Colin

Raspberry Beret

This is a cape for the Raspberry Pi that contains helpful inputs for robotic systems control. It has a dual H-Bridge motor driver, dual encoder readers, and a 10-bit ADC.

Used Pins

• ADC (SPI0):

   CS=26
   DI=19 (MOSI)
   DO=21 (MISO)
   SCK=23

The ADC can easily be controlled using the Adafuit MCP3008 library. https://learn.adafruit.com/raspberry-pi-analog-to-digital-converters/mcp3008.

To use this library, enable SPI using sudo raspi-config.

Then, in the python code provided by Adafruit, comment out the "Software SPI Configuration" and enable "Hardware SPI Configuration" with the pins specified above.

• H-Bridge:

   IN_LOW1=16
   IN_LOW2=15
   IN_LOW3=13
   IN_LOW4=11
   PWM_LOW_A=33
   PWM_LOW_B=12

• Encoder Readers (SPI1):

   MOSI=38
   MISO=35
   SCK=40
   CS1=36
   CS2=37

To enable SP1, go to /boot/config.txt and add

   dtoverlay=spi1-2cs,cs0_pin=16,cs1_pin=26

This enables SPI1 with 2CS pins, and selects GPIO pins 16 and 26 as the CS pins.

To enable SPI0, just

   sudo raspi-config 

go to interfacing and enable SPI.

Sample Code

ADC

Code for ADC at http://raspberrypi-aa.github.io/session3/spi.html

Motor Driver

Code for the motor driver:

   import RPi.GPIO as GPIO
   import time
   from time import sleep
   
   GPIO.setmode(GPIO.BOARD)
   
   // setup BBB GPIO pins
   
   GPIO.setup(12, GPIO.OUT)
   GPIO.setup(33, GPIO.OUT)
   GPIO.setup(16, GPIO.OUT)
   GPIO.setup(15, GPIO.OUT)
   GPIO.setup(13, GPIO.OUT)
   GPIO.setup(11, GPIO.OUT)
   
   pwm1 = GPIO.PWM(33, 1000)
   pwm2 = GPIO.PWM(12, 1000)
   
   GPIO.output(16, GPIO.LOW)
   time.sleep(4)
   
   // TURN LEFT
   
   def Left():
       GPIO.output(11, GPIO.HIGH)
       GPIO.output(13, GPIO.LOW)
       GPIO.output(15, GPIO.LOW)
       GPIO.output(16, GPIO.HIGH)
       pwm1.start(90)
       pwm2.start(90)
   
   // GO BACK
   
   def Back():
       GPIO.output(11, GPIO.LOW)
       GPIO.output(13, GPIO.HIGH)
       GPIO.output(15, GPIO.LOW)
       GPIO.output(16, GPIO.HIGH)
       pwm1.start(90)
       pwm2.start(90)
   
   def Forward():
       GPIO.output(11, GPIO.HIGH)
       GPIO.output(13, GPIO.LOW)
       GPIO.output(16, GPIO.LOW)
       GPIO.output(15, GPIO.HIGH)
       pwm1.start(90)
       pwm2.start(90)
   
   print "running"
   Left()
   time.sleep(4)
   Back()
   time.sleep(4)
   Forward()
   time.sleep(4)
   pwm1.stop(pwm1)
   pwm2.stop(pwm2)
   GPIO.cleanup()

Encoder Reader

Encoder readers code can be found below in the robot code section

Analog Sound Board

The analog sound board, designed by Mauricio de Oliveira with PCB layout by Colin Zyskowski, consists of a preamp

with AC- or DC-coupled outputs, a signal summer and subtractor, an envelope detector, and a threshold detector. The center of the board contains a patching

section that allows any stage of the board to be routed to any other. The purpose of the board is to perform analog signal analysis and

to easily interface with digital micro-controllers.

• Schematics

Preamp:

Envelope Detector:

1. • PCB

1. • Documentation

Robot Code

1. Robot Code
   • As of 03/16/16

The following code is the present state of programming for the sound-detecting robots.

The code consists of two main parts right now - a server and a client. The robot runs the

client code that sends information regarding it's position and physical/sonic environment

to the server. The server then creates a graphic map of that robot's environment. The

third bit of code is the module for the HMC5883l magnetometer that is being incorporated

into the odometry system for the robot. So far, everything runs in Python on a Beaglebone Black.

1. File:Robut1.py

2. File:Robot server3.py

3. File:Magnet.py