Solderless Power Supply Module for Breadboard

We recently came across this handy little power supply module designed and built for use with prototyping breadboard (MB102 size) by YwRobot in China.

breadboard power supply moduleThis is a very useful device for anyone getting started with electronics thanks to its low cost (approximately £1 delivered) and ease of set up and use.

The module simply plugs into a breadboard and gives two pairs of rails which can be configured to give you 2x5V rails, one each of 5V and 3.3V, and you can also set one or both pairs of rails to 0V.

mb102 breadboard power supply modulePictured above we have used the small yellow jumpers to set one pair of rails to 3.3V/0V, and the second pair of rails to 5V/0V. The board is then ready to supply a few hundred mA at 3.3V and 5V to any project you may want to prototype/build on the breadboard.

The module is powered via USB. Virtually everone now has a micro-USB charger at home for mobile phone and table charging etc, so it is surprising that they chose to use a full size USB-A connector. It would have been much better to go for a micro-USB connector.

The module has two low drop linear voltage regulators to supply the 3.3V and 5V outputs. When we tested this with a USB power supply outputting 5.46V, we measured 5.123V on the 5V rail, and 3.286V on the 3.3V rail.

If your USB power supply provides less than 5V (or more likely, you have less than 5V after losses in a long/cheap cable) the 5V rail will always be a few tenths of a Volt lower than the incoming voltage – therefore you cannot guarantee a reliable 5.0V output from this module when powered via USB. Similarly, it is best not to use this connected to a USB port on a PC as the voltage of PC USB ports can jump around a lot depending on what the PC is doing at any particular instant.

There is however a standard DC barrel jack for DC input power. Using a standard 6V DC power supply should give you a full stable 5V output from the module.

There is an on/off switch on the module, with a green LED to show the current status. This is useful not just because it saves you from having to unplug or switch off your USB power supply at the power point, but also because the capacitors in a power supply retain charge after you unplug the power supply and this charge will feed through the module into your electronics project until those capacitors have discharged. That could have unforeseen consequences as the voltage input to your circuit drops.

The quality of the components used and the build quality are as you would expect from a product offered at such a low price, but these modules are still an excellent first purchase for anyone interested in circuit prototyping.

These modules are available on their own, or together with a suitable breadboard and jumper links as a complete starter package. Click here for more information or to make a puchase of one of these power supply modules.

Dawn Dusk Hen House Door Controller with Timer Override

Pictured below is a hen house door controller we recently made for a customer which is a modified version of our standard Dawn Dusk Hen House Door Controller.

hen house door controller with light detector and timer overrideThis controller will automatically open a hen house door at dawn and close it again at dusk. Dawn and dusk are detected via a light detector, and the user can calibrate the light level at which they consider it to be the transition between day and dusk and between night and dawn to meet their needs.

The modified version pictured above has the additional benefit of a programmable digital timer. We make hen house door controllers with light detectors which automatically detect dawn and dusk, and we also make them with programmable digital timers so that the user can instead set the exact time that the door is to open and close. This particular controller is our first which has both a light detector AND a programmable digital timer for maximum flexibility.

The purchaser of this controller expressed a wish to be able to have the hen house door close at dusk automatically, but also to be able (sometimes) to open the door later (or even earlier) than dawn. Therefore, in the summer when dawn could be at 4am, the timer can be used to keep the door closed until 6am or later to keep the noise down and avoid disturbing neighbours. The programmable digital timer we used can be set with different timings for weekdays and weekends, so for example, the door can be kept closed until much later in the morning on the weekend to keep the noise down.

If you need any kind of poultry door controller, email neil@reuk.co.uk with details of your exact requirements.

New Raspberry Pi 2 Model B – Six Times More Power

The new Raspberry Pi 2 Model B has just been released, and promises to be six times more powerful than the previous Raspberry Pi models.

Raspberry Pi 2 Model BThe original Raspberry Pi was released around 3 years ago, and since then technology has moved on and competitors have joined the marketplace. The single core 700MHz processor and 512MB of RAM of the recently released Raspberry Pi A+ and B+ make them feel quite sluggish and out-dated, and there are many applications which cannot be used as they run so slowly.

