What it shows
A tilt sensor on a glove tells the car which way to go. The data is sent over a 2.4 GHz radio link by a pair of modules, so the car follows hand movements without a phone.
The science
The MPU6050 accelerometer measures the component of gravity along each axis, which gives tilt: forward tilt means drive forward, back tilt means reverse and left or right tilt means turn. The glove sketch packs two tilt values into a small structure and sends it by the nRF24L01. The car receiver reads the structure and sets the speeds of the left and right motors. A dead zone of about 10 degrees keeps the car still when the hand is level.
Materials
Cost: under Rs 1,500. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- Two Arduino Nano boards
- An MPU6050 sensor module
- Two nRF24L01 radio modules with two 10 µF capacitors (across 3.3 V and GND at each module)
- An L298N motor driver and a 2WD car chassis
- A 9 V battery for the glove and a 7.4 V pack for the car
- A glove or a velcro strap and wires
Safety
For this project: The nRF24L01 runs from 3.3 V only, not 5 V. Charge lithium cells only with a proper charger and an adult. Test the car on a stand first and keep fingers off the wheels.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Fix the MPU6050 on the back of the glove and connect it to the glove Nano: VCC to 5 V, GND to GND, SDA to A4 and SCL to A5.
Connect the nRF24L01 to the 3.3 V pin, GND and the SPI pins (CE to 9, CSN to 10, SCK to 13, MOSI to 11, MISO to 12) with a 10 µF capacitor across its power.
Install the RF24 library and run the GettingStarted example on both Nanos to check the radio link.
In the glove sketch, read acceleration, convert to tilt angles and put them in a struct.
Send the struct every 20 ms with radio.write.
Connect the car Nano to the second nRF24L01 and the L298N, and read the struct in the car sketch.
Map forward and sideways tilts to the speed of the left and right motors, with a dead zone of 10 degrees.
Add a failsafe that stops the car if no message arrives for half a second.
What you should see
The car goes forward, back, left and right as the hand tilts and stops when no data arrives.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1How does the accelerometer measure tilt?
It senses how gravity divides between its three axes.
2Why add a 10 µF capacitor to the radio?
It supplies short current pulses and stops the radio from resetting.
3What is a failsafe?
A program rule that stops the car if the signal is lost.
4Why is a dead zone used?
So small shakes of the hand do not move the car.
Take it further
Add a flex sensor on one finger to control a horn or a speed boost.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
Robotics
Build a Bluetooth-Controlled Car
Drive a robot car from a phone with an HC-05 module and Arduino
Robotics
Robotics and Electronics Basics Study Book
The complete study notes, practice questions and glossary for Robotics and Electronics Basics