The idea of making this Power cut/on indicator came because of a real time problem faced in DIC (Design Innovation Centre) department of Vigyan Ashram, Pune, India. The battery in DIC department provides backup power supply for Classroom, Computer lab, Sewing section, Conference room, and Innovation development room during the power cut. But the switching from grid power supply to battery supply happens automatically the users don't know when it happens, due to this continuous use of electrical and electronics appliances causes battery draining in just few hours (i. e. 4 to 5 hours). Sometimes the power cuts are very long and continues till 7 to 8 hours. So once the battery is drained then electricity supply stops suddenly then everyone realises about power cut and battery drain. Users lose their important work at hand and everyone needs to wait until power supply comes back which is also a waste of time.
If the users know about power cut and switching to battery mode immediately then they can continue with the important works first leaving the other works which consume electricity more (like sewing machines, some computers).
So the task in front of me is to make an indicator which gives an alarm sound and also a light indicator in each section showing the status of battery and mains power supply.For light indicator simply a relay and led bulbs are used. For alarm indication a buzzer with Arduino Uno is used. In this instructable am going share the step by step procedure to make this.
Note: All the connections and wiring must be done after switching off battery and mains supply as it involves Ac 230 v connections. Safety and security precautions must be followed strictly without fail.
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Step 1: Components and Tools
Step 2: Giving Connections
For Light indicator:
This requires a 5 V relay, three 0.5 W, 230 V AC LED bulbs, connecting wires and a 5 V DC mobile adaptor to be connected as shown in the Image. Here I need to show the indicators in 3 sections of department so I have connected 3 LED bulbs in parallel. Depending on the requirement one can use 1 or more bulbs in parallel.
For Alarm indicator:
This requires Arduino UNO board with buzzer and Two 5 V DC mobile adaptors as shown in the connection diagram.
Overall connection diagram with Light and Alarm indicator:
Supply to the relay and input signal for arduino both are 5 V DC from mains/grid supply, So these two are connected in parallel as shown in the diagram.
Note: wire stripper and cutter is used where ever needed w.r.to the connections to strip the insulation at the time of giving connections.
Step 3: Programming
A beginner who is new to Arduino can learn about it using online tutorials and example programs in the Arduino IDE software. This program uses very basic commands to turn on the buzzer for 10 seconds when the power is off and turns on the buzzer with 4 beep sounds when the power is on. Once the program is written it is uploaded to Arduino board with buzzer.
connections to be considered in program are:
- 5V mains supply wires from mains adaptor : '+' terminal connected to digital pin 8 and '-' pin connected to ground pin.
- Buzzer '+' terminal connected to digital pin 13 and '-' terminal to the ground.
Refer the program used for buzzer with arduino:
Step 4: Casing
A casing is made enclosing arduino and relay module using mdf material with opening slots for buzzer and Supply wires from adapters. Softwares used are solidworks for designing and RDWorks for laser cutting. Following are the steps to make casing:
- What are you going to put inside the casing? - list down the components/ wires which need to be inside casing. Here we are going to need casing for Arduino Uno board with buzzer and a single relay module along with connecting wires.
- Measurements: take the length, width, and height measurements of components which need casing. Here I measured dimensions keeping altogether (arduino board, buzzer and relay module with connecting wires) and got the dimensions of box as 10 cm * 6 cm * 3 cm.
- Making holes for incoming and outgoing wires and buzzer: Arduino board need input supply so a 1 cm square is made on the left side face of the box for arduino cable. On the back side right corner a 1cm square is considered for relay load (bulb) connecting wires. On top surface of the box a circular hole with 1.1cm diameter is considered for buzzer. It is also used for supply wires of relay module.
- Solid works: Now do the designing in solid works software. A first time user of the software can refer the basic examples and tutorials given in the software for understanding.
- Once the designing is done save the each face of the box like top, bottom, right side, left side, front and back planes of the box in DXF file format. Make sure that all the dimensions given in the design are correct before saving.
- Now import the saved DXF files in RDworks software and connect your system with laser cutter. Make sure you have enough mdf sheets for cutting the box.
- Once you make sure that laser cutter is ready for cutting give go ahead with cutting process of each plane/face of the box as you designed.
- Collect the 6 faces of the box from laser cutter and then join them using glue/fevi quick to form the box. Now the box is ready.
Step 5: Installation and Working
The final installation is done as shown in the figure below:
- The left side of the DC adaptor is Mains supply connected and it provides a input signal for arduino and supply for relay.
- The right side DC adaptor provides supply to Arduino from battery/UPS continuously.
- The whole setup must be insulated properly for safety reasons.
- It must be kept out of reach of children.
Now when ever light/mains supply goes off buzzer gives buzzes continuously for 5 seconds and then gives 5 beep sounds. The red LED bulb in each section glows indicating battery is on while grid supply is off.
when light/mains supply turns on buzzer gives only 4 beep sounds. The red LED bulb in each section turns off indicating battery is charging while grid supply is on.
Please feel free to ask any doubts/questions. Thank you.