SharpShot Vision (ESP32CAM) × EV3 × EV3 Classroom

This page covers EV3 Classroom (Scratch blocks) only: how to set it up for the SharpShot Vision (ESP32CAM) on MINDSTORMS EV3, how to read every value, the commands it supports and examples. Use the switcher above to change product, host or software.

Setup

What you need

• Sensor: SharpShot Vision (ESP32CAM) (EV3 edition, RJ12 plug). A SPIKE edition is not recognised on an EV3.
• Brick: LEGO MINDSTORMS EV3.
• Cable: the standard cable in the box, or an original LEGO EV3 cable.
• Software: LEGO MINDSTORMS EV3 Classroom (Scratch-style blocks, the same as SPIKE). The easiest start for first-time EV3 users.

Install the software

1. Install EV3 Classroom from the LEGO Education download page.
2. To open an example: download the .lmsp file → "Open" on the EV3 Classroom home screen → connect the EV3 → "Download and Run" at the bottom right.

Make the software see the sensor

No extension and no driver needed. On the EV3 the sensor emulates an original LEGO sensor (most products show up as an "Infrared Sensor"); use the built-in sensor blocks.

• Classroom blocks look like Scratch, but the modes are exactly the same as in the official EV3 software: Proximity / Beacon / Remote, with the same ranges. See the readings below.
• Some products come with MBC My Blocks. They are already inside the example projects; open an example and they are there.

Important

Do not switch modes in the middle of a program. Every time the EV3 switches a sensor mode it stalls for about 1 s. Pick one mode at the start and use it for the whole run.

Wiring

1. Plug the sensor into EV3 port 1 with the cable (any of 1~4 works; choose the same port in the blocks).
2. Turn the EV3 on first, then plug in the sensor.
3. Latch up, push the plug in gently.

Set the colour on the sensor first

All SharpShot settings are made on the colour screen and buttons on the back of the sensor; no computer needed:

1. The sensor only starts when plugged into a hub that is already on (the screen first shows "LEGO Sync..."); once the camera image appears it is ready.
2. Short-press the side button to open the settings menu; left / right to choose, OK to enter. In the menu, hold the side button for 1 s to clear that colour set.
3. Colour settings and camera parameters (brightness, contrast, saturation, exposure, white balance, flip, mirror) are saved automatically and used at the next power-on.

Two EV3 firmwares

Warning

EV3 Classroom cannot read the WRO edition (HUE12): on the EV3 it is a third-party sensor (type 95). Use EV3-G (MBC My Blocks), clev3r or Pybricks instead.

First test

1. Download the .lmsp of example 1 on this page, open it, connect the EV3 and press "Download and Run".
2. If the number on the EV3 screen changes with what is in front of the sensor, everything is connected.

FAQ

• The number never changes? Unplug the sensor and plug it back in (the EV3 must be on first).
• Some examples have no Classroom version? Examples marked "Pybricks / EV3 MicroPython / clev3r only" use a mode the Classroom blocks cannot read.
• The program hiccups now and then? It switches sensor modes; each switch costs about 1 s. Use one mode only.

Reading values (School edition)

The EV3 sees a stock LEGO sensor; read it with the stock Classroom sensor blocks.

hue hue

Range	Meaning
-1~100	hue of sample point S1, 0100 (hue ring 0240 scaled); −1 = black/white/grey (saturation < 10); 0 when S1 is not set

Value	Block	Decode	Mode
hue	Infrared Sensor → Proximity	the value	mode 0

saturation saturation

Range	Meaning
0~100	saturation of sample point S1, 0~100

Value	Block	Decode	Mode
saturation	Infrared Sensor → Beacon proximity, channel 1	the value	mode 1

brightness value

Range	Meaning
0~100	brightness (HSV value) of sample point S1, 0~100

Value	Block	Decode	Mode
brightness	Infrared Sensor → Beacon heading, channel 2	the value	mode 1

motion motion

Range	Meaning
0~100	whole-frame motion 0~100 (more change = larger)

Value	Block	Decode	Mode
motion	Infrared Sensor → Beacon proximity, channel 2	the value	mode 1

blob X blobX

Range	Meaning
0~100	blob centre X 0~100, left = 0; 0 when not found

Value	Block	Decode	Mode
blob X	Infrared Sensor → Beacon heading, channel 3	the value	mode 1

blob Y blobY

Range	Meaning
0~75	blob centre Y 0~75, bottom = 0, top = 75; 0 when not found

Value	Block	Decode	Mode
blob Y	Infrared Sensor → Beacon proximity, channel 3	the value	mode 1

blob width blobW

Range	Meaning
0~100	blob width W 0~100; 0 = not found

Value	Block	Decode	Mode
blob width	Infrared Sensor → Beacon heading, channel 4	the value	mode 1

blob height blobH

Range	Meaning
0~75	blob height H 0~75; 0 when not found

Value	Block	Decode	Mode
blob height	Infrared Sensor → Beacon proximity, channel 4	the value	mode 1

Not readable here：blob area, blob found. Use Arduino / mBlock / micro:bit for these.

