The sensor is a digital sensor. It returns the distance to an object (or objects as we will discuss later) as a byte value expressed in cm. The value of 255 has a special meaning, it indicates there is no object within measuring range. So In theory its minimum range is 0 cm and its maximum range is 254 cm. Ultrasonic sensors measure the distance to or presence of a target object. Locally generated ultrasonic noise at the sensor operating frequency can.
![Frequency Frequency](/uploads/1/2/5/8/125828867/480281708.png)
Lego Mindstorms EV3 brick
Lego Mindstorms EV3 (evolution 3) is the third generation robotics kit in Lego's Mindstorms line. It is the successor to the second generation Lego Mindstorms NXT 2.0 kit. The 'EV' designation refers to the 'evolution' of the Mindstorms product line. '3' refers to the fact that it is the third generation of computer modules - first was the RCX and the second is the NXT. It was officially announced on January 4, 2013 and was released in stores on September 1, 2013. The education edition was released on August 1, 2013.[1] There are many competitions using this set. Among them are the First Lego League and the World Robot Olympiad.
Overview[edit]
The biggest change from the Lego Mindstorms NXT and NXT 2.0 to the EV3 is the technological advances in the programmable brick. The main processor of the NXT was an ARM7 microcontroller, whereas the EV3 has a more powerful ARM9 CPU running Linux. A USB connector and Micro SD slot (up to 32GB) are new to the EV3. It comes with the plans to build 5 different robots: EV3RSTORM, GRIPP3R, R3PTAR, SPIK3R, and TRACK3R. Lego has also released instructions online to build 12 additional projects: ROBODOZ3R, BANNER PRINT3R, EV3MEG, BOBB3E, MR-B3AM, RAC3 TRUCK, KRAZ3, EV3D4, EL3CTRIC GUITAR, DINOR3X, WACK3M, and EV3GAME. It uses a program called Lego Mindstorms EV3 Home Edition, which is powered by LabVIEW, to write code using blocks instead of lines. However it can also be programmed on the actual robot and saved.[2]
The EV3 Home (31313) set consists of: 1 EV3 programmable brick, 2 Large Motors, 1 Medium Motor, 1 Touch Sensor, 1 Color Sensor, 1 Infrared Sensor, 1 Remote Control, cables, USB cable, and 585 TECHNIC elements.[2]
The Education EV3 Core Set (45544) set consists of: 1 EV3 programmable brick, 2 Large Motors, 1 Medium Motor, 2 Touch Sensors, 1 Color Sensor, 1 Gyroscopic Sensor, 1 Ultrasonic Sensor, cables, USB cable, 1 Rechargeable battery and 547[3] TECHNIC elements.[2]
An expansion set for the Educational Core Set, which can be bought separately, contains 853 Lego elements. However, the expansion set and the educational set combined do not contain enough components necessary to build most robots of the retail set. This contrasts with the NXT; the educational set combined with the resource set could build any of the retail designs. The EV3 educational set was released a month earlier than the retail set, on August 1, 2013. Robots that can be built with the core education set are the EV3 educator robot, the GyroBoy, the Colour Sorter, the Puppy and the Robot Arm H25. Robots that can be built with the expansion set are the Tank Bot, the Znap, the Stair Climber, the Elephant and a remote control. Another robot that can be built with a pair of core set and an expansion set is the Spinner Factory.NXT’s Hitechnic sensors Blocks can be used with the EV3&NXT.
![Ultrasonic frequency spectrum Ultrasonic frequency spectrum](/uploads/1/2/5/8/125828867/676838374.jpg)
NXT’s sensors can be used with the EV3.It can boot an alternative operating system from a microSD card, which makes it possible to run ev3dev, a Debian Linux-based operating system.
EV3 | NXT | RCX | |
---|---|---|---|
Release Date | September 2013 | July 2006 | 1998 |
Display | 178×128 pixel Monochrome LCD | 100×64 pixel Monochrome LCD | segmented Monochrome LCD |
Main Processor | TISitara AM1808 (ARM926EJ-S core) @300 MHz | AtmelAT91SAM7S256 (ARM7TDMI core) @48 MHz | HitachiH8/300 @16 MHz |
Main Memory | 64 MB RAM 16 MB Flash microSDHC Slot | 64 KB RAM 256 KB Flash | 32 KB RAM 16 KB ROM |
USB Host Port | Yes | No | No |
WiFi | Optional dongle via USB port | No | No |
Bluetooth | Yes | Yes | No |
Connects to Apple/Orange/Banana devices | Yes | No | No |
Compatibility[edit]
All NXT sensors, motors, and building elements work with EV3 and are recognized as NXT sensors/motors when plugged in. EV3 sensors do not work with the NXT, but EV3 motors do. The NXT brick can be programmed with the EV3 software, but lacks some software features. When you use the EV3 software to program the NXT, you must download extra programming-blocks, such as the UltraSonic sensor (which is included in the standard NXT kit, but not the standard EV3 kit). The EV3 brick cannot be programmed with the standard NXT software, but some third party software supports both systems.[5]
Notable robots made with the EV3 platform[edit]
- The Braigo is a robotic Braille printer designed by Shubham Banerjee, a 12-year-old boy from Santa Clara, California in the Silicon Valley region. It is a modified version of the BANNER PRINT3R project, designed by Ralph Hempel.[6] Its low cost (US$354) is an advantage over typical Braille printers (which can cost upwards of $2000).
- The CubeStormer III is a Rubik's cube solving robot, the former Guinness World Records record holder for the fastest Rubik's Cube solving robot - 3.256 seconds. The previous record of 5.27 seconds was held by the CubeStormer II, which was built with previous generation NXT parts. The CubeStormer III broke the record on March 15, 2014.
