Drakkar (Line Follower Car)
Drakkar is a line follower car compatible with the Allmycircuits software and mightyBug-A boards. The chassis is 3d-printed, hence it is highly customizable and multiple versions of the car were tested. This car competed in the Oshwdem 2018 achiving the overall 2nd place.
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The car was built using a 3D-printed chassis and DC Pololu motors (30K rpm) with 1:10 gear reduction.
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Most board components are through-hole with very easy soldering.
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The weight of the car (including Lipo batteries) is of 112-118 grams, depending if headers are used or if the components are directly soldered to the board.
The board is the mightyBug-A v1.1. board. You can find the kicad project here LINK.
| Item | Description | Quantity |
|---|---|---|
| Bluepill | STM32F103 microcontroller board | 1 |
| MP2307DN | 3.3V Step-down voltage regulator. Can be found with the name Mini-360 in chinese stores. | 1 |
| U3V12F9 | 9V Step-up regulator board from Pololu | 1 |
| Buzzer | Passive buzzer board | 1 |
| TB6612FNG | 2 Channel motor driver board | 1 |
| 5 mm LED | 5mm LEDs of different colors | 2 |
| Push button | Through hole push buttons | 3 |
| 100Ω Resistor | Through hole resistors | 5 |
| 47kΩ Resistor | Through hole resistors | 1 |
| 20kΩ Resistor | Through hole resistors | 1 |
| 40x1 Female socket 2.54mm pitch | Female socket to plug, the bluepill, the motor driver and the Bluetooth module to the board | 1 |
| 40x1 Male pin 2.54mm pitch | Male pin strip to plug the motors, the battery, the expansion boards and the jumper to the board | 1 |
| 40x1 Right angle male pin 2.54mm pitch | Male pin strip to connect the reflectance sensor array to the board | 1 |
| 33uF Capacitor | Electrolytic capacitor to connect to the output of the step up regulator | 1 |
The chassis is a 3D printed dragster-like car. Many chassis were tested (of different length). The one used in the competition was the "short snout" version (in the left of the image). Download the chassis from here LINK
DC motors were attached to the chassis using these motor-supporters and some clamps. 
Note: Be careful with putting pressure on the motor gears whilst tying the motor with the clamps or you can greatly alter the behaviour of the motors and limit appreciably its lifespan.
You can find all the chassis and motor supporters here LINK
Drakkar used in competitions Scaleauto Supersoft foam wheels (25mm diameter). Additives were used to improve the efficiency of the wheels (we tested several strong-grip for wood tracks with similar performance).
Drakkar compited in the Oshwdem 2018 with the code of the following commit: LINK
Latest software is compatible with all mightybug-A boards, including the one used by Drakkar. It contains improvements and bug corrections. Thus, we highly recommend using the latest software version for this car.