Networking and communications

https://academy.cba.mit.edu/classes/networking_communications/index.html

💡Group assignment

Send a message between two projects
Document your work to the group work page and reflect on your individual page what you learned

About this week

Briefly describe the goal of the assignment. What are you characterizing, testing, or exploring

For this week we are sending a input from one project over TXRX to another project

The input device is Carls linear pot module for a FabXiao.

Tools and materials used

List all the machines, software and materials used in this assigment.

Thonny
Fab Xiao (RP2040)
Thoms Dev board (RP Pico)
Circuit Python

Process and methodology

Describe step-by-step what the group did. Include sketches, screenshots, or videos if possible.

Transmision:

For the transmitting board we used the following code in CircuitPython to send a UART over the TX and TX pins on our devices.

import board
import busio
import digitalio
import analogio
import time

# Set up UART on TX=GD6, RX=D7 (we only use TX here)
uart = busio.UART(tx=board.TX, rx=board.RX, baudrate=9600)

# Set up a pot on analog pin A0
pot = analogio.AnalogIn(board.A0)

center = 65535/2 # The center of the pot
neutral_zone = 10000 # Area on pot where there is no input

while True:
    
    pot_value = pot.value
    deviation = pot_value - center

    print(pot_value)

    if abs(deviation) > neutral_zone: 
        
        if deviation > 0:
            uart.write(b'PRESSED\n')
            print("Sent: PRESSED")
    time.sleep(1)

Receive

import board
import busio
import digitalio
import time

Set up UART on TX=GP4, RX=GP5 (we only use RX here)
uart = busio.UART(tx=board.TX, rx=board.RX, baudrate=9600)

Set up onboard LED (or use another GPIO pin)
led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

buffer = b''

while True:
    data = uart.read(32)  # Read up to 32 bytes at once
    led.value = not led.value  # toggle LED

if data:
    buffer += data
    if b'\n' in buffer:
        line, _, buffer = buffer.partition(b'\n')
        message = line.strip().decode("utf-8")
        print("Received:", message)
        if message == "PRESSED":
            led.value = not led.value  # toggle LED

Diarmuid had to modify the Board to access the Tx and Rx pins with some form of header - this required some stealthy soldering skills that we all lack but got there!! It is not the prettiest but it will get the job done!!

We connected the two boards together after attaching a header to Diarmuid's Fab board for Tx and Rx.

Attempted to run the code - something was not working!!

The header on Carls Tx pin was going to ground - to fix this carl just held the cable to the Tx pin on the XIAO RP2040- and we also had to run a cable from ground to ground on each board.

and hey presto - we are networking - sending and receving data.

Group conclusions

Findings: Did not receive as many messages as we sent, must be due to poor connection / noise

Challenges: the development boards we are using have other components on the TXRX pins so we had to get creative as to our connections

Solutions: we ended up probing with jumpers by hand.

Type here

Files

Add all files created for this group assignment

See below link to to files created this week:

PreviousOutput devices NextMechanical and machine design

Last updated 1 month ago

import board import busio import digitalio import analogio import time # Set up UART on TX=GD6, RX=D7 (we only use TX here) uart = busio.UART(tx=board.TX, rx=board.RX, baudrate=9600) # Set up a pot on analog pin A0 pot = analogio.AnalogIn(board.A0) center = 65535/2 # The center of the pot neutral_zone = 10000 # Area on pot where there is no input while True: pot_value = pot.value deviation = pot_value - center print(pot_value) if abs(deviation) > neutral_zone: if deviation > 0: uart.write(b'PRESSED\n') print("Sent: PRESSED") time.sleep(1)

import board import busio import digitalio import time Set up UART on TX=GP4, RX=GP5 (we only use RX here) uart = busio.UART(tx=board.TX, rx=board.RX, baudrate=9600) Set up onboard LED (or use another GPIO pin) led = digitalio.DigitalInOut(board.LED) led.direction = digitalio.Direction.OUTPUT buffer = b'' while True: data = uart.read(32) # Read up to 32 bytes at once led.value = not led.value # toggle LED if data: buffer += data if b'\n' in buffer: line, _, buffer = buffer.partition(b'\n') message = line.strip().decode("utf-8") print("Received:", message) if message == "PRESSED": led.value = not led.value # toggle LED