# Building Instructions

Finished Amsel prototype

Amsel wiring

Difficulty: medium | Time: 60 minutes



# Overview

Development and conception of a self-construction kit for a robot for the teaching of programming basics in the 1st semester Information System of the Information Science programme.
The robot is remote controlled via an interface (web or mobile application). The students program the robot's movements themselves and learn how to use Python. Depending on the use case, the robot can be extended, for example with a pen for Turtle Graphics. The robot should stand upright and should have a display and, if necessary, LEDs to appeal to the students to increase acceptance.
This building instruction helps the students to build the robot by themselves.

# Tools & Materials

Tools Materials
Soldering Iron 1x 3D printed Amsel Chassis + Cover
Screwdriver 2x 3V - 6V 2 axis TT Motor + Wheels
Pliers 1x L298 Dual H-Bridge
Sticky Tape 1x Powerbank 5V-OUT/Battery-Case
3D Printer 1x USB Charging Cable
1x 0,96 inch OLED I2C Display
1x HC-SR04 Ultrasonic Sensor
1x ESP8266 microcontroller
1x free spinning wheel
1x On/Off Switch
2x Screws + Nuts (M4x35)
Many Jumper Wires

TIP

See the hardware page for reference what materials we used.

# Necessary preparatory work


Before you can start assembling the robot, there are some necessary preparations to be done:

  1. Charge the powerbank, so you're able to test the robot after assembly.
  2. The chassis as well as the lid should already have been printed with the 3D printer.
  3. Solder a cable to each of the two contacts of the DC motors, if not already existing.
  4. Cut off a 20cm piece of the USB charging cable, starting from the USB connector. The piece should now be stripped at least halfway to expose the wires inside. Only the red and black wires are needed, depending on the USB cable.

# Assemble the robot


Amsel assembly: Overview materials


# 1. Ultrasonic sensor

First you put the chassis of the robot in front of you. The first part to be installed is the ultrasonic sensor, which is located at the front of the chassis. Before you can insert it into the chassis, connect a cable to each of the four connectors of the sensor. Then carefully insert the sensor into the chassis via the guide rails provided and place it in the holes provided.

Put the chassis of the robot in front of you

Connect a cable to each of the four connectors

Carefully insert the sensor


# 2. DC Motors

Next, take the two DC motors and place them on the chassis with the contacts facing outwards. Then you can fix the motors to the chassis with the corresponding nuts and bolts. Once the motors are attached to the chassis, you can plug the two wheels into the motors.

Take the motors and place them on the chassis

Fix the motors to the chassis


# 3. Back wheel

Take the freely rotating wheel and stick double-sided adhesive tape on the underside of the wheel. The wheel can then be attached to the chassis.

Attach the backwheel to the chassis


# 4. Powerbank

Afterwards take the loaded powerbank and place it in the recess provided in the chassis.


# 5. ESP8266

Then take the ESP8266 microcontroller and plug it into the breadboard.

Attention

There should be at least one free row on the breadboard to plug in cables. If not, the breadboard must be cut in half.

The other components of the robot, such as the OLED display, the H-bridge and the ultrasonic sensor already in the chassis, are wired as follows:

Display wiring

H-Bridge wiring

Sensor wiring

Display ESP8266
GND GND
VCC 3V3
SDA D2
SCL D1
H-Bridge ESP8266
GND GND
12V VIN
ENA D0
IN1 D8
IN2 D7
IN3 D6
IN4 D5
ENB D3
Sensor H-Bridge ESP8266
GND GND
VCC 12V
Trig RX
Echo D4

# 6. Switch (optional)

After everything is wired up, take the lid of the robot and stick the OLED display from below with adhesive tape in the provided recess. Then place the switch on the lid. The switch must now be connected to the H-bridge and the USB charging cable (in this case the battery) as follows:

Switch wiring


# 7. Placing the wired components

As a last step, place all components in the designated places in the chassis and fix the lid on the robot.

TIP

Wire handling
To arrange the cables a little bit better it can be useful to bundle them with some tape and glue them to the inner wall of the chassis.

After that you only have to connect the cables of the motors to the H-bridge. Then you can transfer the firmware to the robot via USB on the ESP8266.

Attention

When flashing the robot, never connect it to the power supply, otherwise it may cause a short circuit and destroy individual components of the robot.

After that, the robot is ready for use.

Place all components in the designated places

Close the wired lid

It can be useful to bundle cables