Monthly Archives: November 2014

Real Time Clock Timebase for Lazy Clock

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Pictured below is a timer we recently designed and built to act as an accurate timebase for a Lazy Clock (see here for details: Lazy Clock – PDF plans for this wood gear clock driven by a solenoid)

Real Time Clock with relay output for timebase of Lazy ClockThe device we made has a real time clock module based around the Dallas DS1307 Real Time Clock (RTC) – top left of the board pictured above. This can be set up (via the Arduino Pro Mini at the bottom left of the board) to output a 1Hz square wave – i.e. outputting a high signal for exactly 0.5 seconds followed by a low signal for exactly 0.5 seconds, repeating.

The device can be programmed by the user to close the on board relay for 0.25, 0.50, or 0.75 seconds, every 1, 2, 3, 4, 5..etc seconds using this 1Hz square wave as a trigger. The relay switches the solenoid which in turn keeps the Lazy Clock accurate to within a few seconds per day.

If you need any kind of relay timer, please email neil@reuk.co.uk with details of your exact requirements.

PIR Motion Sending Relay Controller for Security

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Pictured below is a PIR sensor based security system relay controller we recently made.

PIR Motion Sensor Relay Board for Security SystemWe make a lot of devices to interact with and monitor motion sensors – for example our user programmable PIR Relay Timer  designed for use with standard domestic PIR motion sensors such as the popular Honeywell IS-215T.

This controller pictured has a few added features specific to the requirements of the customer. A switch has been fitted so that the system can be armed easily when required. When the switch is closed, the user has 10 seconds to get out of the range of the motion sensor. While motion is being detected, the red LED is on, and after motion is first detected the yellow LED turns on and stays on. 10 seconds after motion is first detected the connected siren and strobe light are activated. Therefore the user has 10 seconds upon entering the protected area to disarm the system by turning off the switch (the location of which is of course unknown to intruders).

The user can programme in the duration that the siren and strobe lights will be on after motion is detected.

If you require any kind of system to interact with one or more PIR motion sensors, email neil@reuk.co.uk with details of your exact requirements.

New Raspberry Pi Model A+

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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)

Modified Solar Pump Controller for Solar Air Heating

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Pictured below is a custom controller we recently made based around our 2014 Solar Water Heating Pump Controller with LCD.

Modified-2014-controller

This device is designed to be used with a solar air heating system. There is one waterproof temperature sensor to detect the temperature within the solar air heating panel, with the second sensor mounted directly to the circuit board to measure ambient internal temperature.

Instead of the usual 1 Amp rated output for connection to a relay, this board has a relay fitted directly to it to directly switch the power to a 250 cfm fan which drives hot air from the solar collector into the house.

As with the standard 2014 solar pump controller, this device has an LCD display to show the temperature of the solar collector and (in this case) the ambient air temperature and system status information, as well as enabling temperature differentials to be set at which the fan will be turned on and then turned off and to control a manual override.

If you need a controller similar to this, please email neil@reuk.co.uk with details of your exact requirements.

New REUK Differential Thermostat PCB

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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.