MultiDimension Technology Co., Ltd.

Page 2 of 5

Web: www.dowaytech.com/en, Email: info@dowaytech.com

MDT USB25103

No.7 Guangdong Road, Zhangjiagang Free Trade Zone, Jiangsu, 215634, P.R. China

Ver. 1.0a

Hardware Description

The USB magnetometer includes three orthogonal magnetic field sensors located within 3 mm from

the probe tip and covered with an aluminum tube.

The probe is connected to USB data acquisition

hardware by a 1 m long cable.

The probe has the following configuration.

The USB magnetometer hardware is compatible with the popular open source Arduino UNO board,

and thus with the Arduino programming environment or Atmel microcontroller development tools.

The user may develop custom firmware at his/her risk.

The hardware includes a boot loader for

uploading Arduino code.

The USB magnetometer hardware model is defined as follows:

The magnetic sensors are used to detect a magnetic field, which is converted to a proportional

voltage value.

The magnetic sensors are biased by a temperature compensated voltage reference.

The magnetic sensor outputs are connected to ADCs which digitally sample the voltages and sends

the digital signals via a 1 m long cable to a microcontroller over an I2C bus.

The microcontroller

converts the sampled sensor voltages to a magnetic field values using calibration coefficients stored

within an EEPROM.

These EEPROM values may be overwritten by the user.

The

microcontroller then sends the computed magnetic field values to a serial bus, which is connected to

a FTDI231X Serial-to-USB convertor.

The I/O of the FTDI231X Serial-to-USB convertor is a

standard USB 2.0 port.

A driver on the computer or other computing device is used to create a

virtual COM port, which is then accessed by the MDT USB magnetometer GUI, a terminal

emulator program, or other custom written program.