28.3 °C

About This Weather Station

Transmitter Battery OK
WeeWX version 4.9.1

This website is automatically updated in 5 minute intervals. Data is collected by a small station on site!

If the conditions are looking good, be sure to check our calendar to see if we're racing! Head over to our club site for all the details.

Weather observations are also posted to the following websites:

About the project

The location of the track means there is no readily accessible mains power and so the whole system relies on its own power and connectivity to the outside world. It is robust enough to handle breakdowns in cellular connectivity, days with little sunlight for solar charging and of course the weather conditions of where the system is installed. The following describes how the system is working today.

The weather head (pictured left) reports to a Raspberry Pi SBC (Single Board Computer) through SDR (Software Defined Radio) on 433 Mhz sending wind, temperature, humidity, light, UV and rain information. The SBC is secured in a lockable IP66 weatherproof cabinet welded to a pole with the whole system being powered by a SLA (Sealed Lead Acid) battery. Inside the housing box we monitor internal humidity, pressure (barometer), internal temperature, CPU temperature, CPU load, voltages/current output of the solar panel and voltage/current input to the battery. Energy consumption and production as a whole is also monitored (see below). Connectivity is provided through the 3G/4G network with an external antenna for range.

Measurements you see on this site are taken directly from this system; cloud base and wind run are calculated based on the readings of other sensors. The forecast is sourced from Arias weather who provide access to their data in exchange for data collected by this station - it is specific for the SA Blokart Club location.

The camera is a recycled security camera housing, modified to fit a Raspberry Pi camera inside. It takes photos every 15 minutes and uploads them to a server where windy reads them to produce the time-lapse graphic you see. The standard camera uses an analog ribbon style connector which we have extended via the creative use of a HDMI cable. This provides one more element to assess track conditions remotely, and also provide viewers from afar a look our club in action (on race days at least!). The image quality is carefully chosen and is a balance between usability, data usage and expense.

The battery powering the system kept charged via an MPPT solar charge controller connected to a 12v solar panel. Voltage drop down controllers are used to power the SBC, external and internal sensors, the cellular modem and the weather station itself.

To ensure longevity of the system, actual writes to the SD card are kept as infrequent as possible, images and files are stored in memory before being sent to the remote server where you are viewing this page from. We had investigated using an SSD (Solid State Disk) which worked fine, but drew too much current to handle overnight followed by days with little/no sunlight. In further reducing power requirements we moved the system from the Raspberry Pi 3B+ used in development to a much older Raspberry Pi 1B which draws significantly less energy and can still handle the workload - only just though.

The software running the station is the open source WeeWX package, with a number of customisations. These include the graphs shown, interfacing with numerous sensors right down to the implementing the SDR to support for this weather head. The front end layout on-top of WeeWx is provided by the Belchertown theme, to which a number of SABC specific modifications have been made.

Every 5 minutes the system will compile the readings over the last 5 minute period and generate JSON data files representing the current weather; once a day readings for yesterday, last week, last month and this year will be compiled and updated. These data files are then sent to an external server to be loaded by the site you are seeing now. In order to make the system more rugged we are constantly monitoring its cellular connection, and have automated methods in place to reconnect when it drops out.