First I ordered many different components through Conrad, such as:
- An alphanumeric segment display Red. This is a 16 segment display. I opted for a16 segment display instead of a 7 segment display so that I can project then slash of N (neutral) and R (reverse).
- An Arduino Nano (this converts the signals from sensors into output signals to the screen).
- 2 TT Electronic spot meters of 10 kohm for measuring the gear position.
- A plastic nutrition box.
- And other components such as resistors, transistors, voltage regulators, capacitors, etc.
Then I started drawing the housing box in SolidWorks in which the LED screen had to be placed. I immediately signed a support to this housingbox with which the whole could be attached to an existing support in the rallycar. The microcomputer (Arduino) is immediately attached to the cupboard behind the LED screen.
I was able to print the entire box 3D through my school education, so I could also choose the black material that this printerused.
Here are two more photos of the print and how the screen is attached, this whole is then placed in the 3D-printed box.
The electric circuit:
After the screen was ready I started installingthe sensors on the gear lever. I also drew this whole out on SolidWorks. Theoperation works as follows:
By using 2 potentiometers I candetermine the position of the two arms (gear lever fingers). This position is then converted into signals for the segments of the LED screen by means of the Arduino.
After designing the sensor setup, I started testing the operation by determining the position with the sensors. I was the first to make an arrangement of cardboard, with a pen refill I simulate the gear lever.
In the Arduino program I measure the positions of the gears on by one for example gear 2:
//Gear 2
if((sensorValue1 >582) &&(sensorValue2 > 542)){digitalWrite(2, LOW);digitalWrite(3, HIGH);digitalWrite(4, LOW);digitalWrite(7, HIGH);digitalWrite(8, LOW);
digitalWrite(9, LOW);digitalWrite(10, LOW);digitalWrite(11, HIGH);digitalWrite(12, HIGH);digitalWrite(13, HIGH);}
Explanation: If potentiometer 1 is at the bottom left (Above 582) andpotentiometer 2 (Above 542), 5 segments light up (3, 7, 11, 12, 13).
Then I printed a solidWorks mounting plate from paper and kept it to see if it came with the sensors at the gear lever.
When that was right, I made a steel version and the two take-away fingers from aluminum. I assembled this whole. Finally, the steel plate still needs to be rounded and sprayed to prevent rust.
Then replace the shield and ready. The only thing that still needs to be done is to properly attach the dust cover.
Finally, I made a power box. This contains:
- A 9 Volt battery, this is an independent power supply without the car, I did this to exclude malfunctions in the car's electrical system.
- A relay to enable the screen to turn on automatically.
- A voltage regulator to convert 9 volts to 5 volts.
- A 3-position switch (Auto / Off / On).
Content of the power box:
The circuit:
Here you can see how the box is placed in the car:
A photo of the end result:
The support to which the screen is mounted had been in the car for along time, because our action camera was mounted on this. The screen is lowenough so that the camera also has enough space.
A couple of weeks ago we drove the Hellendoornrally, the screen successfully reached the first rally. I am very satisfiedwith the end result, and hope that the screen will last for a long time.
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