Introduction: Tin Box Phone-Controlled RC Car
I've been looking for a good way to take away boredom when I have nothing to do. So I came up with this pocket sized tin box RC car to take away the boredom out of everything!
It has all the great characteristics! It's small, lightweight, easy to make, easy to control, and very portable!
It really isn't hard to make, all you need are simple electronics like an Arduino Nano and simple materials like a tin box.
It isn't hard to control either, all you need to do is open an app on your phone and enjoy!
In this Instructable, I'll walk you through the step by step process of placing an RC circuit into a tin box.
Step 1: Tools and Materials
For the electronics, all you will need are:
- Arduino Nano
- HC-05 Bluetooth Module
- Continuous rotation 9g Servos
- Servo arms
- 9 volt Battery
- 9V battery clip
- 5 Volt Regulator
- necessary amount of wires
- Android Phone (controller)
For the chassis, you will need the following materials:
- Tin box
- Two bottle caps
- Rubber bands
- four small nuts and bolts
And finally for the tools, you need:
- Something to cut the tin (I used a rotary tool)
- Soldering Iron and lead
Step 2: Preparing the Chassis
The main chassis for this car will be the tin box. It provides enough protection for the delicate electronics.
The first thing to do is to place the servos inside the tin box and mark the parts where the servo cylinders touch. Once you have marked these areas, you can now proceed to cutting the outline. (make sure to avoid cutting the hinges) I used a Dremel rotary tool to cut this part. The cut chassis should now look like the picture above.
Test fit the servos to make sure the holes are big enough. The holes allow easy access from the servos to the wheels.
Step 3: Modifying the Servos
Since I didn't have continuous rotation servos, I modified the potentiometer, gears, and circuit board of the servo. All I did was add two 2.2kΩ resistors and cut some parts of the gears in order to get continuous clockwise and counter-clockwise rotation from the servos.
To learn more about modifying 180° servos, visit this instructable: https://www.instructables.com/id/How-to-Modify-a-Micro-Servo-Motor-SG90-for-Continu/
Step 4: Wiring and Soldering Everything Together
Let's move on to the electronics!
All you have to do is follow the wiring diagram in the schematic above that I made in fritzing. Cut the wires of the servos to avoid wire clutter. All of the ground or black wires are connected together. The bluetooth module will be using the arduino's 5 volts while the servos will be taking power from the regulator. Make sure that the tx and rx of the arduino is connected to the rx and tx of the bluetooth module, respectively. Also, check the datasheet of your regulator for the pin layout. Mine happens to be In-Ground-Out. The right servo will be attached to digital pin 4 while the left servo will be attached to digital pin 5.
I soldered everything onto the Arduino Nano to save time and to avoid disconnection. Be sure that the wires are soldered properly to avoid it being disconnected due to vibration. Heatshrink or tape any exposed terminals or wires to avoid short-circuit. If you want to, you could insulate the inside of the tin box with electric tape.
Step 5: Sticking Everything Into the Tin Box
It's time to bring the chassis ang electronics together!
Grab some foam tape and cut the appropriate sizes for each and every part. Tape everything into the box as shown in the picture above. Make sure that you prevent any terminal from sticking to the tin box.
Once you have taped everything together, fold the wires into the box and try closing the tin box. If it doesn't close, there's probably something in the way of the lid.
Step 6: Making the Wheels
I chose these metal bottle caps because they had grooves where I could tie rubber bands. But any cap would do fine.
First thing to do is to drill bigger holes into the servo arms then line them up to the center of the bottle caps. Drill a hole in the cap directly aligned to the holes in the servo arm. Once you've drilled holes on both arms and caps, screw them together with the small nuts and bolts. Lastly, tie rubber unto the caps to provide extra grip.
The finished wheels should look like the ones in the picture above.
Step 7: Uploading the Code
The hardware's done! All that's left to do is to upload the code!
Open Arduino IDE (download it here) and open "the code". Connect the Arduino Nano to your computer and go to Sketch>Upload. This code takes the bluetooth signals given off by the phone and translates those signals into motor actions.
Step 8: Preparing Your Phone
Grab your phone and install the "Arduino Bluetooth RC car" app. This app controls the car via bluetooth. Go to your phone settings and switch on bluetooth. Find and connect to the device named "HC-05". the password is usually 1234. Once you are connected, open the Arduino Bluetooth RC car app and tap the gear icon and select "connect to car". Select the HC-05 to establish a connection between the app and the car. The red circle in the upper left corner should now turn green.
That's it! You're done!
Step 9: Play!
Enjoy your pocket-sized tin box rc car! Its easy to bring anywhere. Just take the wheels off and slip the box and wheels into your pocket. Take it out whenever you're bored or tired. It'll surely cheer you up!
I hope you find my first instructable easy and helpful!