Computing stuff tied to the physical world

RJ11 daughterboard

In Hardware on Aug 24, 2009 at 00:01

For connecting the JeeNode to a bunch of opto-sensors to track energy, gas, and water consumption, I’m thinking of using RJ11 telephone cables. Not only is the 4-wire version of these cables easy to get and cheap, you can in fact get two cables by cutting them in half and connecting the loose wires to whatever you like.

Here’s a daughterboard idea which would make it very easy to use JeeNodes for such a setup:


This is a mockup – the pin distances do not fit the 0.1″ proto-board grid, but you get the idea. Should probably add a power-on LED as well.

The power jack makes it easy to attach any standard 4..12 V power adapter. The 6-pin FTDI connector on the side is only for re-programming the unit – it can be omitted if you flash the ATmega with the proper code before inserting it into its socket.

I’m not sure what to do about mounting such a unit, though…

Update – The term “RJ11” is not quite accurate. It’s a 6-pin socket (RJ12), which could be used either with 2 (RJ11), 4 (RJ14), or 6 (RJ25) wires connected, as described onĀ this page, for example. So it’s more like an RJ12 daughterboard, for use with RJ14 or RG25 cables.