This sample shows how to collect data transmitted from low-power devices, employing the simplest power management strategy. At least 2 nodes are participating, but up to 7 end devices can be engaged. There must be one and only coordinator, and the rest of nodes must be configured as end devices.
For simple node identification, define unique logical addresses by DIP switches. When setting 8 possible DIP combinations, keep in mind that:
| Node | DIP switches | ||
|---|---|---|---|
| SW4:1 | SW4:2 | SW4:3 | |
| 0 | OFF | OFF | OFF |
| 1 | ON | OFF | OFF |
| 2 | OFF | ON | OFF |
| 3 | ON | ON | OFF |
| 4 | OFF | OFF | ON |
| 5 | ON | OFF | ON |
| 6 | OFF | ON | ON |
| 7 | ON | ON | ON |
To start the application and to initiate the network push SW1 button on each node, starting with coordinator. Green LED is switched ON if the network is started successfully.
Coordinator organizes the network with its own 'unique' PAN ID which is determined by its MAC address (considering the 16 least significant bits). Besides, user can set PAN ID in flash memory or EEPROM. In order to join, end devices are scanning the network.
End device measures temperature each 10 seconds and sends data to coordinator if the absolute increment of the measured value exceeds 0.5°C. Flashing yellow LED is indicating that data are transmitting. After the transmission is completed, the end device falls asleep. Unconditionally, the current temperature value is also sent if SW2 button is pressed on an end device, regardless the current node mode (sleeping or active).
Coordinator never sleeps; it keeps sending the received temperature data to UART via USB (see connection settings).
In order to help understanding the application code easier, two different image files are supplied, intended for programming the coordinator and end device, correspondingly.
The source code and Makefile of Low Power Test application are located at
1.5.1-p1