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Marcel Fasterding edited this page Apr 10, 2019 · 7 revisions
  1. Introduction
  2. Requirements
  3. Circuit
  4. Chassis
  5. Mounting
  6. App
  7. Server
  8. Core
  9. Run


The project "Electronic Load Assistance" was developed as a part of the study module "Embedded Systems".

The project should help restricted people to carry heavy loads/objects.

The user only lays down the “load” on the surface of the robot.

Afterwards, the robot can be controlled via the mobile app.

Possible fields of application:

  • Transport of crates or shopping bags
  • Transportation of flowers, potting soil and further supplies which were needed for gardening module


Things you will need to make this project:

  1. Raspberry Pi 3b+ with ssh setup (or similar)
  2. Android/ iOS Smartphone
  3. Smartphone powerbank
  4. 3D printed HC-SR04 mount

Required Lego:

  1. Lego Technic Bricks
  2. Lego Technic Wheels
  3. Lego Technic M-Motor
  4. Lego Technic Servo
  5. Lego Technic Batterybox
  6. Lego Technic electronic connector

Parts needed for the electronic board:

  1. Motor driver L293D
  2. Jumper wire
  3. Male or Female connector for jumper wire
  4. 330 Ω resistor
  5. 470 Ω resistor
  6. Buttons
  7. HC-SR04


This is the electrical diagram for the project. This circuit shows the motor controller, the ultrasonic circuit,

the emergency stop switch and the pinout for the lego connector.

electrical diagram


This is the raw chassis of the robot.

Everything is build with lego technic bricks.

The servo and motor are also from lego technic.

raw chassis

  • The green bricks in the left and right of the picture are bumpers.
  • The robot will stop driving if it hits an object

This is the robot finished.

Chassis Top

Chassis Front

Chassis Rear


This is the 3D printed mounting of the HC-SR04 ultrasonic sensor.

It was created by the user JakobTheEmperor on Dec 10, 2018.

For this project we need four of them.

You can find the file on Thingiverse

HC-SR04 mount

HC-SR04 mount

HC-SR04 mount


The app is created with the Ionic framework.

With the app you can control the robot.

Please follow this description to setup the app.


The server is running on the Raspberry Pi 3b+.

At the current state, the server stores the control commands,

which were send by the smartphone app.

Please follow this description to setup the server.


The core modul is also running on the Raspberry Pi.

This modul handles the communication with the hardware and

controls them with the stored commands from the server.

Please follow this description to setup the core modul.


  1. Be sure that the server, the core module and the app are running.

  2. This is a screenshot of the android app

    Android App

    • The blue buttons are for the movement of the robot
    • The two red buttons stopping the robot
    • If the robot collides with an object, you have to press one of the red buttons first.

    After that you can control the robot again.

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