Hooking Up the Arduino Controller Box (Part 6)
We decided to mount the Arduino board (Freetronics EtherTen) and shield inside a IP66 rated plastic box. We could have mounted the Arduino inside the weather shield but it would have been a tight fit. This controller box gives us flexibility to add functionality and other features to the weather station. One of the next enhancements to the weather station is to convert it to Wifi communications with a solar panel for the power source.
We could have assembled the weather station controller in many different ways. We just used parts and components we had available in the workshop.
To provide power to the controller and sensors we are using power over the ethernet cable. We inject 12V DC via 2 spare pairs on the cable that are not used. Inside the controller we separate out the 12V and feed it into the screw terminal block mounted at the top of the controller box.
This 12V is used by the Hydreon RG-11 rain sensor and the Arduino board. We use a DC-DC Buck converter board to drop the 12V to 9V. We do this because the Arduino board power regulator runs hot if we supply 12V to it.
All of the other sensors require 5V and this is provided via the Arduino board. We take the 5V and GND from the board and connect it to the screw terminal block at the top of the controller box. All sensors requiring 5V are connected to this terminal block.
At the bottom of the controller box are 2 led’s. The green led is a power indicator. This is fed off the 12V via a 390 ohm resistor. The red led is used to indicate data is being transmitted to the internet. It is powered off digital pin 8 via a 220 ohm resistor.
Most of the sensors are connected to the controller box. We used the cable that was supplied with the Davis anemometer to connect to the controller box. For the Hydreon sensor we used a 4 core shielded cable.
We mounted the DS18B20 and BME280 sensors inside the weather shelter. The BME280 was mounted inside a box that sits inside the shelter. This box has vents in it to expose the BME280 sensor to the environment. Inside this box is a screw terminal strip that provides power and data signalling to both sensors. A 9 core shielded cable connects this controller box back to the main controller box.
The network cable is connected back to a switch. However we also inject power via this cable using two of the spare pairs. This is not true Power Over Ethernet and you can not use a switch that supports POE. We used a POE injection splitter cable as shown below. This was plugged into a switch port. The network cable from the controller plugs into the splitter in the female socket. We used a 12V plug pack to provide the power to the controller.
We did not use the splitter cable inside the controller as it took up too much space. We cut inside the network cable and extracted the power and ground pairs. These were then connected to the power terminal block mounted at the top of the controller box.
Coming up next …
We assemble the weather shelter.