Enhancements[edit]
On the EV3 AM1808 platform, it is possible with a small hack to double the encoder's resolution. By enabling edge triggered interrupts on the encoder B line (called direction line by Lego), it is possible to have 720 increments per turn instead of 360. This enhancement allows for smoother rotation at low speed and better position control.[7][8] This hack was not possible on the NXT due to a hardware limitation. The modified firmware implementing this modification is called EV3.14.[9]
See also[edit]
- Dexter Industries - Sensors for the EV3 [10]
- LeJOS - Firmware and Java API replacement for EV3 programming.
- CoderZ, an online learning environment with an EV3 online simulator
- ev3dev a linux debian os for ev3
References[edit]
- ^Official EV3 Press Release
- ^ abcdHow is the EV3 different from the NXT? - LEGO.com customerservice FAQ - Products - Themes - MINDSTORMS - MINDSTORMS EV3Archived February 24, 2015, at the Wayback Machine
- ^http://brickset.com/sets/45544-1/Education-EV3-Core-Set
- ^Sherrard, Ann; Rhodes, Amy (October 2014). 'Comparison of the LEGO Mindstorms NXT and EV3 Robotics Education Platforms'. Journal of Extension. 52 (5).
- ^'LEGO MINDSTORMS® EV3 Frequently Asked Questions'. Lego.com. The LEGO Group. March 15, 2013. Retrieved October 1, 2013.
Q: Is EV3 backwards compatible with NXT hardware? A: Yes. You can program your NXT intelligent brick using the new EV3 software. However not all software features are supported by the NXT intelligent Brick. You cannot program your EV3 programmable brick with the NXT Software.
- ^'Lego EV3 Additional Projects: BANNER PRINT3R by Ralph Hempel'.
- ^'Development of an improved firmware for the Lego EV3. Technical report'. ICube laboratory. University of Strasbourg. July 2014.
- ^'Hacking the Lego EV3. Lab web page'. ICube laboratory. University of Strasbourg.
- ^'EV3.14: a modified firmware for the Lego EV3'. ICube laboratory. University of Strasbourg. December 2014.
- ^'Dexter Industries Sensors are EV3 Compatible'.
External links[edit]
Wikimedia Commons has media related to Lego Mindstorms. |
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Lego_Mindstorms_EV3&oldid=913933205'
In order to improve the range sensor's accuracy, the code will calculate what the speed of sound is according to the ambient temperature. The formula for the speed of sound through air at a certain temperature is: Vair = (331.3 + 0.606 * Tc) m/s where Vair is the speed of sound and Tc is the temperature in Celsius according to http://en.wikipedia.org/wiki/Speed_of_sound. Once the speed of sound has been calculated, the distance is measured the same way it is in other ultrasonic range sensor codes. The time is multiplied by the speed and then halved leaving you with units of distance to the object.
If you plan on using this in extreme temperatures, be sure to check the temperature sensor's datasheet as they will give a recommended temperature range. Sometimes the temperature sensors will work just fine in a large range but you might need to change the code a little bit to make up for variations of the temperature sensor's output.
Finally, as with all of my code, I am using a simple debug trick my friend taught me. Using a boolean and if statements, you can easily turn serial communication on or off by changing debug to true or false.
I attached the original code file, otherwise the code can be copied directly from here:
/*******************************************************************************************************
********************************************************************************************************
********************************************************************************************************
Improved Ultrasonic Range Sensing Created by Calvin Kielas-Jensen
Using an Arduino UNO, connect a TMP36 temperature sensor data pin to A0 and a 4 pin ultrasonic range sensor with trig pin on digital pin 8 and echo pin on digital pin 9.
This script improves the accuracy of an ultrasonic range sensor by measuring the ambient temperature. Sound moves through air at a speed dependant on the ambient temperature according to the following equation: Vair = (331.3 + 0.606 * Tc) m/s where Vair is the speed of sound and Tc is the temperature in celcius.
Anyone is welcome to use and modify this code as long as I am given credit. Thank you for respecting the open source movement!
******************************************************************************************************** *******************************************************************************************************/
//The majority of this code is taken and modified from the ARDX temperature sensor code and the PING
//sensor code.
int temperaturePin = A0; //Set the temperature pin input float temperature; //Set temperature variable
boolean debug = true; //For serial communication set debug to true, for faster code set debug to false
long duration, cm; //Set time and cm for distance sensing
int trig = 10, echo = 9; //Set pins for trig and echo
void setup() { if (debug) { Serial.begin(9600); } }
void loop() { temperature = (getVoltage(temperaturePin) - 0.5) * 100;
if (debug) { Serial.println(temperature); }
// Give a short LOW pulse beforehand to ensure a clean HIGH pulse: pinMode(trig, OUTPUT); digitalWrite(trig, LOW); delayMicroseconds(2); digitalWrite(trig, HIGH); delayMicroseconds(5); digitalWrite(trig, LOW); duration = pulseIn(echo, HIGH);
cm = microsecondsToCentimeters(duration, temperature); if (debug) { Serial.println(cm); Serial.println('cm'); } }
float getVoltage(int pin) { return (analogRead(pin) * .004882814); //Converting from 0 to 1024 to 0 to 5v }
long microsecondsToCentimeters(long microseconds, long temp) { return (microseconds * (331.3 + 0.606 * temp)) / 2; //Multiplying the speed of sound through a certain temperature of air by the //length of time it takes to reach the object and back, divided by two }