Monthly Archives: October 2014

Raspberry Pi-Mote Mains Control

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We are currently reviewing the Pi-Mote from Energenie. This is a small Raspberry Pi compatible radio transmitter board which can control up to four 13A mains sockets. We are reviewing the starter kit which includes two radio controlled sockets and the Raspberry Pi transmitter board (pictured below).

Raspberry Pi Pi-Mote Transmitter BoardThe Pi-Mote simply plugs onto the GPIO pins of the Raspberry Pi (compatible with both Raspberry Pi B and B+ but for the B it takes up all of the GPIO pins) and then a simple provided Python script is run on the Pi to supply an identifying control code to each of your sockets so you can subsequently toggle them on or off individually (or all at the same time) as and when you desire.

We sell a lot of low voltage controllers designed to be used to control mains powered devices – e.g. pumps in solar water heating pump controllers and in rainwater toilet flushing systems, immersion elements, motors, lighting, heaters, coolers, etc. The benefit of the Pi-Mote is that it is completely unnecessary to mess around with any mains wiring – you just plug the mains powered device(s) to be controlled into energenie radio-controlled sockets, and then use software on the Raspberry Pi to control the devices remotely.

Energenie raspberry pi controlled mains socket

We will be conducting a thorough review of the Pi-Mote and writing some Python scripts to provide some real world examples of its potential uses for a detailed article coming soon on the REUK.co.uk website. In the meantime, click here for more information or to buy the Pi-Mote Starter Kit now.

Automatic Pump Timeout Circuit

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Picture below is an automatic timeout circuit we recently made for a rainwater collection system.

rainwater pump timeout circuitThis is for use within a rainwater toilet flushing system with 3000 litres of rainwater storage capacity and a standard header tank in the loft with a ballcock. The pump is a 12V pressure activated pump of the type common in motorhomes and boats. As the toilets are flushed, the ballcock drops in the loft tank and the pump automatically switches on to refill the tank with water from storage butts in the garden.

If the rainwater supply runs out then the pump will run dry okay, but if it is left running dry for too long it will burn out. Therefore a device was required which would automatically cut the power to the pump if it was detected as having run for too long – more than five minutes. (It was not possible to use float switches to detect low water levels in the water storage vessels due to their location).

Handily the chosen pump outputs a 12V signal while it is running, so this can be used to monitor the status of the pump without the need to detect the increased current draw through the cables when the pump is running or the sudden dip in battery voltage when the pump switches on etc.

The device we made is fitted with a 10A rated relay with NC and COM connections – therefore when the relay is not energised, NC and COM are shorted out inside the relay and the pump receives power. When the relay is energised, NC and COM are open and so the pump receives no power.

When the pump is detected to have started running, a timer starts. If this timer gets to five minutes then the relay is energised cutting the power to the pump to save it from burning out. An LED is used to let the user know that this has happened and they system has to be powered off and then on again to reset it after the pump has been checked and the water stores replenished.

As the rainwater storage is also sometimes used to water gardens from a connected tap, the device also has a manual override. Pressing and holding the button for one second triggers the override and then the pump can be run for as long as the user wants until the override is cancelled with the button.

If you require any kind of rainwater pump and/or monitoring system, email neil@reuk.co.uk with details of your requirements.

Poultry Lighting Controller with Low Voltage Warning

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We have been selling poultry lighting controllers for the last eight years designed to increase egg production during the long nights of winter. See here for details: Poultry Lighting Controllers.

Pictured below is a modified version of our standard Mark 3 lighting controller (sold here: REUK Super Poultry Lighting Controller) to which we have added a low battery voltage warning LED.

poultry lighting controller with built in low voltage warningThis modified version is designed primarily for use in lighting set ups where a solar panel is not used, and so the battery has to be charged by the user. When the battery voltage powering the controller and connected lighting falls below 12.0V, the red LED turns on to show the user that they need to recharge the battery as soon as possible to ensure reliable operation and battery longevity.

Contact neil@reuk.co.uk if you need any kind of poultry lighting controller with details of your exact requirements.

Low Voltage Disconnect with Dual Regulated Outputs

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Pictured below is a low voltage disconnect circuit with two individually switchable 12V regulated outputs ideally suited for use with voltage sensitive LED spotlights and similar in battery powered systems.

Low voltage disconnect with two regulated outputsThis device is effectively a dual output version of the 12V Regulator with Low Voltage Disconnect which we sell in the REUK Shop. Each output has its own low dropout 12 Volt regulator (LM2940) and can supply up to 1 Amp.

This particular dual unit is most suited to LED lighting scenarios in which there are two strings of bulbs which you need to be able to switch on or off individually – i.e. String 1 on, String 2 on, or both String 1&2 on.

Should the battery voltage fall below 11.9 Volts then the low voltage disconnect will cut the power supply to the outputs until the battery voltage has gone back above 12.5 Volts.

We sell a huge range of low voltage disconnects, 12V regulators, and mixtures of the two, so please contact neil@reuk.co.uk with details of your exact requirements if you cannot find what you need in the REUK Shop.