Ed and Jack – Energy Efficient Lighting


To summarise our project, we have produced a light switch module that automatically controls the lighting within a room. The purpose is to not only prevent, but change the behaviour of those who leave the lights on before leaving a room. The context being that it is a common behavioural issue, especially in the UK, that people do not consider the environmental impacts that leaving appliances on has. Leaving lights in wastes a considerable amounts of energy, and can be easily avoided. This automated lighting system is controlled by using a person counter to identify whether people are in the room or not. This is done by using two IR Sensor Modules. When the person count is 0, the lights remain off, when it is 1 or above they turn on. This is when the three way toggle switch is on energy saving mode. When the on or off options have been selected, the light will act as a conventional light. This enables the users to keep the functionality of a standard light, keeping the products use flexible. The other key feature to this product is the gamification. The light switch module recognises if the last person leaving the room has turned the switch off themselves. If they have, they get a point. If the person leaves the room without switching the light off; as they should, the module will get a point. This score will show as an ongoing percentage on the LCD display that features on the front of the product. If the light switch gets a point, a responsive sound will be produced. This will keep as a reminder every time they forget to turn the light switch off. Eventfully, the combination of the gamification and competition along with the reminder will increase the number of times that they will remind to turn the light off before leaving the room. The product heavily relies on the competitive human nature.


Final Design

Our final design consists of a white housing that holds all the electrical components. The aesthetic has been taken from other light switches, as home integration is key in the success of this product. A shiny, metallic silver switch situates at the top left. It contrast clearly enough against the white to make usability as easy as possible. The LCD display keeps central, to be as easily seen as possible from all directions, and the IR Sensor Modules locate at the bottom corners. There must be a space in between these for the directional person count to work effectively. Due to the size of the display, the moving score bar had to be removed. Clarity is significant in achieving the behavioural change, and this feature cramped the display.

Final Prototype


Final Code

The loop function contains a switch case machine which is run off an if statement based on the toggle switch position. Each toggle switch position corresponds to an action, namely:

In the “ON” position, the light is forced on and the lcd.off() function is run. This turns off both the LCD back light and the LCD itself. The automation() code is still called as the personCount needs to be kept count at all times..

In the “AUTO” position, the lcd.on() – turns the LCD back light on, automation(),  lights(personCount) – which allows the lights to be influenced by the number of people in the room, score()  and screen(pPercentage, cpuPercentage). The latter two functions deal with calculating the score percentages and with printing the information on the LCD.

In the “OFF” position, the LCD is turned off, automation(), score() and screen() are all run so that it can accurately increase cpuScore even when the screen is off.

The automation function contains the code that allows personCount to either increase or decrease. This in turn alters boolean variables that trigger the score and subsequent screen functions.

The score function contains an if() statement that only runs when two conditions, isRoomEmpty = true and wasRoomEmpty = false have been met. These two conditions are set in the automation() function inside the if() statement that only runs when the sensors are triggered. This prevents the score() function from getting stuck in a loop once personCount hits zero. Based on the current position of the switch and the two booleans, it will either add a point to playerScore or to cpuScore.

Using these two variables, this function then uses a map() function to work out what percentage of the total times the player and the CPU have won.

The screen function then takes the pPercentage and cpuPercentage from the score() function and prints them in opposite corners of the display followed by a ‘%’ symbol.



Final Circuit Diagram


Buzzer, IR Sensor Module (x2), LED, LCD, 3 Way Switch, Resistor (x2)



Potential Developments

We started this project with lots of ideas regarding how to incorporate different features into the final product. Some of which, have been left as concept due to feasibility, cost and time. Despite this, we have still kept in mind a lot of potential development options, as we believe as an idea, we could take this further.

Player Connectivity

If the product were to be bought, internet connectivity would be a good way of improving the overall interactivity. Doing so, would have a higher chance of enhancing the behavioural change. The website for example could display an overall leader board that links up to different products in different households. Displaying scores between neighbours would be an effective way of increasing the competitive nature of the product. Furthermore, the competition could exaggerate the gamification of the product. Other features that could be added through the use of the internet, include notifications via an app. The occupants of the house would download an app onto their smartphones, which would link up to their performance regarding how many times they have successfully turned the lights off before leaving the room. The app could also implement intra house competition. For example, a light switch module could be installed into every bedroom. Each user would compete, and due to the close proximity, the desire to turn the light off and win would be great. A Wi-Fi shield could be implemented to achieve connectivity to the internet, which is easily incorporated with the Arduino Uno.

Brightness Dimming

Initially we had the aim to use an LDR or another ambient sensor to measure the natural brightness of the room. However, testing the LDR proved that the component is not accurate enough. There are also many light influences in any room. The IR Sensor Modules are very sensitive, and not that tolerable to flashing lights. Another sensor that achieves this function but with more accuracy would be desirable for the consumer product. Another way of achieving automatic dimming, would be to use a spreadsheet that list the times of sunset and sunrise for each day. The Arduino would read the times, and a correlated brightness would be represented through the light. To incorporate this feature into a consumer product, the LDR would need to be calibrated in the situated room. The user would place the sensor in a suitable place within the room, that receives an average natural light brightness. This would be read and stored. The Arduino would be programmed so that the brightness produced by the room lighting would match a luminosity, so the room would remain a constant brightness all the time. This is done by using a Triode AC Switch. This dimming feature would increase the amount of energy the module saves vastly, as our initial research has already stated, “modern dimmer switches cut the supply on and off rapidly at hundreds of times per second – something called a TRIAC switch. This reduces the amount of power reaching the bulb, reducing the brightness. This does reduce the overall amount of power being used and therefore you could call them more efficient.”.

Computer Interaction

If the LCD display is increased in size and resolution, it would give us more opportunities in terms of content and detail. The clarity would be improved, so text would be more legible from a distance. Scrolling messages could be a development to build on the interactivity and competitiveness between the player and CPU. Including playful but taunting messages across the screen would provoke the user in a positive way. Messages that would notify them if they are winning or losing would evoke an emotional response, and their behaviour change would be enhanced further. This can be done by using the scroll function already programmed onto the I2C chip on the LCD.

Self Sufficiency

Another variation that we had in mind at the beginning of the project was to use solar energy. If the light switch module does not use any power from the mains, then the energy efficiency would be increased even further. Self-sufficiency would be a great selling point for product. Moreover, one of the aims for this project is to reduce the consumption of an appliance. Solar energy would not reduce energy consumption, but would eradicate any non-renewably sourced energy, and also any cost to run it. Household lighting tends to be used more when the natural light is low. Therefore, the capacitor connected to the solar cells will be more than likely charged up during the day, when the natural light is at its highest. In theory, if the solar energy is enough to power the module for enough time, it could be self-sufficient. The module could always be connected to both the mains and the solar panels for maximum functionality. If the solar energy produced is not enough to last an evening, the power can be taken from the mains.


In order to prove that this prototype conserves energy, an experiment would need to be conducted over a period of time. Installing it into someones house and recording the information would be good way of doing this. The product is finished and ready to use, so the reliability is not an issue. From clear day to day observations, and reports already written on energy wastage (see blogs), we know that people leave the lights on when leaving a room. So the problem is evident. The fact that the light is automated will reduce the energy wasted by cutting the power to the light when no one is present. This can be proved with simple mathematics. The psychology around gamification has been highlighted. Playing on the users typically competitive nature will trigger some sort of behavioural change. Whether this be due to annoyance or self determination. We strongly believe that this product conserves wasted energy from leaving the lights on when leaving the room.


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