Something old and something new

While I’m logging data and waiting for it to become substantial enough to test another project with, I thought it would be nice to kill the time and start building some new sensors: motion, temperature and light.

My goal is to monitor the complete second floor. For the 3 bedrooms I want to monitor motion, temperature and light. The passage will only require motion and light, while measuring the humidity in the bathroom would be nice too.

So, for that I need the following:

  • 5 * motion;
  • 4 * temperature;
  • 5 * light;
  • 1 * humidity.

I already have the motion sensors (PIR), the temperature sensors (1-Wire DS18B20), light sensors (LDR), enough JeeNodes, so all I need is a new humidity sensor.

OK; the amount of sensors I want to use is a bit too much for a single JeeNode I guess. Maybe 2 JeeNodes will suffice? I didn’t do any math on this yet, but I don’t think a single JeeNode can do the job all on its own. 2 JeeNodes maybe, cause the temperature sensors can be on a single 1-Wire bus, so those sensors won’t use up much ports on the JeeNode; and maybe I can use an Analog Plug to measure the LDRs? We’ll see. But for now, I assume I’ll need more than 1 JeeNode. However, I don’t like to spend an XBee module on each of those JeeNodes, cause I want to keep it relatively low cost. Yeah I know, there are cheaper alternatives for XBee..

But wait, I’ve still got an Arduino Fio; I’ve bought it sometime in January, not for a specific purpose but just to have a look at it, and I never found a good use for it yet. This Fio is also based on the ATmega328P and runs at 3.3V and 8 MHz. And it also has an XBee socket and USB connector. And it’s getting old, gathering dust on the shelf…

Now why don’t I use this Fio as a ‘hub’, or ‘central node’? It shouldn’t be too hard to make the (1,2,..) JeeNodes talk to this Arduino Fio over a few wires and use the Fio to transmit all the sensor values to the Zigbee coordinator; now that would be nice! I could power this Fio with a small USB power adapter and run a few wires (for power and serial connection) to the JeeNodes. Maybe I could just as easily use 1 JeeNode per room; this leaves enough ports available for future expansion… well, let’s think this one over for some time!

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6 Responses to Something old and something new

  1. Michel says:

    Hi Robert,

    A Jeenode roomboard can do light, humidity, temp and motion. And on low power it will last for à long time……
    I can understand the Xbee pricing that’s why I just use the standard RF12B’s

    Rgds,
    Michel.

    • Hi Michel,

      I know the JeeNode Room Board, although I’m not actively using one myself. But since I’ve already got so many components already available, buying 5 JeeNode Room Boards would be a bit silly – it all has to be paid from the ‘hobby budget’ 😉

  2. Gijs van Dulmen says:

    Hey Robert,

    I use one JeeNode for outside and the shed. It contains:

    2 motion sensors
    1 reed switch
    2 DHT11 sensors
    3 DS18B20 sensors
    2 LDR’s

    Does it with ease 🙂 Connected to the mains. Still using RF12MB modules over here. With added encryption and ACK’ing everything it is doing well the last month (6 nodes). Have to figure out how much I missed … but I guess it’s less to zero.

    Greetings,

    Gijs

  3. J.Labots says:

    @GIJS:

    Could you please share the sketch….?
    And the exact components to….?

    Jacco

  4. Pingback: Building the sensor hub

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