Reading values (WRO edition)

The EV3 sees a stock LEGO sensor; read it with the stock Classroom sensor blocks.

spot 1~12 colour code spotColor

Range	Meaning
0~255	101B = colour code of spots S1S12: 0239 colour (hue 0255 scaled to 0239), 240245 white (saturation < 30, lower = larger), 246~250 black (value < 30, darker = larger), 255 = spot not enabled

This product does not emulate a stock LEGO sensor, so stock blocks cannot read it; use the MBC custom block included with the examples (see setup above).

spot 1~12 vividness spotVivid

Range	Meaning
0~255	202B = vividness (saturation) of spots S1S12, 0~255: black = 1, white/colour = actual saturation; 0 when the spot is not enabled

This product does not emulate a stock LEGO sensor, so stock blocks cannot read it; use the MBC custom block included with the examples (see setup above).

Examples (School edition)

Example 1: What does the camera see? All 8 numbers at once

What this example does: Mode 1 sends 8 numbers at once: colour, saturation, brightness, motion, and the X, Y, width and height of the colour blob. Show them all on the EV3 screen and compare with the camera picture to understand each one.

What you need:

• SharpShot (school edition) (EV3 edition)
• EV3 brick

How to connect: SharpShot (school edition) in port 1. Camera setup: short-press the side button for the menu → left/right to "2:TRACK" → confirm → aim the crosshair at the ball, set the position, tolerance and minimum area in turn → confirm to save.

Download the program (pick your software):

⬇ EV3 Classroom

Step by step:

1. Clear the screen
2. Repeat forever
   • Colour: red 0 or 100, yellow ≈17, green ≈33, blue ≈67, -1 = black/white/grey
   • Saturation 0~100
   • Brightness 0~100
   • How much the picture moved 0~100
   • Blob horizontal position 0~100
   • Blob vertical position 0~75
   • Blob width, 0 = not found
   • Blob height, bigger when closer
   • Wait 0.1 s

What you should see: Move the ball left and right in front of the lens and X follows; bring it closer and W and H grow; take it away and X, Y, W, H all read 0.

FAQ:

• The camera screen stays on "LEGO Sync..."? The camera only starts when plugged into an EV3 that is already on. Turn the EV3 on first, then plug in the camera.
• X, Y, W, H always read 0? 2:TRACK has not been set up, or the ball colour is outside the tolerance.

Example 2: Traffic-light robot: go on green only

What this example does: Mode 0 reads only the "colour". Drive forward on green, stop on anything else (red).

What you need:

• EV3 brick + Education base robot (left wheel on B, right wheel on C)
• SharpShot (school edition) (EV3 edition)
• One red and one green card

How to connect: SharpShot (school edition) in port 1, mounted at the front with the lens facing forward.Camera setup: short-press the side button for the menu → left/right to "1:COLOR" → confirm → aim the crosshair at the colour to learn, set the position and tolerance in turn → confirm to save.

Download the program (pick your software):

⬇ EV3 Classroom

Step by step:

1. Repeat forever
   • If the colour is between 25 and 45 (green)
     • Green: drive forward
     • Otherwise:
       • Not green: stop

What you should see: Hold the green card in front of the lens and the robot drives; swap to the red card and it stops.

FAQ:

• The camera screen stays on "LEGO Sync..."? The camera only starts when plugged into an EV3 that is already on. Turn the EV3 on first, then plug in the camera.
• It does not go on green either? Run example 1 to see the real HUE of your green card, then change 25 and 45 in the program.

Example 3: Burglar alarm: beep when something moves

What this example does: The 4th number of mode 1 is "how much the picture moved". Point the camera at a doorway; when someone walks past the number jumps, and above 20 the EV3 beeps. No camera setup needed.

What you need:

• SharpShot (school edition) (EV3 edition)
• EV3 brick

How to connect: SharpShot (school edition) in port 1, lens pointing at the area to watch, held steady.

