Raquel Gallego

Networking and communications

In the exercise abuout communications and networking, I have chossen a laser beam to establish the comunication between 2 microcontrollers.

Using a Serial protocol, the laser beam points to an LDR and sends a character. The transmission is 1/0.02 s = 50 bits per second, with a 20 ms delay between bits= 0.02 seconds.




STEP 1_ Designing the circuit

When there is Light the resistance on the LDR is low , that activates the transistor and the current pass through, means we have a 1.

STEP 2_ Designing the boards

Sender_ We have re-used the Hello motor one and connect the laser beam on the area the DC motor used to be.

We have used a bread board and the arduino to make sure the circuit we have design for the receiver board works.

Cheking the change on the LDR using the oscilloscope.


Based on an analog basic circuit. We know the LDR has a low resistance when there is light and a high resistance when there is not light.



STEP 3_ Code

Based on Neil's code hello bus. We have inverted the code, and desing the electronics to do the inversion.

Sender code, Makefile

Receiver code, Makefile

STEP 4_ Sending the character "U" 1010 1010