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Guido writes -
Originally I wanted to write the next article about a weather station based on the avr web server. Based on a request from a customer I decided then to develop this circuit first. The weather station comes next. There are a number of interesting aspects/problems here which could also be useful for developing other circuits.
- Most LCD displays want 5V. The avr web server uses 3.3V
- The simple "switch on/off a relay" circuit which was the only function provided by the avr web server until now did not require HTML-forms. I used simply 2 URLs http://baseurl/password/1 for switching on and http://baseurl/password/0 for switching off. This does not work anymore for the display as we want to type a text into a web page which should then be shown on the display. What is needed is a needed is a proper decoding of HTML form data.
If you want you can use one of the I/O on the AVR to make a doubler. Then you can feed this into a 5V LDO.
Or there are lots of 3.3v to 5v converters out there. Since the current is so low it should be easy to find a suitable one (unless you try to power the backlight from it :)).
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I got this kit a while back (without the lcd) and it works great, I currently have a little avr ethernet webserver running, although it only switches an LED on and off atm. But, I'd be very interested in the AVR ethernet weather station. Especially if one can get some 1wire support on it ...
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