hello
i have a question
i am working on a weather station
i am using 15 sensor arduino's and one base station
all arduino's are fed by a solar panel and a battery
and the base station has a power adapter
i cant give the code so far becaus of a crash (have to rewrite most of it)
but now comes my question
i can read all arduino's if i am next to it
but i need a conection trough a wire (i love if it would be one)
the maximum distance would be 30 meters
and i need the arduino's to send a id code firsth
if somone can help me get those 2 i can do the rest myself
i was thinking of just one wire with a 10K to ground and a transistor pulsing 9V trough it
I would think about using an I2C bus. Two wires instead of one, but it is a reliable, proven, robust technology with lots of products and tutorials. A Google search on "Arduino I2C" will produce everything you need. There is even an Arduino I2C library named "wire" in the reference or playground.
If you are going to string one wire you may as well string a double wire, like doorbell or speaker wire. If you use RS485 protocol that will be fairly resistant to noise.
With just two wires you could "drop" each station off the same pair of wires, and have the master station send down a query, go into listening mode, and get a response back.
Another approach would be to go wireless, if each station has a solar panel. If not, you might want to have a second pair of wires to send the power down to each station.
The length can be increased significantly by running at a lower clock frequency. One particular application - clocked at about 500Hz - had a bus length of about 100m (300ft).
I've run I2C approximately 50ft by using a low-capacitance cable and a slower clock.