week 13

for this assignment i will design a board that will measure magnetic fields using a hall effector sensor, it will transmit the intensity of the magnetic field trough a serial port then we could read the value in a computer via the usb to RS232 adapter or in a smartphone via bluetooth using the bluetooth to serial adapter as usual i will design the board in eagle as i did in the week 6 assigment

i will program the microcontroller using arduino as i did in the week 8 assignment embedded programing review the week 8 programming clicking here

to write the program of the board we will use the pinout image that will tell us the name of the port of each pin

we will check the board to know which pins are used for what and asign the good port name in the program

now that we know the name of the ports that we use we can write the program in arduino

you can download the sch eagle file clicking here

Measure something: add a sensor to a micro-controller board and read it

you can review the week 6 assigment clicking here

first we have to read the hall effect sensor data sheet to know how to connect it to the microcontroller

we can see in page 2 the connections pins that we will use to connect the sensor to the micro-controller

A Hall effect sensor is a transducer that varies its output voltage in response to a magnetic field.

Polarity The symbol “B” is used for flux density. Hall sensors use the convention that magnetic fields traveling from the bottom of the device through the top are “positive B”, and fields traveling from the top to the bottom of the device are “negative B”.

analog Hall sensors have an analog voltage output that changes proportionally with the magnetic field. When no magnet is present (B = 0), the output voltage is VQ (typically 1V). The presence of a magnetic field scales the output toward 2V or 0V.

week thirteen

input devices

now we can design the circuit schematic

and with the schematic we can now design the pcb

we make the board in the modela mill, solder and program the micro controller

this is a video of the test that i did i connect the board via the bluethoot module and bluetooth terminal in andoid

you can download the board eagle files clicking here

you can download the arduino program clicking here

Carlos Pérez Ramírez