During a particularly creative lunch we were discussing potential hackspace projects, one that stood out was hyper local weather reporting.
We would build a network of nodes, and use them to collect environmental information.
The idea is to keep these sensors as cheap as possible, meaning we can have as many as possible.
The choice of hardware depends largely on the choice of communication. This will determine power requirements and potential locations for the nodes.
These would have to contain some sort of wireless communication, of which we came to 2 options
- Using wifi on each device to return data
- Using a RF chip, or xBee module to create an interconnected network of nodes
These options have pros and cons
- Easily connects to home wifi
- Can be placed anywhere in the world
- Does not need to be in wireless range other nodes
- Data rate can be very high
- Can go into sleep mode for low power consumption
- Easy to code
- No need to worry about RF signals
- Wifi needs to be present
- Slightly higher cost
- Would be a more fun technical challenge
- Can have them running anywhere - forrest, beach, park
- No need for wifi connection
- Cheaper communication hardware
- Nodes need to be in RF range of each other
- Need to be on at all times, to propagate data through network
- Higher power usage
- Require more programming
There are three potential power options for this type of project - Mains power, plugged into a wall socket with cable running to sensor - Batter pack - Battery pack with solar panel to top-up charge
Mains power gives you a consistent power source, and will let you return much more data. This may be required if you wanted an RF based option, as the RF chip would have to be kept on most of the time, a solar panel may be able to give you enough power.
However using mains power will limit potential locations.
This could last for many months if it was big enough, and if the wifi option was chosen. This wifi chip could be sent to sleep between readings, maximising power usage. An RF option would not last very long with this power source.
This option could be placed anywhere, with no limits on it's location.
Battery + solar
A solar panel topping up a battery pack could potentially power the sensor for ever, especially if the hardware was designed to be as low power as possible. A low power RF circuit, or a wifi connection that slept between readings could be powered with this method.
This option is not limited in geographic location, as there is no need to plug it in. Direct sunlight would be required to keep the battery charged.
There are an array of sensors that can be used for this project. - Temperature - Humidity - Rain - Air Quality - Carbon Monoxide - Barometric Pressure - Light
The inclusion of these will ultimately come down to cost.
The first version of this node will likely use the following hardware
- Electric imp wifi + processor
- Mains power
- Temp Sensor
- Humidity Sensor
Last edited by Richard at 03:04am on 1st of April 2014