‘Flex Sensor’ or ‘Bend Sensor’ is a sensor that changes its resistance depending on the amount of bend on the sensor. They convert the change in bend into electrical resistance – the more the bend, the more the resistance value.Flex sensors are widely used in various applications such as – Automotive controls, Medical Devices, Fitness Products, Virtual Reality gaming consoles, Animatronics, Robotics, etc.This tutorial aims to provide a detailed guide to flex sensor and its interfacing with Arduino.
Keypad Locking System with User Defined Password
In this keypad lock project I have used the AT89S52 microcontroller, one of the series of 8051 microcontroller by ATMEL corp. Here I’m using 4X4 keypad to take input from the user (to enter password) and display the corresponding results on a 16X2 LCD. Since AT89S52 doesn’t have its own internal oscillator, thus we need to provide an external crystal of 11.0592 Mhz to make it function able. I am using a 7805 voltage regulator IC to convert 9V to desired 5V output.
Controlling Appliances Wirelessly using RF Technology
Now a day’s everyone needs a device which could control appliances wirelessly. This makes us to operate them on our fingertips from particular vicinity with ease.This time I have done something like this, I have created a prototype of a device which controls 4 devices/appliances separately using RF (Radio Frequency) technology. The device comprises of two sections: Transmitting (remote) and Receiving part. The transmitting part works as a remote device to send the corresponding data to the receiver section. It further consists of 4 SPDT (single pole double throw) switch, one Encoder IC (HT12E) and a TX module (433 MHz). These 4 switches are connected to the 4 data pins of the encoder IC to generate a 4-bit data to be transmitted. The switches provide either high (+5V) or low (0V) signal levels.
Mosquito Swatter or Mosquito Racket
Definitely, mosquitoes are annoying and it can spread diseases also. The best way to destroy mosquito is electronic killing using Swatter. It eliminates the use of toxic chemicals. The mosquito coils and liquids do not kill mosquito but they repel them only. Mosquitoes will return back when the chemical disappears from the atmosphere. The swatter is…
Wireless industrial intruder alarm system
In industries, intruder alarms plays vital role in security. Existing industrial intruder alarms are wire based and alarms are placed on the wall. In this system a big alarm with loud sound works as alert. If some intruder enters then alarm activates and produces loud siren. Now consider another system. What if alarm is in hand of the security guards? There is only one sensor but there are several hand held simple alert alarms one with each security guard. Then it will become advance and impressive security system. But this is not possible with existing wire based system. To achieve this we have to transmit one signal to several alarms at a time and for that we have to use RF wireless technology. The new thing in this project is, it uses only one intruder sensing system and activates lot of hand held alarms. Means only one transmitter activates several receivers at a time.
Web-Cam controller in VC++
This is the most amazing and commercially viable project in which the web-cam attached to your computer will move in all four direction up-down and left-right with the help of your fingertips. The software written in VC++ will control two different AC motors with the help of computer mouse. The forward and reverse motion of…
DIY Circuit Diagram: Transmit and Receive Low Frequency Pulses using IR Modulator & Demodulator
The circuit presented here is used to transmit and receive low frequency pulses using IR modulator and demodulator. IR modulator takes low frequency pulses as input. It modulates them on 38 KHz carrier and transmits them through IR LED as 38 KHz IR light. On the demodulator side IR sensor detects (receives) 38 KHz IR light. It demodulates this 38 KHz pulses and recovers transmitted low frequency pulses. One pulse generator is built using IC555 to generate low frequency pulses. IR modulator is also built using IC555 and TSOP1738 IR sensor is used as IR demodulator.
Iron Box Power Saver
This power saving circuit is used to save electricity while ironing. The circuit will switch OFF the iron box when it is not in use. Once the ON time of the circuit is crossed, it will produce an alarm. If we press the Reset button at the time of alarm it will turned OFF the alarm and extend the ON time of the circuit to the next 4 minutes. This circuit will work as a reminder for those who always forget to turn OFF the iron box in this day to day busy life.In this circuit is build around NE 555(IC1), op-amp LM 358 (IC2) and few components. IC1 is designed as a standard monostable multivibrator and its trigger pin 2 is held high by resistor R1.LM 358 is configured as a comparator. Its non-inverting input (pin 3) and the inverting input (pin 2). Inverting pin 2 of IC2 is connected to voltage-divider preset VR1. Using preset VR1 we can vary the reference voltage at pin 2. Buzzer is connected to the output pin 1. Initially output pin 1 of IC2 is low.
