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Wireless network bridge monitoring circuit...need pointers.

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Well, this is my first post here. I've puttered around with electronics for a few years, so I have a decent idea how to do basic things; I know my way around a soldering iron and PCB, breadboard, the usual.

Here's my current project:
I work at a wireless internet company. We use Linksys wireless bridges for some of our infrastructure connections. Occasionally, one will lose network association and drop its connection to the rest of the system. This is a Bad Thing, because when it happens, everything past the downed bridge loses internet connectivity. Now, the bridges have a green LED that indicates if they are connected or not. Instead of driving 10 miles out to our radio tower to reboot the bridge when it goes down, I want to build a monitoring device that will wait until the light has been off for about 20 seconds, then cycle the power to the bridge off for 2 seconds, then back on, thus providing a bit of self monitoring and repairing capability.

I do not have any programmable devices; PICs, whatever. I'd love to use them, but I can't. I think the best way to go is to use a pair of 555 timers set up to trigger when the input goes low (the signal from the LED detection circuit, which I know how to do).


As I understand it, this circuit will wait until its input falls below 1/3 of Vcc, then wait a period set by the caps and resistors used, then pin 3 of the 2nd 555 goes high. This is what I want; am I reading it correctly?


Phil Dekraker
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