be flaky because of the different voltages the components use. If that happens, there are workarounds.

J-man said:
Unfortunately it's not that simple. A Pir continually goes off whenever it detects motion, so it will continually set off the "try me" connection. Pressing the "try me" button starts the sound track, pressing it again while the audio is playing stops it. Pressing it again restarts it, you see the dilemma here.
There isn't a delay or interrupt built in the prop nowadays? I guess that would require some code or another wire, wouldn't it? Lame. So he needs to add a microcontroller to the project, and I have yet to find a project that can't be made cooler by the addition of a microcontroller. Or I suppose the sound sensor would need to be connected to some kind of timing circuit or you'd have the same problem.
 

·
Registered
Joined
·
126 Posts
Discussion Starter #12
The try me switch only works to turn it on, not off. When you press it the wolf howls 6 times and quits. Pressing it again when the wolf is howling does nothing. Does that change anything?
 

·
Registered
Joined
·
3,734 Posts
The try me switch only works to turn it on, not off. When you press it the wolf howls 6 times and quits. Pressing it again when the wolf is howling does nothing. Does that change anything?
Yours must be different than all of the ones I've tried in the stores.
 

·
Registered
Joined
·
57 Posts
I tried one this morning at HD. Each press of the button turns it on, and a subsequent press turns it off. If yours is a "fire and forget," then you can use the PIR relay idea.
 

·
Registered
Joined
·
476 Posts
Yup, mine turns off with the second press as well.

I've also noticed that the try me activation on the gray hound is much shorter than the sound activated. It only plays a few seconds compared to a min or so with normal activation. Haven't tested it out on the wolf yet but might be something to look out for.
 

·
Registered
Joined
·
256 Posts
That is good news the the OP's prop doesn't turn off with the second press of the try me button. So a PIR and small relay may be all they need for this.

As for the 5V vs 4.5V issue, you can put a diode (I'd recommend a 3A type such as the 1N5401) in series with the 5V supply to drop the power down to around 4.3V for the prop. The cathode (banded end) of the diode goes towards the prop. I've done this many times and it works well.

The PIR and relay can still be run directly from the 5V supply. I can do up a diagram if need be.
 

·
Registered
Joined
·
57 Posts
^^Or get a 12v PIR/relay and power the sensor side with 8 AA batteries. If he's using a relay to pass the prop side power, it doesn't really matter what the sensor side voltage is as long as it activates the relay.
 

·
Registered
Joined
·
126 Posts
Discussion Starter #18
That is good news the the OP's prop doesn't turn off with the second press of the try me button. So a PIR and small relay may be all they need for this.

As for the 5V vs 4.5V issue, you can put a diode (I'd recommend a 3A type such as the 1N5401) in series with the 5V supply to drop the power down to around 4.3V for the prop. The cathode (banded end) of the diode goes towards the prop. I've done this many times and it works well.

The PIR and relay can still be run directly from the 5V supply. I can do up a diagram if need be.
If drawing up a diagram isn't too much hassle, that'd be great.

As far as power goes, couldn't I just use a 9V battery? I'd only need it to work for about 4 hours.
 

·
Registered
Joined
·
57 Posts
If drawing up a diagram isn't too much hassle, that'd be great.

As far as power goes, couldn't I just use a 9V battery? I'd only need it to work for about 4 hours.
It's not a question of how long you plan to operate it, but rather of the working voltage of the prop.

You may be able to run it off a 9 volt, but It depends on how you're setting it up. If you're using the PIR to trigger a relay which is connected to the "try me" line, then as long as the relay can be triggered with 9v, you'll be fine--the sensor-relay setup is designed to have two different voltages and current on each side of the setup.

If you're trying to put the PIR "in line" on the "try me" line without using a relay, then you most likely don't want to put a 9v battery on a 4.5v line (3 AA batteries = 3 x 1.5v ) because you could fry the electronics on the prop. The prop likely has a voltage regulator on it that would reduce the voltage (and so does the PIR), but without knowing for certain the voltage regulator specs, it's generally not a good idea to pump more than 5v down the line.
 

·
Registered
Joined
·
256 Posts
Here's a diagram that shows how to hook up a 5V PIR, 5V relay and a 4.5V prop and run them from a 5V power source.

Security PIRs have a normally closed relay output, so we need to use the normally closed contact on the extra relay to flip the logic around again.

The 1N5401 diode drops the 5V down to around 4.3V which is fine for the prop.

halloween_prop_5v_pir.jpg
 
1 - 20 of 64 Posts
Top