REUK Super Timer with Light Detector Override

Pictured below is a new device which mixes the features of the REUK Super Timer 3 and the REUK Dawn/Dusk Lighting Controller.

REUK Super Timer with light detector overrideThe timer can be programmed with different ON and OFF time durations from 1 second to 99 hours with various modes of operation available. When the time is ON, there is a 12V output (rated at up to 1A) which can be used to control up to 10-12 Watts of 12V devices, or used to switch a relay if higher currents or different voltages are to be switched.

The modification is the addition of a light detector (light dependent resistor) which is used to override the timer at night time. When the ambient light level is measured to be less than the user set threshold, then when the timer is ‘ON’ the output remains off.

This particular board is for an automatic fish feeder which directly drives a small motor, and the override is to prevent the feeder operating at night.

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

Low Voltage Disconnect with LCD Display

Pictured below is our latest low voltage disconnect circuit with LCD display.

REUK low voltage disconnect with LCD displayAs with our standard programmable low voltage disconnect (LVD), this device is designed to protect batteries from being discharged too deeply and permanently damaged. The user can set the low voltage at which the output loads will automatically be switched off, and also the higher cancellation voltage above which the output loads will be switched back on again.

LCD display on REUK low voltage disconnect (LVD)This particular LVD has a backlit LCD on which system information is constantly displayed. It is also used when setting the low and high voltage thresholds which makes things  a lot clearer and simpler than using LEDs or a rotary switch to programme those in.

As shown above the display shows the measured battery voltage updated multiple times per second and given to 2 decimal places of resolution (and calibrated to be accurate to within +/- 0.02 Volts across the range 10-16V).

The system status is usually ON or OFF, but can also be LOW or HIGH when the battery voltage is transitioning one of the thresholds about to change the state of the system. The high and low threshold voltages are also permanently displayed.

In order to avoid the output cycling on and off too often (particuarly as the battery voltages can spike or dip depending on the loads they are powering) there is a time delay during which the voltage must remain under/over the voltage threshold before the system will change from ON to OFF or OFF to ON respectively. During that time delay the backlight of the display flashes as a visual indicator that the threshold has been breached. We chose to flash the display itself rather than flashing an LED either on the board or on leads, since it is much easier to panel mount just the LCD than to mount both that and an LED indicator.

This particular client-tailored LVD has a MOSFET directly switching the output loads which can have a maximum total rating of 3 Amps. We can also make this with a relay fitted on board for direct switching, or a lower rated output which can be used to energise a high current (or high voltage) rated relay external to the board – e.g. an automotive relay or a solid state relay (SSR).

This low voltage voltage disconnect with LCD is now available direct from the REUK Shop. Click here to find out more or to purchase now: buy REUK Low Voltage Disconnect with LCD.

We will shortly be adding a very similar unit with the addition of datalogging functionality. Over the last couple of years we have sold many LVDs with built in dataloggers (see here for an example: Low Voltage Disconnect with Display and Datalogger), and we now have refined things to the point that the product is ready for general sale. In the meantime, if you have any requirement for a low voltage disconnect with or without a display and with or without datalogging, please email neil@reuk.co.uk with details of your requirements.

Frost Warning Thermostat with Temperature Indication

waterproof thermostat frost warning devicePictured above is a project we have recently completed for a special thermometer thermostat for an automotive application. The requirement was for a device which would show the temperature using LEDs, and would sound a warning buzzer for a couple of seconds when the measured temperature falls to or below a user set temperature threshold (in this case chosen from within the range 3- 5 degrees Celcius).

ds18b20 stainless steel temperature probe - waterproof

A waterproof temperature sensor was required for this project, and good accuracy and reliability was also essential. Therefore we chose to use a stainless steel encased DS18B20 digital temperature probe – the same sensors we use in our swimming pool solar water heating pump controllers amongst other things.

The button on the circuit board can be pressed by the user to change the temperature at or below which the attached buzzer will sound. When the temperature is above 5 degrees, both red LEDs are on. When the temperature is below 3 degrees, both green LEDs are on. When the temperature is in the range 2.76 to 5.24 degrees the LED which corresponds to the nearest temperature to that measured it on.

If you need a thermometer or thermostat along similar lines to this unit, email neil@reuk.co.uk with details of your exact requirements. We can also add 16×2 LCDs (displays) upon request.

 

Solar Water Heating Swimming Pool Controller with Display

Pictured below is another of our solar water heating pump controllers – this time with digital waterproof temperature sensors (DS18B20), and an LCD to show the measured temperatures of the solar heating panel and swimming pool as well as system status and for the user to programme in the settings.

Solar water heating pump controller with LCD and maximum temperature overrideAs this controller is to be used in sunny Australia it includes a pre-programmed maximum temperature override to prevent the swimming pool from getting too hot. When the pool is measured to 31 degrees Celcius or hotter, the pump will not to be turned on again until the pool temperature has fallen to 28 degrees.

LCD display for solar water heating pump controller

Pictured above is the LCD showing the solar panel temperature of 26 degrees C, and the pool at 32 degrees C. Therefore the pool is too hot and even when the solar panel temperature increases, the pump will not turn on.

At the bottom of the circuit board is a pair of screw in terminals which will be connected to the output from a 12V programmable digital timer. In the winter, the customer for this controller wants to be able to automatically run the pump at the same time each day for a certain time just to circulate water around the system.

If you need a solar water heating controller for any application, with or without a display, email neil@reuk.co.uk with details of your exact requirements.