For the past 6 months I have been working on a prototype UKHASnet node which is completely powered by solar. The aim is to install a UKHASnet node on the Redsands Forts out in the Thames Esturary where it will function independently both providing simple sensor data but also acting as a long range repeater. The Redsands forts were part of a larger set of WWII Anti-aircraft defences that were decommisioned in the 1950s but then used as sites for pirate radio. More recently Project Redsand has been repairing and preserving these 70 year old forts.
The Redsand forts can be seen from the North Kent coast as well as Essex and so a well placed repeater should allow a potential bridge over a significant distance. As the forts are difficult to get to the node will need to function independently and will need to be hardy to the elements. Project Redsand have kindly agreed to allow me to visit the forts when they go next and install the node.
The current node design is:
- Moteino R4 – arduino/RFM69HW
- 6V 2W Voltainics Solar Panel
- Adafruit USB / DC / Solar Lipo charger
- 2000mAh Lipo Battery
- 868Mhz Dipole Antenna
- Sistema Klip It Storage Container
The node has been installed outside in my garden for almost 6 months as I’ve tested various bits of software and settings. Currently it is install on the roof of our extension with the solar panel angled slightly and facing south east. The node will remain in repeating mode unless the battery voltage drops below 3.66 where it’ll go into a ‘zombie’ beacon mode. This setting has allowed the node to function for a number of weeks of winter weather with limited solar charging. For the last week it has managed to charge sufficiently to remain out of zombie mode.
The current prototype is named AH6 and can be followed on the ukhas.net website. It will continue to function in its current setup while I wait to go out to Redsand Forts and install the node – at that point I’ll change its node ID to RED0.