MakeBlock (mBot) Block Extension

Read MBC Pathfinder, Ranger, Controller, IMU gyro and Vision sensors with blocks in mBlock 5 on mBot, mBot Ranger and other Makeblock boards: install one extension and six new categories appear, one block per value.

Software: mBlock 5 for PC (Upload mode — the program is flashed to the board).

Install the extension

v2.0.0 (new, for protocol v2 firmware shipped from 2026-10)

v1.0.0 (legacy)

Install steps (once you have the .mext)

1. Open mBlock 5 for PC and add your board under "Devices" (for example mBot).
2. Drag the .mext file into the mBlock window. Six categories appear: Pathfinder, Ranger, Controller, IMU Gyro, Vision and MBC common (the v2.2.0 import file has seven: "Vision" is renamed "SharpShot Vision (legacy)" and a new "SharpShot Vision" category is added).
3. Switch the mode to Upload, start from the board's start block (for example "when mBot starts up") and click "Upload".

Important

Use the MakeBlock edition of the sensor (different factory firmware) connected through the mBot socket board to an RJ25 port. SPIKE, EV3 and I2C editions cannot be plugged into Makeblock boards directly. The v2 extension only works with v2 firmware and the legacy extension only with legacy firmware; the blocks are not interchangeable. Not sure which firmware you have? Drop in the v2 extension and read "MBC common → protocol version": 2 means new firmware.

Note

Blocks follow the mBlock language setting (English, Traditional Chinese or Simplified Chinese).

Boards and ports

Pick the port number on the block; the extension maps it to the right pins for your board. Use these ports:

Tip

On a port that cannot be used, or when the sensor is not connected, reporter blocks return -32768 (never read) or the last value read, and "MBC common → connected?" is false. Check that boolean block first, then the numbers.

mBot2 (CyberPi) has no RJ25 ports and is not supported.

Supported products

Note

The MakeBlock edition of the IMU gyro is new (October 2026). Please contact us before ordering to confirm the edition. The SharpShot Vision uses the "SharpShot Vision" category of v2.2.0 (including camera mode 5 object detection); the mBlock edition is not yet hardware-verified; the "SharpShot Vision (legacy)" category of v2.2.0 (block prefixes "SharpShot Vision (legacy)" / "SharpShot Vision WRO (legacy)", called "Vision" / "Vision WRO" in v2.0.0 / v2.1.0) is for the legacy SharpShot Vision (no longer supported). The PS2 controller is sold in Taiwan only.

Sign conventions

• Negative = line on the left: line position, fine position and last exit direction are negative when the line is left of centre (seen from behind the robot), positive on the right, 0 in the middle.
• Sticks: right / up positive: LX, LY, RX, RY are −100…+100, 0 = centre (released).
• Distance: cm blocks 0–120 (120 = nothing ahead), mm blocks 0–1200; Ranger 8 direction −8…+8 (0 = straight ahead, negative = left, ±8 = no target).
• Hue −1 = grey/black/white: the Vision hue block returns −1 when there is no colour; WRO spot colour code 255 = spot off.
• −32768 = no reading: sensor missing, dropped bytes or checksum error; use the "connected?" block to check.

Blocks

One block per value, returning the number you want (int16); command blocks get an ACK before the module executes them. The table is generated from the value tables:

Tip

When one loop reads many blocks, put an "update all values" block first: reporter blocks within the next 10 ms are served from the cache instead of each waiting for its own serial round trip (about 1 ms each).

📂 Example downloads

Install the v2 extension first, then open an example with mBlock 5 "File → Open from your computer" (all examples use mBot; for another board, change the start block and the port):

Note

These three files were converted from the v1 examples to v2 blocks and have not yet been opened in mBlock 5 for verification (we will re-check once the extension is listed). If a file will not open or blocks show up blank, make sure the v2 extension is loaded, or tell us.

Example 1: mBot PD line following (Pathfinder)

Pathfinder 8-Way on mBot port 1:

1. "when mBot starts up" → wait 1 second (sensor boot) → Pathfinder [port 1] black line mode.
2. Forever:
   • error = Pathfinder [port 1] fine line position (negative = line on the left)
   • turn = error × 0.6 + (error − last error) × 2
   • left speed = base − turn, right speed = base + turn
   • last error = error

When the line is on the left (negative error) the turn is negative; left wheel = base − turn and right wheel = base + turn, so the left wheel slows down and the right wheel speeds up, steering the robot back left onto the line. Start with a base speed of 40. If the robot wobbles, lower 0.6; if it reacts too slowly, raise it.

Example 2: mBot obstacle avoidance (Ranger 8)

Ranger 8-Way on mBot port 3; wait 3 seconds after boot for the 8 lasers to initialise:

1. If Ranger 8 [port 3] nearest distance cm < 20:
   • if nearest direction < 0 (obstacle on the left) → left 40, right −40 (turn right)
   • else → left −40, right 40 (turn left)
2. Else → both wheels 40, straight ahead.

For a smarter version, use "farthest direction" and turn toward the most open side.

Example 3: mBot tank drive (Controller)

Controller on mBot port 4:

1. If Controller [port 4] gamepad connected?:
   • left wheel = Controller [port 4] stick [left stick y] × 0.7
   • right wheel = Controller [port 4] stick [right stick y] × 0.7
2. Else → stop.

Sticks are positive upward (max +100); × 0.7 caps the speed at 70 — raise it for a faster robot.

No readings?

1. "MBC common → connected?" is false: wrong port on the block, the sensor is not the MakeBlock edition, or it runs legacy firmware (use the v1 extension above).
2. -32768: nothing has been read since power-on — check the wiring as above; or this product has no such value (for example channel 9 on an 8-way Pathfinder).
3. Value never changes: check the socket board is seated and the sensor LED is on; "protocol version" reading 2 means the link works.
4. Still stuck: contact us with your board model, the port and the "device ID" reading.

🔧 Plain Arduino works too

The library inside the extension (src/MBC_Sensors.h) can be used in your own Arduino sketch: MBCPort p(1); p.begin(); int16_t pos = p.read(0x01);. The protocol is tiny: the host sends one byte (the value id) and the sensor replies with three bytes (value low, value high, checksum = id ^ low ^ high). See each product's command reference for the packet details.