Students are eagerly searching for amazing science fair ideas. Here comes a wonderful science fair project for high school. The advantage of electronics projects is that it is less costly and you can simply afford that. We are familiar with iron box, it used in our daily life and an essential equipment in our home. Iron boxes consume more power around 1000 watts, once you forget to switch off the power, it may leads to huge power loss. How we solve this? Our new circuit gives you the flexibility to automate domestic Iron box. It will helps you to automatically switch off the iron box in any case if you forget to switch off it in your busy time schedule. The logic behind this circuit is very simple, that is it uses an LDR to sense the presence of your hand on the iron box. If you didn’t pick the iron box for a specified amount of time it will automatically switch off. As soon as you touch the iron box, it gets power.
You may also checkout our previous Top 10 Science fair projects ideas for kids
Circuit Diagram of Automatic Iron Box Project
Components for Science Fair Projects
- IC 4017
- IC 555
- Transistor (BC548 x3)
- Resistor (1KΩ x2, 2.2KΩ, 10KΩ x3, 680Ω)
- POT (10K)
- Capacitor (2.2µF)
- LED (White)
- Relay (12V/10A)
- 12V Power supply
Working Automatic Iron Box Science Fair Project
- Arrange LED and LDR in such a way that light will block when you hold the handle of iron box and light directly hit on the LDR when your hand is away from the handle.
- When you switch on the iron box and without holding the handle light from LED hits on the LDR and its resistance becomes low and the voltage drop across LDR is low.
- At the same time the drop across the 10KΩ potentiometer becomes high and enough to switch on the transistor
If the transistor is in ON state the collector voltage becomes LOW and it is fed to the RESET (15th) pin of IC 4017.
- 15th Pin of 4017 is an active high logic pin so the IC will be working normally (to reset we may apply 5V to the 15th pin).
- 4017 is a decade counter IC that is driven by clock from Astable multi vibrator, the outputs Q0, Q1… etc. will shifts the high values up to reset.
- Time being the Q9 is LOW hence the relay is in OFF state. So the electric power is connected to the iron box.
- Now 555 Astable muti vibrator is working and 4017 output is shifting from Q0 to Q9.
- This is the waiting time to take the iron box, if you do not pick it in this duration, high value reach at Q9.
- Pin 11(Q9) is also connected to the RESET pin of 555 IC (LOW voltage to RESET) using a transistor inverter.
- If high value (Positive voltage) reach at Q9 of 4017 will make 555 in reset condition, thus clock will pause as well as relay is in ON state. This will switch OFF the iron box.
- After you come back and touch the handle of iron box, Light block will occur thus LDR resistance increase and get positive voltage at pin 15 of 4017 (Reset), it will reset counter and start working.
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