Make your own Sensor Network device

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This is a placeholder for hints and tips on Sensor Network device development.

Contents

enclosure

Outdoor wireless sensor nodes need a water-resistant enclosure to protect the batteries and electronics from the rain. Underwater wireless sensor nodes need an even more water-tight enclosure. Do all the antennas and sensors work inside the box? If not, you'll have to put something outside the box, and somehow seal the connection between that and the electronics inside the box.

microcontrollers and radio transceivers

Some off-the-shelf Radio Transceivers include an integrated microcontrollers -- combining the two in one IC can reduce the net power required to operate the node.

The people developing early wireless sensor nodes (before integrated transceiver/microcontroller ICs were developed) were forced to use a single microcontroller per node connected to a single separate radio transceiver. Such a system -- or perhaps an external microcontroller added to a radio transceiver that already includes an internal microcontroller -- may be required if no off-the-shelf transceiver can handle all the requirements of a particular experiment.

Sensors

See sensors.

People developing wireless sensor networks have used a wide variety of custom sensors and off-the-shelf sensors.

Many people have independently come up with the idea of saving power by turning off the sensor most of the time, then turning it on briefly during measurements. Alas, a few sensors require a surprisingly large surge of power when they are first turned on. Alas, a few sensors require a surprisingly long time to "warm up" and "stabilize" from the time they are turned on until the time the first useful data can be pulled out.

Power

There are several strategies for dealing with the limitations of power sources:

  • batteries only, replacing as needed. Conceptually the simplest approach. May require very large, heavy battery per node if you want it to run unattended for long periods between battery replacements.
  • energy harvesting power sources only. Only collect data and communicate during times that power is coming in -- during times when the sun is up high enough to drive the solar panel, or when the air moves fast enough to spin the wind turbine, etc.
  • energy harvesting with battery backup. When external power is coming in, it is used to charge the battery. The battery stores enough energy to keep the node powered up and collecting data even when no external power is coming in. Some networks may stop communicating when no power is coming in, buffering up the collected data until external power returns.
  • ... other strategies ...
  • ...

Batteries

See power/Batteries.

energy harvesting power sources

  • solar panels
  • harvesting energy from mechanical vibration[1]
  • ... other power sources ...
  • ...

Further reading

You'll probably want to check out the current off-the-shelf WSN Platforms. Perhaps one of them already will work perfectly for your application. If not, perhaps you can still adapt one or more of the open-source platforms listed there -- -- adding stuff to improve functionality, removing stuff to reduce cost -- such as Meanwhile you could visit a somewhat outdated site about an open hardware design project: Hoarder Board

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