In previous article, i wrote about controlling home appliances using GSM/GPRS devices. In this article, we learn about how to control home appliances using your smartphone (android) – Bluetooth module, micro controller, peripheral driver and Relays!
Think how cool it would be if you are able to control your AC appliances just with a touch of your Android smartphone. All you need to tap on your phone and you can easily switch ON/OFF your lights, fans and other home appliances. AVR micro-controllers provide a great platform to build such interesting projects and I have used ATMEGA8 micro-controller which is based on AVR.
Why prefer Bluetooth??
It is preferable to use bluetooth because nowadays people have their smartphones with them all the time, since the smartphones have bluetooth facility in them, thus it’s better to use bluetooth rather than using RF remotes or IR remotes.Have you ever seen people carrying remotes???
Using bluetooth has many of its own advantages :
2.Easy to use.
3.It works in short distance range(i.e. upto 10mtrs.)
4.Anyone can find free Bluetooth apps on android and many more.
Parts and components required as per the schematic provided:
1. ATmega8 micro-controller 1nos.
2. ULN2803 1nos.
3. SPDT 5v Relay 3nos.
4. V-reg 7805 & LM317 1nos. each
5. Terminal blocks 6nos.
6. Breadboard 1nos.
7. 5v Regulated Power Supply 1nos.
8. HC-05 Bluetooth module 1nos.
9. Resistors, capacitors, diodes, etc.
10. 16MHz crystal oscillator 1nos.
11. Some wires and jumper wires
12. Most importantly an Android phone with BluControl v1.0 or above installed on it.
The Bluetooth module used in this project is HC-05 Linvor Bluetooth module. It is an easy- to-use Bluetooth serial port protocol (SPP) module, designed for a transparent wireless serial connection set-up. The module has 34 PINS for configuration/interfacing of Bluetooth module with microcontrollers.
For setting up a bluetooth module, an i’ble can be found here. For creating 3.3v output for the bluetooth module, I have used LM317 IC v-reg with a 10k potentiometer.
ULN2803A : What and Why???
To drive a relay, we need the ULN2803A IC which is a high-voltage, high-current Darlington transistor array. The device consists of eight NPN-Darlington pairs that feature high-voltage outputs for switching inductive loads. The collector-current rating of each Darlington pair is 500 mA.
Applications of ULN2803a include relay drivers, lamp drivers, etc. And that’s what we need, relay driver. The ULN2803A has a 2.7-k? series base resistor for each Darlington pair which makes it operable directly with TTL or 5-V CMOS devices.
Read full article at Instructables.com – Click Here