Table of Contents
People have this question that…
How accurate is FRC rangefinder?
Let’s find out.
FRC How Accurate Is the Rangefinder?
The FRC rangefinders are very accurate but not as accurate as a laser rangefinders. The accuracy of the FRC rangefinder depends on how well you can hold it steady and how close to your target you can get. If you are shooting at a small object like a coin or a penny, then the FRC will be more accurate than if you were shooting at something much larger like a car.
How does the Ultrasonic Range Finder Measures Distance?
On the front of the ultrasonic rangefinder is two metal cylinders. These are transducers. Transducers convert mechanical forces into electrical signals. In the ultrasonic range finder, there is a transmitting transducer and receiving transducer.
The transmitting transducer converts an electrical signal into an ultrasonic pulse, and the receiving transducer converts the reflected ultrasonic pulse back into an electrical signal.
If you look at the back of the range finder, you will see an IC behind the transmitting transducer labeled MAX3232. This is the IC that controls the transmitting transducer.
Behind the receiving transducer is an IC labeled LM324. This is a quad Op-Amp that amplifies the signal generated by the receiving transducer into a signal that’s strong enough to transmit to the Arduino.
The HC-SR04 ultrasonic range finder has four pins:
- Vcc– supplies the power to generate the ultrasonic pulses
- GND– connected to ground
- Trig– where the Arduino sends the signal to start the ultrasonic pulse
- Echo– where the ultrasonic range finder sends the information about the duration of the trip taken by the ultrasonic pulse to the Arduino
To initiate a distance measurement, we need to send a 5V high signal to the Trig pin for at least 10 µs. When the module receives this signal, it will emit 8 pulses of ultrasonic sound at a frequency of 40 kHz from the transmitting transducer.
Then it waits and listens at the receiving transducer for the reflected signal. If an object is within range, the 8 pulses will be reflected back to the sensor. When the pulse hits the receiving transducer, the Echo pin outputs a high-voltage signal.
The length of this high voltage signal is equal to the total time the 8 pulses take to travel from the transmitting transducer and back to the receiving transducer.
However, we only want to measure the distance to the object, and not the distance of the path the sound pulse took.
Therefore, we divide that time in half to get the time variable in the d = s x t equation above. Since we already know the speed of sound (s), we can solve the equation for distance.
Distance Measurement Using the HC-SR04 Ultrasonic Range Finder
The HC-SR03 is a great little device because it’s easy to use and inexpensive. It works with any Arduino board and comes with everything you need except a battery. You just plug in the HC-SR03 and connect the wires to the Arduino.
If you have never used an ultrasonic range finder before, here is what you do:
- Connect the VCC wire to +5 volts
- Connect the GND wire to ground
- Connect the Trig wire to digital pin 9 on the Arduino
- Connect the Echo wire to analog pin 0 on the Arduino
- Plug the HC-SR03 into the USB port of your computer
- Open up the Arduino IDE software
- Upload the code to the Arduino
- Run the program
- Place the HC-SR03 near an object and wait until the LED flashes green
- Wait for another second or so and then move the HC-SR03 away from the object
- Repeat steps 10 through 11 as many times as necessary to determine the distance between the HC-SR03 sensor and the object
- Calculate the distance using the following formula: d s x t where: d – Distance measured – Speed of sound t – Time elapsed
- Save the data to the SD card
- Unplug the HC-SR03
You should now have a file called “distance.txt” on your SD card containing all the distances you measured.
How Accurate Is the Rangefinder?
The accuracy of the HC-SR03 depends on how well you place the sensor next to the object being detected. As long as you keep the sensor close to the object, you should get fairly accurate results.
For example, if you are measuring the distance from the sensor to a wall, the sensor may be off by several inches. However, if you are measuring from the sensor to a bookcase, the error could be much less than an inch.
In general, the closer you place the sensor to the object, the more accurate the readings will be.
What Are Some Uses For This Project?
There are lots of uses for this project. Here are some ideas:
- Measure the distance to objects around your house such as walls, furniture, etc.
- Use the distance measurements to create a 3D model of your home
- Create a robot that follows you around the house
- Make a simple alarm system that detects intruders
- Build a remote-controlled toy car
FRC How Accurate Is the Rangefinder?
Laser Rangefinder Buying Guide
Laser Rangefinder
Before buying a laser rangefinder, make sure you understand the features and capabilities of the unit. Laser rangefinders come in two basic types: active and passive.
Active lasers send out light waves and detect when they bounce off of an object. Passive lasers don’t emit light; instead, they reflect the light coming from other sources.
Both types of laser rangefinders work best at night, but active units can also operate during daylight hours.
Most laser rangefinders include a display screen that shows the distance to the target. The display usually includes a small LCD panel that displays the distance to the target along with the time remaining.
Some laser rangefinders also include a compass feature that allows them to automatically adjust their direction based on the location of the target.
If you plan to use your laser rangefinder outdoors, it is important to know whether the device has a waterproof case. If not, you will need to purchase one separately.
Some laser rangefinders offer additional features such as automatic tracking, auto-ranging, and GPS coordinates.
When shopping for a laser rangefinder, look for these features:
- A large display screen
- An easy-to-use interface
- Automatic ranging
- Compass function
- Waterproof case
- Auto tracking
- Auto-ranging
- GPS coordinates
- Easy-to-read distance scale
- Long operating time
- Manual focusing
- Wide angle lens
Conclusion
We hope that this article was helpful. If you have any queries feel free to reach out in the comments section below.
