Background Theory
Presented here is a handheld device that
can be used to measure magnetic field using a Hall effect-based sensor.
The device can be used in the physics lab for conducting various
experiments on magnetism. Moreover, some upgradations can be made to
develop new and advanced devices. The device shows magnetic field in CGS
(centimetre-gram-second system) unit, Guass and is updated every 250
milliseconds on the LCD screen.
Circuit and working
Fig. 1 shows the circuit diagram of Arduino-based Gauss meter. The circuit is built around Arduino Uno board (Board1), MCP3202 12-bit analogue-to-digital (A/D) converter (IC1), WSH315 Hall-effect sensor (IC2) and serial LCD (LCD1).
Fig. 1 shows the circuit diagram of Arduino-based Gauss meter. The circuit is built around Arduino Uno board (Board1), MCP3202 12-bit analogue-to-digital (A/D) converter (IC1), WSH315 Hall-effect sensor (IC2) and serial LCD (LCD1).
MCP3202 (12-bit A/D converter). The
Microchip technology’s MCP3202 is a successive approximation 12-bit A/D
converter with an on-board sample-and-hold circuit. It is programmed to
provide a single pseudo-differential input pair or dual single-ended
inputs. Differential non-linearity (DNL) is specified at ±1 LSB, and
integral non-linearity (INL) is offered in ±1 LSB (MCP3202-B) and ±2 LSB
(MCP3202-C) versions. Communication with the device is done using a
simple serial interface compatible with SPI protocol. The device is
capable of conversion rates of up to 100ksps at 5V and 50ksps at 2.7V.
The MCP3202 device operates over a broad voltage range of 2.7V to 5.5V.
Low-current design permits operation with typical standby and active
currents of only 500nA and 375μA, respectively.
WSH315 (Hall-effect sensor). This ratiometric, linear Hall-effect sensor accurately tracks extremely small changes in magnetic flux density, even those changes that are generally too small to operate Hall-effect switches. The device comes with a Hall-sensing element, linear amplifier and emitter-follower output stage integrated on a single IC to handle small analogue signals.
Arduino Uno board. Arduino is an open source electronics prototyping platform based on flexible, easy-to-use hardware and software. It is intended for artists, designers, hobbyists and anyone else interested in creating interactive objects or environments. Arduino Uno is a board based on ATmega328 microcontroller. It consists of 14 digital input/output pins, six analogue inputs, a USB connection for programming the on-board microcontroller, power jack, an ICSP header and a reset button. It is operated with a 16MHz crystal oscillator and contains everything needed to support the microcontroller. It is very easy to use as the user simply needs to connect it to a computer with a USB cable or power it with an AC-to-DC adaptor or battery to get started. The microcontroller on the board is programmed in Arduino programming language using Arduino development environment. Pins 10 through 13 of Board1 are connected to pins 1, 5, 6 and 7 of 12-bit ADC IC1, respectively. Pin 1 of Board1 is connected to RXD pin 3 of LCD1.
WSH315 (Hall-effect sensor). This ratiometric, linear Hall-effect sensor accurately tracks extremely small changes in magnetic flux density, even those changes that are generally too small to operate Hall-effect switches. The device comes with a Hall-sensing element, linear amplifier and emitter-follower output stage integrated on a single IC to handle small analogue signals.
Arduino Uno board. Arduino is an open source electronics prototyping platform based on flexible, easy-to-use hardware and software. It is intended for artists, designers, hobbyists and anyone else interested in creating interactive objects or environments. Arduino Uno is a board based on ATmega328 microcontroller. It consists of 14 digital input/output pins, six analogue inputs, a USB connection for programming the on-board microcontroller, power jack, an ICSP header and a reset button. It is operated with a 16MHz crystal oscillator and contains everything needed to support the microcontroller. It is very easy to use as the user simply needs to connect it to a computer with a USB cable or power it with an AC-to-DC adaptor or battery to get started. The microcontroller on the board is programmed in Arduino programming language using Arduino development environment. Pins 10 through 13 of Board1 are connected to pins 1, 5, 6 and 7 of 12-bit ADC IC1, respectively. Pin 1 of Board1 is connected to RXD pin 3 of LCD1.
The working of the project is simple.
Hall-effect sensor IC2 has 3 pins: Vcc, Ground and Vout. The Vout of the
sensor is connected to channel 0 (CH0) of ADC IC1 as shown in Fig. 1.
IC1 is connected to Arduino
controller in SPI mode. The sensor generates voltage output from 0.2V
up to 4.8V for 5V power supply. Resolution of ADC IC1 is 5/212 = 1.22mV.
The input voltage to channel 0 of the ADC IC1 gets converted to
equivalent 12-bit binary data and is fetched by Arduino board in two
bytes. Board1 then processes the digital data from IC1 and shows it on
the serial LCD together with the Pole (North/South) indication.
Software
Download Source Code from below link
The software is written in Arduino programming language and the board is programmed using Arduino IDE software. ATmega328 on Arduino Uno board comes pre-burnt with a bootloader that allows you to upload new code without the use of an external hardware programmer. It communicates using the original STK500 protocol. You can also bypass the bootloader and program the microcontroller through the in-circuit serial programming (ICSP) header, but using bootloader, it is quick and easy. Select Arduino Uno from the ‘Tools > Board’ menu (according to the microcontroller on your board) in the Arduino IDE and burn the program through standard USB port in the computer.
** Ask for any Doubt.