The new Raspberry Pi 2 Model B though has a quad-core 900MHz processor (ARM Cortex-A7) with a full 1GB or RAM,  effectively turned the Raspberry Pi into a low spec PC capable of running the new Windows 10 (which will be offered free of charge for Raspberry Pi to makers!) and the full range of ARM Linux distributions.

The new model is fully backwards compatible with previous models, it will just run everything much faster. You just need the new ARMv7 kernel version of Raspian, and all existing projects will work.

Amazingly, despite the huge lift in specs, the new Raspberry Pi 2 Model B will still be sold for just $35 (around £25-30 in the UK).

Get yours now (in the UK) at cpc.farnell.com.

Programmable Low Voltage Automatic Battery Charger

Our Mini Programmable 12V Low Voltage Disconnect (LVD) is designed to disconnect loads from batteries when the battery voltage falls below  a user set value, and then reconnect the loads when the battery voltage gets back above a second (higher) user set value.

low voltage connect from REUK low voltage disconnectWith a few modifications to the code on the microcontroller of this device it can also be reconfigured as a low voltage connect – a device which will (typically) be used to connect a charger to the battery when its voltage gets low, and then disconnect it when the battery voltage gets higher after charging.

Today we made such a low voltage connect for a customer with a semi off grid garden office, a PV solar charged battery bank, and a selection of lights, 5V chargers, and other low voltage DC loads to be powered. He has a mains powered 5A bench power supply which he wanted to automatically connect to the battery bank via a solid state relay (SSR) when the battery bank voltage fell due to a period of poor solar generation (English weather) or from using a lot of battery power.

With our low voltage connect controlling the SSR, the battery bank will never be able to get overly-depleted and battery power will always be available to power the garden office.

If you need any kind of low voltage disconnect, low voltage connect, or high voltage disconnect etc, please email neil@reuk.co.uk with details of your requirements.

Poultry House Door Controller with Digital Timer

One of our most popular products is this Dawn Dusk Automatic Hen House Door Controller. This device automatically detects dawn and dusk using a light detector calibrated by the user and runs a motor one way in the morning to open a hen house door, and the other way in the evening to close the door. Roller limit switches act to ensure that the door fully opens and closes without over or under running.

Pictured below is a alternative but similar device which uses a programmable digital timer to set the times of day that the door is to open and close.

Automatic hen house door controller with programmable digital timer and roller limit switchesWhen the timer turns on, the motor runs to open the door until the upper roller switch closes. Then when the timer turns off, the motor runs to close the door until the lower roller switch closes.

The advantage of using a timer is that the door can be set to open later on weekends for example to reduce noise from the birds, and the exact times the door is to be opened and closed can be set independently of the level of daylight (and therefore of the weather). The disadvantage is that the timings have to be changed every few weeks as the seasons change and the days get longer and shorter.

If you need any type of automatic poultry house door controller, please email neil@reuk.co.uk with details of your exact requirements.

Rainwater Toilet Flush Pump Controller with Overrun Protection

We make a wide selection of rainwater toilet flush pump controllers for domestic use, and pictured below is another of these.

Rainwater toilet flush pump controllerThis particular controller is designed to be used where there is a very large amount of rainwater storage and a relatively small header tank. In this scenario, if the float switch which detects whether the header tank is full were ever to fail or get jammed with debris etc, 1000’s of litres of stored rainwater could be pumped out through the header tank overflow and lost.

In this controller, the user can programme in a maximum pump running time. If the pump ever runs for longer than that time, it will automatically be turned off, and will not turn on again until there has been manual intervention from the user (checking over everything and resetting the controller).

In standard operation, the controller simply checks the status of the header tank float switch located just below the tank overflow outlet, and shows this status with an LED indicator. Once every four hours, the controller tops up the header tank by turning on the pump and running it until the header tank is detected to to be full.

If you need any kind of pump controller, please contact neil@reuk.co.uk with details of your exact requirements.

