Electronics ? - What would I need to make.....
 

What would I need to make a small device which has a micro-switch which when activated emits a beep after maybe 10 seconds.

Switch, beeper, battery.... but what does the time delay ?

555.

Do these help?

http://forum.allaboutcircuits.com/sh...ad.php?t=17367
http://www.aaroncake.net/circuits/relaytim.asp

Haven't a clue myself. Was always crap at electrics. Though I did fix the old man's mobile today that was repeatedly switching itself on then off etc etc. Just used a pencil eraser and all was well.

Dave

PS: would have said 'used a rubber ...' but that's had connotations ever since I was a teenager sniggering at jokes along those lines ... :norty:

Another option: http://focus.ti.com/general/docs/lit...b&fileType=pdf

You'll need two - one to generate a signal which goes high for 10s after the switch closes, and another to then generate a beep of the required length.

John's suggestion of a 555 is probably better, though. See:
http://en.wikipedia.org/wiki/555_timer_IC

You'll still need two, though, for the same reason - suggest you use a 556, which includes both on the same chip:

http://uk.farnell.com/jsp/search/bro...atchallpartial

[edit]: you'll probably also need to drive the beeper with a transistor, and depending on what type you use, you may need a third 555 to generate an audio waveform to drive it.

I'll translate all that into dummy and see if I understand it later. Thanks :thumb:

Or use something like this maybe, along with the buzzer?

555 cmos timer ic. If you want a repeating cycle set it as a bi-stable or a one off action set it as a mono stable, with a trigger. Just a few external components to design the necessary circuit

Andy

If anyone's interested (and doesn't already know about it!): You can get a complete free SPICE simulator, which includes the 555, from Linear Tech at:

http://www.linear.com/designtools/software/ltspice.jsp

I use it all the time; they intend it primarily to help engineers design circuits around their power supply controllers (hence the alternative name SwitcherCAD) - but it also includes all the usual passive components and a lot of discrete semiconductors as well.

As a tool for learning about how circuits work and for prototyping a project like this, it's ideal :thumb:

:thumb: you could take over the world with a 555 ;)