Kart

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(Sensors)
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* design and assembly of the chassis and the body
 
* design and assembly of the chassis and the body
 
* analysis of the DC motor
 
* analysis of the DC motor
* [[Kart#FPGA_Design|configuration of the controlling FPGAs]]
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* [[Kart#FPGA_Design|configuration of the controlling FPGA]]
 
* [[Kart#Android_App|completion and extension of the control GUI on the smartphone]]
 
* [[Kart#Android_App|completion and extension of the control GUI on the smartphone]]
  

Revision as of 12:25, 16 August 2022

Contents

The Kart module (214_Pr1) is a Summer School module for students between the 2nd and the 3rd semester. It is a home-made model car remotely controlled by a smartphone.

Demo Kart

The work of the students can be summarized in four main tasks:

Take a look at the karts gallery !

System Architecture

The kart is controlled by a smartphone via Bluetooth.

Hardware

The electronics is composed of a general purpose FPGA daughterboard mounted on a dedicated motherboard with 8 [connectors].

An Honor10 Lite smartphone running Android acts as the interface for the user.

Distributed controls

A Bluetooth - USB dongle on the kart communicates via an UART serial link with the FPGA. The control values are stored in a set of registers accessed through a simple protocol.

The design is separated over four different modules:

Tasks

The programming introduction gives an overview about the structure of the software/hardware and the students' tasks. They comprise:

  • FPGA design for driving the hardware and reading the sensors
  • Android application development for the remote control

The students receive the FPGA board preprogrammed with a functional solution and Android phones with a demo application. This allows to start the development either with the FPGA design or the Android application.

FPGA Design

Design environment

A FPGA design environment is available, based on:


View-pim-tasks.png

For the smoothest experience, you can use Git directly by cloning the repository.

Otherwise, it is possible to download directly the corresponding zip and store it in you personal drive (U:\). While working on the project, it may be preferable to copy it locally for a quicker experience.

Do not forget to either commit and push your modifications to your Git repository or save the modified files on your drive !

Dialog-warning.png

Make sure that there is no space character in the full path to the project files.

HDL may hang while booting or files not loading/saving correctly.

The design is made using HDL Designer as it was the case during the previous semester's labs and project. The FPGAs are configured using the Libero IDE.

Modules designs

Three of the different modules must be completed:

  • The DC motor controller receives a prescaler and a speed value to build the corresponding PWM and direction signals.
  • The stepper motor controller receives a prescaler and the desired angle and builds the coil controls signals.
  • The sensor controller manages I/O comprising hall sensors (to retrieve the driving speed) and a range finder (to get the distance from an obstacle).

Testing

In addition to the tests explained in the different modules, an overall tester is available to test the whole board.

Android App

One goal is to implement an Android application that controls and monitors the kart.

Starting point

  • You can download the Kart project with the minimal interface here: Kart.zip
  • You can find the instructions how to open the project in Android Studio in the programming introduction presentation...
  • The online documentation of all Java classes that are at your disposition is [here]
  • If you need timers, please do not use Java standard Timer and TimerTask, we provide a dedicated Timer class in the package ch.hevs.utils.Timer.
  • To be informed when a sensor has a new value or a register is modified by the kart (i.e. the hall sensor counter value has changed), your application has to implement the KartListener interface. Don't forget to register your listener to the Kart (kart.addKartListener(...)).

Common Problems

  • Don't block the main thread with an infinite loop
  • Don't change the orientation of the display during the execution, it can crash the BT communication. Do it in the Manifest.

Components

Power supply

The main power is drawn from two 6 V / 2400 mAh battery packs in series The motherboard provides two connectors for the batteries, along with an extra one to wire an NiMh charger.

Dialog-warning.png

Make sure to shut the circuit off while charging to avoid higher voltage on the 12V rail.

The charge rate should be of around 0.05C => 120mA here.

The 12V is reduced to a 5V rail through a buck converter.

The daughterboard is then fed with the 5V to provide an extra 3.3V rail.

Finally, an ADC converter provides the battery level as both the battery voltage and consumed current can be read from it.

FPGA board

The daughterboard is equipped with an Igloo AGLN250 FPGA in a VQ100 package. The clock is rooted to the FPGA from a 10 MHz quartz.

It is designed as an SODIMM-200 RAM stick to be easily interchangeable and plugged into various motherboards.

Sensors

The sensors connected to the I/Os of the motherboard are:

Additional Information

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