Useful little sounder

[cedd]

Hi all

Thought I'd share this little discovery. Whilst working on a project at work I needed a 12v sounder for an alarm system. The environment is a pretty quiet one, so I wanted something I could adjust the volume on. I spotted this little unit in CPC's catalogue and as it wasn't my money I was spending, went ahead and bought one.

http://cpc.farnell.com/projects-unlimited/api-4260-lw150-r/buzzer-12-24v-dc-usb-programmable/dp/LS03925

 

It's a USB programmable sounder. You can upload your own mp3 or WAV audio files to it. The intention being you can pick the siren sound you want (there are some on their website) and just upload it. My intention was to take the files, edit them in Logic to make them the required volume, then upload them.

Of course, once something as interesting as this arrived in the office, we had great fun with it. Klaxon's, lightning, cats meowing, all the usual. Then I uploaded some vocal recordings I'd made of plain speech from the Narnia project I'm working on. I wasn't expecting much but was absolutely blown away. Don't expect full, rich sound from the thing - it's only just over an inch in diameter, but it was surprisingly good! Very clear, pretty accurate and able to achieve a level comparable with that of a real person speaking. With a bit of tweaking with the recording (I hadn't particularly maximised the level, it was speech metering very much in the bottom end of green on the meters in Logic) I reckon it'll give some really good results.

It's not going to be of much use to folk doing conventional theatre on a stage - unless it's a quiet play. It holds 30 seconds of audio and will repeat it until you cut the power.

 

My plans with them are to fasten them in the trees as you walk in to The Narnia Experience so that as you walk through, the trees are all whispering (the trees are the White Witch's spies). 30 seconds should allow me to build a few different audio files with timed silences so trees can have conversations. All I'll then do is fit a relay with a timer so once they've looped once, they'll stop. All I need to do is switch the DC.

 

Best thing is, they're only 12 quid. I'm going to be buying 10 of the things!

[alistermorton]

My plans with them are to fasten them in the trees as you walk in to The Narnia Experience so that as you walk through, the trees are all whispering

 

They have a similar effect at Kensington Palace where there are courtiers' whispers running constantly in the Queens's gallery and when you sit on certain cushions. Most disconcerting, I think it will be very effective for your purposes..

 

 

 

[Stuart91]

I like the idea of hooking some of these up to alarm relay contacts, in order to scare the life out of anyone foolish enough to break in.

[Glyn Edwards]

Do these just play when power is applied and stop when it's removed? Do they reset to the beginning of the sample on a power cycle, or continue from where they left off? Do they loop at the end of the sample?

[cedd]

Pretty much yes. They're designed as an alarm and a direct replacement for a standard piezo sounder. Apply power (12v or 24, or plenty of others for that matter) and they'll start sounding. Remove the power and they stop instantly. There's a bit of background noise as you'd expect from such a tiny amplifier, but it's nothing I'm finding particularly offensive. At the end of your audio file they loop, so I'd maybe look to include a reasonable length tail of silence to give you some safety margin. I'm planning on producing a 25 second long file (the limit is 30) with my various whispers, then the 5 seconds is a window during which my relay timer can stop and switch them off until the next person walks through the trees.

 

I plan on building the tracks in something like Logic on seperate tracks, so I can listen to the whole lot as a sequence to get timings right, then bounce individual tracks to produce content for each sounder.

[timtheenchanteruk]

hmmm, these linked to a standard PIR sounds fun, would solve the need for an external timer relay as well.

[cedd]

You'd still have to time the DC to them as the PIR would only give you a contact closure while it's detecting movement. These things don't have a trigger line as such, they just make sound while they've got DC. I do however have other devices in my box of tricks that will play a track on a trigger. I'll be doing another Narnia video blog soon which will include a section on a few of them. I'm having to keep it all a bit ambiguous as we're not wanting to give away too much, but I reckon I can get away with showing the "tools" as long as I don't show how we're using them.

[timtheenchanteruk]

I was thinking more of a PIR used for occupancy/outside lighting etc , they usually have a timer relay in them to keep a light latched on.