New Raspberry Pi Model A+

Pictured below is the latest Raspberry Pi – the Raspberry Pi Model A+ which replaces the old Model A.

Raspberry Pi A+ ModelAs with the Raspberry Pi Model B+ released back in July 2014 (see here: New Raspberry Pi Model B+), the Model A+ has the 40 GPIO pins, reduced power consumption, modified composite video, and a micro SD slot, but the Model A+ still only have 256MB of RAM compared to 512MB for the B+.

The Raspberry Pi Model A+ is smaller than all previous credit card sized Raspberry Pi’s being a whole 2cm shorter in length.

With just the one USB port and no ethernet port, if the Model A+ is to be accessible over your network, you will need a USB WiFi adapter as pictured below installed in the A+.

Raspberry Pi A+ Model with USB WiFi Module

It is likely that the Model A+ will primarily be used as a headless device, but initial set up of Wi-Fi still requires a keyboard and display to be connected – a USB hub is useful at this time. With everything configured, the Model A+ is ready for embedding in your projects.

The following is a very useful guide from How-To Geek which shows how to set up Wi-Fi from the command line: How to Setup Wi-FI on Your Raspberry Pi from the Command Line.

The Raspberry Pi Model A+ is available in the UK for around £17, considerably cheaper than the £27 Model B+. (Both best priced from cpc.farnell.com)

New REUK Differential Thermostat PCB

Pictured below is the latest (November 2014) version of our Differential Thermostat designed to be used in simple solar water heating systems, fan controllers moving warm air to cooler areas, and many other applications.

REUK Differential Thermostat - for solar water heating and fan control etc.This device is based around this solar water heating pump controller design which we have been selling now for over 8 years. When the left hand side temperature sensor is measured to be hotter than the right hand side sensor, the up to 2 Amps output is turned on, and remains on until the temperature difference between the two sensors has fallen to zero.

Connection diagram for REUK Differential Thermostat - new version Nov 2014This output can be used to directly power small pumps or fans etc, or can be used to switch a relay which can in turn switch high current or higher voltage devices.

Click here for more details and/or to purchase this new Differential Thermostat from the REUK Shop.

Raspberry Pi-Mote Mains Control

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.

East West Solar Water Heating Pump Controller

We have recently finished work on a new solar water heating pump controller to be used where the array of solar water heating panels is split between an East and a West facing roof instead of the more typical single South-facing (in the Northern Hemisphere) solar array. This controller has been based around our 2014 Solar Water Heating Pump Controller with Display with some additions and changes.

Solar water heating pump controller for use with an East / West solar arrayThis controller has connections for three waterproof digital temperature sensors – one for the East array, one for the West array, and one for the hot water tank (or pool).

The customer for this controller did not want to have the water flowing through both solar arrays at the same time to prevent heat collected on the hotter sunny side of the roof from being immediately radiated away from the cooler side. Therefore his system features two solenoid water valves which, when the pump is turned on, will ensure that water only flows through the hotter of the two solar heating arrays.

Display for East / West solar water heating pump controller

The display (LCD) for this controller shows the three measured temperatures on the top line, the temperature difference between each solar array and the hot water tank (or pool), which if either of the valves is open (therefore also indicating that the pump is running), and the temperature difference (diffON or diffOFF) required for the system to change state (i.e. for the pump to turn on or off).

In the above photograph, the valve on the West side is open, and the west solar array is +5.8 degrees Celcius hotter than the hot water tank. When this temperature difference falls below 4 degrees (diffOFF), as the East array is relatively cool (just +1.2 degees hotter than the tank) the West valve will close, the pump will turn off, and the display will now show diffON – the temperature difference required before the pump can be turned on again. (If the East array had been hotter than the tank by more than diffON at this time then the pump would keep going, the East valve would open and the West valve would close).

This controller also has a manual override facility which lets the user force the pump to run with the East valve open, the West valve open, or even both valves open at the same time – for example while testing. The values of diffON and diffOFF can be set by the user as per the standard 2014 solar water heating pump controller.

If you need a controller like this (or any other solar water heating pump controller), please email neil@reuk.co.uk with details of your exact requirements.