Time Lapse Photography Controller

Posted on June 15, 2015 by neil

Pictured below is a time lapse photography controller we recently made for a customer who is using it at a remote site.

Rather than leaving the camera and MiFi (mobile Wi-Fi hotspot) constantly powered (necessitating a large battery), this controller turns them on only when they are needed – first MiFi is turned on, then 45 seconds later the camera is turned on, and then a further 15 seconds later a relay tiggers the camera shutter to take the photograph. The camera and MiFi are then left on for a further three minutes (so that the photograph can be processed by the camera and uploaded).

A programming button is provided which enables the photographer to take one shot every 5, 10, 15, 20, or 25 minutes etc, and once set up, this controller will run autonomously indefinitely, taking photographs at the required time interval and uploading them to the cloud server.

If you need a time lapse camera or similar timer controller, please email neil@reuk.co.uk with details of your exact requirements.

Heating Circuit Pump Controller

Posted on May 7, 2015 by neil

Pictured below is a controller we recently made for a wood fire cooker based heating circuit.

The controller itself is physically identical to our standard 2014 Solar Water Heating Pump controller with an LCD to display temperatures and system status and a couple of ds18b20 digital temperature sensors. However, it has been completely re-programmed for an alternative use.

The customer has an Esse wood fired cooker with a 2.5kW domestic water circuit. This thermosyphon water heating circuit feeds a 140 litre thermal store in which a heat exchanger is used to heat up domestic hot water.

As there is some surplus heat over domestic hot water requirements, a pump is required to divert surplus heat to a panel radiator situated below the tank.

Two temperature sensors are to be fitted – one in the middle of the storage tank and the other on the return thermosyphon flow to the cooker.

The controller we put together for this system measures the temperature of the two sensors, and if both are found to be above user set values (for example, 80C for the tank and 45°C for the return flow), then the pump will be turned on to divert hot water to the radiator. When either of the two sensor temperature subsequently drops 2°C or more below the set values, the pump will be turned off sending hot water back into the storage tank.

If you need any type of water heating system controller, email neil@reuk.co.uk with details of your exact requirements.

Hen House Door Controller with Sounder and Door Locking Solenoid

Posted on April 21, 2015 by neil

Pictured below is another special order hen house door controller we have made on request. Our standard dawn/dusk door controller is detailed here: Automatic Dawn/Dusk Hen House Door Controller. For this customer we have added a couple of new features – a sounder/siren and a door locking solenoid.

The door is opened and closed automatically using a light detector and some microcontroller logic to determine when it is dawn and dusk respectively.

30 seconds before the door opens or closes and while the door is in motion, a sounder goes off which will hopefully train the birds to realise that the door is opening or closing so that they know what to do; and a solenoid door lock is used to ensure that the door is kept securely closed at night time (since in this particular case a full size shed door is being used instead of the usual drop down bird-sized door).

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

Voltage Measuring Datalogger with micro SD Card

Posted on April 19, 2015 by neil

Pictured below is an Arduino-based datalogger we recently made for measuring the voltage output of induced EMF in coils through which a magnet is passing. The voltage output needs to be logged once per second for up to a few hours.

This particular datalogger is 12VDC powered, and will measure and log voltages up to 15VDC. (The induced voltage to be measured in this project has been measured with an oscilloscope not to exceed 5V).

Each time the datalogger is connected to the power source and to the coil to be measured, a new log file is created on the supplied 2GB micro-SD card. An on board reset button can also be used to start a new log file.

On start up or when reset, the SD card is initialised and checked to ensure that it is present and working properly. If it is not, the red LED turns on and stays on to warn the user – there are few things worse than running an experiment only to find that no data was collected. If all is well with the SD card, then once every second the coil voltage is measured and appended to the latest log file.

When the experiments are complete, the SD card can be removed from the datalogger and accessed via a PC for processing and analysis. The generated datalog files are simple text files with each measured data point on a new line in chronological order.

If you need a datalogger, email details of your exact requirements to neil@reuk.co.uk.

Dawn Dusk Hen House Door Controller with Timer Override

Posted on April 17, 2015 by neil

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.

This 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.

Double Controller for De-Stratification

Posted on April 4, 2015 by neil

Pictured below is a controller we recently made to de-stratify hot water cylinders. Stratification is the layering of water of different temperatures within a tank or cylinder. It leads to the problem of having a thin layer of extremely hot water at the top sitting above a quantity of much cooler water. Therefore any thermostats or temperature sensors on the cylinder will only see cool water (making the system inefficient), while dangerously hot water comes out of the hot tap.

