science club |
A web based reset button
Sometimes it is useful to reboot equipment remotely.
The avr web server is ideal for this. It is a small self contained
web server and it can easily toggle a relay to reset some other
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This article does not introduce new hardware. What is presented here
is just a slightly different software.
We use the normal avr ethernet board and the reset push button software which
is for download at the end of this article. You know the avr ethernet board
already know from
the article "An AVR microcontroller based
Ethernet device". To have a reliable galvanic separation between the
avr ethernet board and the equipment which we want to reset we can use
a small relay. E.g a reed relay. The connection to the relay looks as follows.
The diode D1 is needed to prevent damage to the circuit by relay coil induced
The switch contacts of the relay can then then be connected in parallel to
the reset button of the equipment which you want to be able to reset/reboot.
Most PC motherboard have dedicated connectors for the reset button. You just
connect it there. It is therefore very easy to reset a PC remotely.
How the web based "reset push button" works
To use this you just point your web browser to the ip address of the
of the avr web server.
You enter the password and press on the reboot button. This will show
a confirmation web page and at the same time toggle the relay for 1 second
to reset the connected equipment. This way you can e.g reset a PC or
a server or a DSL modem ... It's up to you what you connect.
© Guido Socher, tuxgraphics.org
2008-09-01, generated by tuxgrparser version 2.55