Hey guys, I need your help with some stuff. I want to build three kinds of switches, one that reacts to light, one that reacts to sound, one that activates wireless. Actually, I want another one that activates every X minutes. So what I want is a thing that will act as a switch, but according to the top things. 1) The first one must be some sort of photodiode. It must activate when a sudden burst of light is found, like lightning for example 2) This one must activate when there is a loud sound, like a glass breaking. 3) I don't know what the best method for this will be, RF? I was thinking something like the remote of a electric gate or something. 4) I assume on would use a 555 Timer and RC-Time values here? Can anyone point me in the right direction or help me design the circuits? Will I be using relays for this project?
The fourth is easy (the cheapskate way) Buy an analogue alarm clock, but have pins coming up at certain intervals, and attach a wire to the minutes hand, so the circuit is complete only for that miunte
Oh, no, you misunderstood my question. I want it to activate every X interval, not at a certain time period. I want it to close the switch every 5 minutes for example. Edit: Oh wait, I misunderstood your answer. That way could work, but I'm looking for something electronic Very good idea though, I would never have thought of that
555 plus random electronic components is actually cheaper. Transistors are your switches obviously. Also you can use a pair of headphones for #2 as they work as microphones as well. I'll let someone techie answer this though.
You could use a 555 monostable arrangement for the first 2, not sure about the third and you'd use a 555 astable for the last one. Gimme a day or so and i'll have the schematics for ya im off out to get drunk ya see!
Do you want the switches to stay activated after the flash/noise or just be on for the duration of the flash/noise?
Most of them are figured out here already: 1) ldr + transistor 2) microphone + transistor 4) 555 timer circuit All of these can circuits can have a little vr so the sensitivity of the first two and the time periods of #4 are adjustable, but i dunno what you want with #3 There's that much RF everywhere that if it was just an RF detector circuit, it would always be on, unless you are in a faraday cage or something like that. Did you want an infra red detector so you can trigger a switch by using any household remote control maybe?
Okay that would be fantastic! I know what the main components of the above mentioned are, but I have NO idea how to put it together, that's why I asked if anyone here can help me out. And with RF I was thinking something in the line of an Electric Gate remote + receiver. I know you get 1-4 channel remotes, all you have to do is change the dip-switches in the remote to comply with the receiver. But I was hoping there's a cheaper method than buying a kit. EDIT: Another thing, these circuits need to run off of 9V or 6V preferably.
The cheapest wireless one is probably a doorbell, I've seen them for under £10. First thought for the light/noise switch was a comparator, using either an op-amp or a true comparator IC driving a switcher transistor. A 555 has a comparator with hysteresis built-in, will sink/source plenty of current, and saves a few components.
Thanks for those links cpemma, I'll have a look at them. And the doorbell is a great idea! I think I will go for that!