This double controller is basically two of our 2013 solar water heating pump controllers put onto one board with a single power input. There is a top sensor and a bottom sensor for each cylinder to be de-stratified. (We used precision LM335Z temperature sensors for this project)

When the top sensor is measured to be a user set number of degrees (diffON) hotter than the bottom sensor, a circulation pump is turned on via the relay to mix the top layer of hot water into the cooler water below. This heats up the cooler water and cools down the hotter water giving a more consistent temperature throughout. The pump stays on until the difference between the top and bottom sensors has fallen below a second user set number of degrees (diffOFF).

With this particular controller diffON is set in steps of five degrees whereas diffOFF is set in steps of single degrees.

If you need any kind of temperature sensing relay controller or similar, email neil@reuk.co.uk with details of your exact requirements.

Automatic Plant Propagator Thermostat

Posted on March 3, 2015 by neil

Pictured below is a thermostat we recently made to maintain the temperature in a plant propagator fitted with 12V heat pads.

The propagator is located in a potting shed with two lead acid batteries charged a 40W PV solar panel with a solar charge controller. Our thermostat includes a waterproof stainless steel encased DS18B20 digital temperature sensor which is to be buried in the moist compost in the propagator. When the measured temperature falls below 17 degrees Celcius, the heating pads are turned on via the on board 10A rated relay, and then remain on until the temperature of the compost reaches 23 degrees Celcius.

Normally for these types of simple thermostat we use a PICAXE microcontroller, but we chose instead to use an Arduino Pro Mini as this meant that we did not have to deal with processing negative temperatures programmatically. (PICAXE only has integer mathematics, so cannot easily deal with fractions of numbers or negative numbers. If the propagator is not used for a while during the winter, below zero temperature could be measured as it is located outdoors.)

If you need any kind of bespoke thermostatic controller, email neil@reuk.co.uk with details of your requirements.

(See here: http://www.reuk.co.uk/wordpress/programmable-automatic-plant-propagator-thermostat/ for a user programmable version of this device for which different temperature ranges can be set.)

Automatic Alarm for Screen Printing Flash Dryer

Posted on February 20, 2015 by neil

We were recently commissioned to design and build an automatic warning alarm for use with a screen printing flash dryer by a custom t-shirt print company in USA.

A flash dryer is a special heater which rapidly cures the ink printed onto the t-shirt or sweatshirt. If a shirt is left for too long in the flash dryer it will be scorched and ruined, and with a bit more time even the wooden shirt board around which it is fitted can be ruined. Therefore it is desirable to have a warning alarm sound if a shirt is left in the flash dryer too long by the operator.

The controller we made is pictured above. There is a microswitch on the flash dryer which closes when the flash dryer is closed over a shirt. The user can programme our controller with the maximum number of seconds they want to leave a shirt in the dryer – e.g. 15 or 20 seconds – and then if that time is exceeded the on board relay closes for 3 seconds to sound a loud alarm connected to it.

When the operator opens the flash dryer, the microswitch opens and the controller automatically resets ready for the next time the flash dryer is used.

If you need any kind of automatic sensor or timer based alarm system, email neil@reuk.co.uk with details of your requirements.

Low Voltage Disconnect used as Charge Controller

Posted on January 31, 2015 by neil

Pictured below is our 12V Programmable Low Voltage Disconnect with Display as sold in the REUK Shop. The product is designed to prevent batteries from being overly discharged and damaged by automatically turning the load devices on or off depending on the measured battery voltage.

We recently made a few modifications to this design of this LVD for a customer to enable this device to be used as a charge controller; turning it into a high voltage disconnect.

There is a battery bank and a generator which is used to charge it. We replaced the standard 12V output on the low voltage disconnect board with a relay so that it could switch the generator on and off automatically. We then changed the code on the Arduino microcontroller so that the relay would open (turning off the generator) if the battery bank voltage exceeded a user set value, and would then close the relay again (turning on the generator) when the battery voltage fell below a second user set value. By doing this the batteries are well cared for – never being overcharged, and never becoming overly depleted.

If you require a low voltage disconnect or a modification made to one of our LVD products such as this charge controller, please email neil@reuk.co.uk with details of your requirements.

Programmable Low Voltage Automatic Battery Charger

Posted on January 29, 2015 by neil

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.

With 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.

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