Robots with Wheels

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Introduction

 

This is my entry into the Robots On Wheels Project14 contest. The PWHBot will be designed to self navigate an area and report its location as well as environmental conditions back to a central node using MQTT. The main brains of the Bot is a TI4C123GXL launchpad that is programmed in bot Assembly and C code. This thus far controls the motor direction as well as the Ultrasonic Sensor (Ping Sensor) located on the front of the bot. IR sensors will be added to enhance the obstacle avoidance capabilities of the bot and a GPS device will be added to collect the bots location. A CC3100(or perhaps CC3120) booster pack will be added for WiFi connectivity which may require a separate board to control such as a MSP432 or MSP430FR5969. I currently have a Pine64 running the Mosquito MQTT Broker as well as Inductive Automation Ignition Edge and intend to use this to keep track of the Bots location and data.

I'll use some GearTie rubber coated wire bendable ties to mount the IR sensors. This will allow some freedom to move the sensors in a different location when needed.

 

So, what is with the PWHBot name, well the chassis I am using is a Pee-Wee Runt Rover chassis from Actobotics, and borrowing from the name I decided to name the bot PWHBot, or Pee-Wee Herman Bot.  I was going to go with Conky, but I did not want to build a standing bot at this time.  The typewriter head seems cool though.

 

Hardware:

  • TM4C123GXL
  • CC3100 WiFi Booster Pack (MQTT data processing)
  • Parallax 28015 Ultrasonic Sensor
  • Actobotics Peewee Runt Rover
  • Adafruit TB6612 H-Bridge
  • Adafruit Ultimate GPS Breakout fw5632

 

 

Voltage Regulators

    • LM1086 – 3.3v Regulator
    • LM7805 – 5.5v Regulator
    • 10 uF Cap
    • 100 uF Cap
    • 2 x 10 uF cap Tantalum

 

 

IR Sensors

    • LM339 Quad Differential Comparator
    • 4 x IR LED
    • 4 x Photo Transistor
    • 4 x 10K Potentiometer
    • 4 x 100 Ohm Resistor
    • 8 x 10K Ohm Resistor

 

        MQTT Server

    • Pine64 Running Ubuntu Mate
    • Mosquito MQTT Broker
    • Inductive Automation Ignition Edge
    • Webserver

 

I've been struggling a bit with making videos since I gave up my MacBook Pro to my daughter since her's died.  I'm trying to use Windows and have found a pretty cool Video Recording tool that allows me to add multiple screens together and create shortcuts for things like starting and stopping the videos as well as bring in other windows when needed. The issue I run into is that the camera I am using, a Logitech c920 blanks out sometimes and yesterday for some reason the audio stopped. I ended up having to delete the build in recording device on the system to get the audio back.  Mac are just much more easier to use.

The software I am using is OBS Studio (Open Broadcaster Software) and did have a bit of a learning curve.  Thus far it seems to work nicely when it does work.

https://obsproject.com/

 

Here be some pics of the PWHBot in progress and a video listed at the end which was recorded from the Logittech Webcam Software tool.

 

View of the Chassis with Tm4c123GXL and custom perf board installed. I created a board so the Lanchpad could plugin rather than just hang off the end and then added the Adafruit TB6612 H-Bridge along with 3.3v and 5v regulators to step down the 7.2v that is coming from 2 -3.7v Li-Ion batteries. This supplies 3.3v to the Launchpad and 5v for the motors, Ping sensor and IR sensors.

 

PWHBot side view with TM4C123GXL and custom board for H-Bridge

 

Front view of PWHBot showing Ping sensor and IR Sensor arms.

PWHBot Front view showing Ping sensor and IR sensor arms

 

Close up of Adafruit TB6612 H-Bridge mount on custom board as well as voltage regulators and added headers for connectivity.

 

PWHBot close of up Adafruit TB6612 H-Bridge mount on custom board

 

IR Sensor board using a LM339 Quad Comparator  DIP

 

PWHBot IR Sensor board using a LM339

 

Close up of IR Sensor board

 

PWHBot Close up of IR Sensor board

 

Close up of IR Sensor using a Infrared LED and a Phototransistor wrapped in Shrink tubing

 

PWHBot Close up of IR sensor

 

 

Video showing the PWHBot running stationary

 

That is it for now.  I hope to add more content as I progress with this build.