Download the program (pick your software):

⬇ EV3 Classroom

Step by step:

1. Repeat forever
   • Show the motion value on screen
   • If the motion value is greater than 20
     • Something is moving: beep!

What you should see: Quiet when the picture is still; wave a hand in front of the lens and the EV3 beeps.

FAQ:

• The camera screen stays on "LEGO Sync..."? The camera only starts when plugged into an EV3 that is already on. Turn the EV3 on first, then plug in the camera.
• It beeps even when nobody is there? Flickering lights or a shaking camera. Raise 20 (for example 35).

Example 4: Turn to look at the ball

What this example does: The robot spins on the spot to keep the ball in the middle of the picture: ball on the left means turn left, on the right means turn right, in the middle means stop; no ball means spin to search.

What you need:

• EV3 brick + Education base robot (left wheel on B, right wheel on C)
• SharpShot (school edition) (EV3 edition)
• A brightly coloured ball

How to connect: SharpShot (school edition) in port 1, mounted at the front with the lens facing forward.Camera setup: short-press the side button for the menu → left/right to "2:TRACK" → confirm → aim the crosshair at the ball, set the position, tolerance and minimum area in turn → confirm to save.

Download the program (pick your software):

⬇ EV3 Classroom

Step by step:

1. Repeat forever
   • If the blob width = 0 (ball not found)
     • Cannot see the ball (width = 0): spin slowly on the spot to look for it
     • Otherwise:
       • If X is less than 40 (left)
         • Ball on the left: turn left
         • Otherwise:
           • Otherwise, if X is greater than 60 (right)
             • Ball on the right: turn right
             • Otherwise:
               • Ball in the centre: stop

What you should see: Move the ball left and right in front of the robot and its nose follows the ball.

FAQ:

• The camera screen stays on "LEGO Sync..."? The camera only starts when plugged into an EV3 that is already on. Turn the EV3 on first, then plug in the camera.
• Left and right are swapped? Swap -15 and 15 in the two tank steps.

Example 5: Chase the ball: stop when close enough

What this example does: Example 4 made to drive: aim at the ball while driving forward, and stop when the ball height H is big enough (close enough).

What you need:

• EV3 brick + Education base robot (left wheel on B, right wheel on C)
• SharpShot (school edition) (EV3 edition)
• A brightly coloured ball

How to connect: SharpShot (school edition) in port 1, mounted at the front with the lens facing forward.Camera setup: short-press the side button for the menu → left/right to "2:TRACK" → confirm → aim the crosshair at the ball, set the position, tolerance and minimum area in turn → confirm to save.

Download the program (pick your software):

⬇ EV3 Classroom

Step by step:

1. Repeat forever
   • If width = 0 (ball not found)
     • Cannot see the ball: spin on the spot to look for it
     • Otherwise:
       • Otherwise, if H is greater than 30
         • Ball height greater than 30 (close enough): stop
         • Otherwise:
           • Steering power turn = (X − 50) × 0.6: positive when the ball is to the right
           • Left wheel = 25 + turn, right wheel = 25 − turn: aim at the ball while driving forward

What you should see: Put the ball on the floor: the robot turns to it, drives over and stops in front of it.

FAQ:

• The camera screen stays on "LEGO Sync..."? The camera only starts when plugged into an EV3 that is already on. Turn the EV3 on first, then plug in the camera.
• It stops while still far away? Raise 30.

Still stuck? Leave a message on Contact us with the software you use and a screenshot of your program, and we will help.

Examples (WRO edition)

Note

These examples have no version for this software: Example 1: What colour does spot S1 see?; Example 2: Colour announcer: show the colour name on screen; Example 3: Traffic pillar: stop on red, go on green; Example 4: Stop at the black line; Example 5: Three spots left, middle, right: where is the red?

More questions

• The EV3 shows an infrared sensor? Expected: the sensor emulates a LEGO sensor so the stock blocks can read it.
• A short freeze when switching modes? The EV3 needs about 1 s per mode change. Stick to one mode during a run.

Still stuck? Contact us with your software and a screenshot of the program.

Downloads

• Download centre (libraries, firmware, catalogue for every product)

Sources

• Host and software list：_build/guides.json
• Values and commands：_build/protocol/cam_school.json、_build/protocol/cam_wro.json (single source of truth)
• Setup：_build/guides/software/ev3-classroom.en.md、_build/guides/product/esp32cam/ev3-classroom.en.md
• Examples：sensors/esp32cam/ev3-examples(-wro).md