Designing of Band Reject Filter
There are 2 cut off frequencies for band reject filter. First is the upper cut off frequency (f1) -which is the frequency below which all the frequencies are passed. The second is the lower cut off frequency (f2) – which are all the frequencies above this frequency are passed.Similar to band pass filter but the difference is f1 < f2. That means upper cut off frequency is lesser than lower cut off frequency. Two types of band reject filters are
Inverter Battery Charger with Cut Off
This Battery charger can replenish any kind of 12 V Inverter battery or Car battery and keep it in top condition. The charger never allows the battery to Over charge or Deep discharge. It automatically charges the battery when its terminal voltage drops below 12 volts and switch off the charging process when the terminal…
Op-amp Tester
Op-amp 741 is a very well-known as well as very usable IC in many of the projects like amplifier circuits, voltage follower circuits, current to voltage changer or voltage to current changer and many more other applications. So for the proper working circuit it is highly necessary that your op-amp works correctly. So here the circuit that will help you to check whether your op-amp is in good condition or it is faulty.
Alert!! New mail
Principle behind Circuit- This circuit is constructed with the help of much known IC NE555. In this circuit this IC work like a comparator. Pin 6 of the IC is lined with positive power supply. When pin 2 is less than 1/3 of the applied voltage output at pin 3 is high. Similarly the output…
E-Cricket
Principle behind E-Cricket Circuit- This circuit is mainly for cricket lovers who watch cricket game and want to play, but unable to play due to their phatic schedule or any reasons. E-Cricket circuit shows various stages of cricket like out, six and many more with the help of various LED’s. At the time when S1…
FSK Modulators using IC 555
FSK means Frequency Shift Keying. It’s one of the Modulation Scheme used to Transmit Digital Data using High Frequency carrier signal. In this Modulation Scheme bit 1 is transmitted using one carrier signal and bit 0 is transmitted using another carrier signal like· Bit 1 (logic high) is Transmitted using Carrier Frequency Fc1· Bit 0 (logic low) is Transmitted using Carrier Frequency Fc2It means Series of bits (bit stream) are transmitted with two different carrier signals used for bit 1 and bit 0.
Sequential code lock for automatic gate
The password based lock for any access control systems is very common now a day. If there is a password lock for any gate/door, then the gate or door only opens when correct password is entered. Mostly in such system numeric keypad is given to enter password. Sequential code lock differs here with normal password lock system. It does not have full numeric keypad with 10 to 12 switches. Instead it has 2 to 3 switches only.
DIY – DTMF Tone Generator and Decoder Circuits
The given project describes how different DTMF tones can be generated using DTMF tone generator chip 91214B and how these tones can be decoded by DTMF decoder chip MT8870 that generates 4-bit digital output.Using these two circuits together one can build DTMF based remote control application in which 91214B chip is used as remote control and MT8870 is used at the receiver side to decode DTMF tones. The 4 bit digital output of MT8870 can be given to micro controller that will control any device or any application as per the button pressed on 91214B based remote control.
How to design a regulated power supply
The performance of each and every electronic system or electronic circuit depends upon the power supply that energizes the circuit or system. It provides required current to the circuit. Any disturbance noise in this power supply can cause problem in working or operation of circuit. If there is any deviation in this power supply level the circuit may not work properly. The accuracy and precision of circuit operation depends upon it. In some of the circuits all the calibration are done at this voltage level. So all these calibrations becomes false if there is fluctuation in supply level. There are two types of power supplies: Unregulated power supply, Regulated power supply. Unregulated supply is used in some circuits where there is no much change in required load current. The load current remains fixed or deviation is very less. Read more to know about this interesting power supply project.
How to increase transmission range by increasing height of Tx antenna
There are two methods to increase transmission range of 434 MHz RF Tx module. 1. Increase applied input power – transmitted power2. Attach an antenna to Tx module In previous article I have explained first method. Please refer previous article of this series. In this session we will see another method. That means we will attach an antenna to Tx and Rx module. Antenna is a special type of transducer, which can convert alternating current in to radio frequency fields and vice versa. Transmitting antenna generates RF fields, and receiving antenna converts RF fields in to alternating current.
PIR Sensor based Alarm
This Passive InfraRed Alarm system (PIR alarm) can switch on a Lamp or Alarm when it detects the heat from an object like moving person. The name PIR (Passive Infrared) is given to the sensor because it receives the infrared rays passively and do not emit any infrared ray. The lamp or alarm remains on few…
Photon-based smart AC socket IoT project
In this project, a smart socket is designed which can be automatically switched using a relay. The socket is interfaced to a Particle Photon based IoT device which keeps track of energy consumption using ACS 712 Current sensor and help automatically disconnect socket connection with the Mains when the power consumption by a device exceeds a threshold value. The Photon also remains connected to a web server via Wi-Fi hotspot and keeps updating the energy consumption data to the server.