Summary of RC Car Anti-Crash System Using Arduino
This article details a student project modifying a $20 RC car with an Arduino Leonardo to create an anti-crash system. The author uses an infrared proximity sensor to detect obstacles and automatically trigger the car's brakes when it gets too close to a wall, demonstrating digital logic control of DC motors via H-Bridges.
Parts used in the RC Car Anti-Crash System:
- Arduino Leonardo
- Mini-USB cable
- Computer with Arduino programs
- Inexpensive Remote Controlled Car
- Sharp Distance Sensor 2D120X
- SN754410 H-Bridge
- Heat Sink for SN754410
- Oscilloscope or Multimeter
- Breadboard
- Perfboard
- Solder and Solder Gun
- Hot glue gun
- 9v Batteries
- AA Batteries
- Wire Cutters and Strippers
Hi guys! So for my electronics class this year we were tasked with creating some kind of electronic gadget in order to demonstrate what we learned over the semester. Being a car-loving type of guy, I decided to get a cheap RC car and see in what ways I could hack it using an Arduino Leonardo I had leftover from lab. Having an infrared proximity sensor handy, I thought It would be nice to use the sensor to brake the car whenever It got too close to crashing into a wall. I’ll try to be as clear as possible in case you guys want to build something similar or in case it’ll help with one of your projects.
Step 2: The RC Car
First off, I needed to get an inexpensive RC car I could hack. I didn’t want to get an expensive RC car in case I ended up ruining it over the course of my project so I ended up get this ~$20 car off of Amazon. Overall, there were no big surprises with this little car. The car required 4 AA batteries while the remote control it came with required a 9v battery, sadly the batteries were not included. Anyways, the next step was to open up the car and see what I was dealing with.
Step 3: Opening it Up
The Basics:
The car opened up without too much trouble, it just had a couple of screws on the bottom. Not knowing what to really to expect, I was kind of surprised to see how straightforward a setup the car actually employed. Essentially there are three main parts; the circuit board, the rear wheel drive DC motor, and the DC motor used for turning. I’ll discuss these in more detail in the next step.
The Remote Control:
I also opened up the remote control in order to see what type of input the car would be expecting. It also had a relatively simple set up, each control was basically dependent on two switches. For example, in order to control direction you’d press the switch corresponding to desired direction.
Since the car did not have variable speed or direction, I concluded that the car most likely dealt with digital logic. In other words, I was expecting to see the voltages used to either go HIGH or LOW.
Step 4: Analyzing the Insides
The Receiver:
Once I got the car opened I tried to work out how the DC motors were being controlled. I decided to look up the chip placed in the middle of the circuit board to see exactly what it did. I discovered that it’s a receiver chip with four pins used to control both direction and speed. Flipping the circuit board over, I saw the pair of H-Bridges used to drive the DC Motors.They basically provide enough current to make sure the motors run. I’ll talk about H-Bridges a bit more later.
The Motors:
Looking at the circuit board closely, I saw that it had a power and ground connection going to the battery pack. The other connections went to the motors. Each motor was connected to the circuit board by two wires (one black, one red) and each wire was labeled depending on its function. For example one of the wires was labeled MF for Move-Forward (by my best guess).
The Overall Setup:
My best guess for how the car runs is that it essentially uses the receiver to process signals from the remote control. The receiver then sends a pair of HIGH or LOW signals to each DC motor.
What You’ll Need
Here’s a list of what I ended up using for this project.
• Arduino Leonardo (or equivalent) with mini-USB cable
• Computer with proper Arduino programs installed
• Remote Controlled Car
• Sharp Distance Sensor 2D120X (Infrared Proximity Sensor)
• SN754410 H-Bridge
• Heat Sink for the SN754410 H-Bridge
• Oscilloscope (plus Voltage Probe) or Multimeter
• Breadboard (for prototyping)
• Philips Screwdriver
• Wire Cutters
• Wire Strippers
• Electrical Wire
• Perfboard (for the final circuit)
• Solder and Solder Gun
• Hot glue gun
• 2x 9v Batteries (one for the Arduino and one for the Remote Control)
• 4x AA Batteries (for the car)
• Helping-Hand tool (optional)
• Alligator Clips (optional)
• Zipties (optional)
For more detail: RC Car Anti-Crash System Using Arduino
- How did the author choose the RC car?
The author selected an inexpensive ~$20 car from Amazon to avoid ruining an expensive vehicle during the project. - What type of signal does the car use for control?
The car uses digital logic where voltages go either HIGH or LOW to control direction and speed. - Which chip controls the motors on the circuit board?
A receiver chip with four pins is used to process signals and control both direction and speed. - What component drives the current to the DC motors?
H-Bridges are used on the circuit board to provide enough current to drive the DC motors. - Can the car operate without variable speed?
Yes, the specific car used only has switches for direction, implying it operates on simple digital inputs rather than variable speeds. - What sensors are required for the anti-crash feature?
An Infrared Proximity Sensor, specifically the Sharp Distance Sensor 2D120X, is used to detect walls. - How many batteries are needed for the final setup?
The setup requires two 9v batteries for the Arduino and remote, plus four AA batteries for the car itself. - What tools are necessary for soldering the circuit?
You will need a solder gun, solder, wire cutters, and wire strippers for the final assembly.
