Hello guys. I am after some advice please, nothing specific I am only at an ideas stage. I have to create a product that can be constructed in 6 3-hour sessions. The idea I have is for a gas/smoke detector that transmits a signal wirelessly to a computer in the event that the alarm is triggered.

The smoke detector I can buy off the shelf I imagine. Then I am sure I can piggyback the high-voltage to the speaker when the alarm sounds to trigger a transmission. What I am stuck on is where to start with the wireless system. What technology would be suitable and provide a lot of off the shelf components? Is there tech that can be controlled with a PC rather than microcontroller? Any advice would be appreciated so I can research it further.

Cheers
Fraser

 

...a gas/smoke detector that transmits a signal wirelessly to a computer in the event that the alarm is triggered.

Transmits how far?
A computer could be taught to listen for a smoke alarm - audio range.
Line of sight such as IR doesn't seem practical but is always an easy option.
Bluetooth would work for in-room distances but doesn't require line of sight.
A wireless network node or other RF would give 100ft or more
And so on...

I'm wondering if a hack of a wireless webcam wouldn't be the simplest approach. You can buy them pretty cheap - they're the new generation of baby monitor.

 

Thanks for the reply wayneh.

For proof of concept I would only be looking to transmit across a room, say. In this project the technology isn't too important it's more about product design and sustainability and all that jazz, however we do need something that works!!

Taking the webcam example...I'm not much of a hacker, how could I take a high voltage from the speaker of the alarm and use it as an ON signal? Getting a datasheet and hoping it has PCB info on there? I'm wondering if it might be simpler to use off the shelf Tx/Rx but to be honest I don't know what would be simplest in terms of coding/controlling. That's what I'm mostly stuck on.

 

... how could I take a high voltage from the speaker of the alarm and use it as an ON signal?

Well, FWIW I don't think that'll be a problem at all. First of all, it's not likely "high" voltage. Probably not more than 9V or so at the max. And anyway, converting the alarm signal to an "on" trigger is easy either way. By that I just mean that if I know how to do it, it must be easy.

I don't have a great answer for doing the transmission, but I know the technology in a webcam has already solved the majority of the issues involved. It's possible that just turning it on may be all that's needed to alert the PC that the trigger has been thrown.

 

This is really late to the game, and i don't know if you are still looking for a solution to this, but I realized after reading this that what you meant by 'high' voltage was more about the signal from the sensor to the alarm being on 'high' when the smoke is sensed (or heat, I'm not sure how they work). I would think that you'd be able to tie into that wire and then connect to an interrupt on an arduino or something along those lines. Then you could transmit a signal via bluetooth to your computer. You have some front end work to do at that point with getting the signal from something the computer can read (which most modern computers can do) to making it interact in a way that would be useful to you. But I thought that idea about tying your hot wire into an interrupt might be of use to you.

edit:grammar