Reading it on micro:bit

Warning

v1 not yet hardware-verified: the value layout is final and passes the computer-side tests, but real-hardware numbers (fps, line-following thresholds, I2C pins) may change after bench testing.

The SharpShot Vision (Universal I2C edition) is read over I2C exactly like on Arduino; a micro:bit V1 / V2 reads it with the built-in MakeCode I2C functions at address 0x4C. Value numbers and commands are the same as in Reading it on Arduino; every slot is in the value reference: I2C, full programs in the micro:bit examples.

Wiring

1. Camera SDA to P20 of the breakout, SCL to P19, GND to GND.
2. It must use an external 5 V supply (ESP32 camera + screen draw a lot), not the micro:bit 3V pin; share the supply GND with the micro:bit.

Caution

I2C pins are provisional, pending hardware tests: on the camera side they are currently SDA = IO3, SCL = IO1.

Smallest working program (MakeCode JavaScript)

Switch to Color tracking ③ Standard and plot color 1's position on the LEDs (values 14 = 0x100x13: X, Y, area %, count):

const CAM = 0x4C

// Read k consecutive values from number id (k <= 16), each int16 low byte first
function camRead(id: number, k: number): number[] {
    pins.i2cWriteNumber(CAM, id, NumberFormat.UInt8LE, false)
    basic.pause(2)
    const buf = pins.i2cReadBuffer(CAM, 2 * k, false)
    const out: number[] = []
    for (let i = 0; i < k; i++) out.push(buf.getNumber(NumberFormat.Int16LE, 2 * i))
    return out
}

// Command E0: switch to Color tracking ③ Standard
const cmd = pins.createBuffer(3)
cmd[0] = 0xE0
cmd[1] = 1
cmd[2] = 3
pins.i2cWriteBuffer(CAM, cmd, false)

basic.forever(function () {
    const v = camRead(0x10, 4)          // color 1: X, Y, area, count
    basic.clearScreen()
    if (v[0] > 0) {
        led.plot(Math.idiv(v[0] * 5, 160), Math.idiv(v[1] * 5, 120))
    }
    basic.pause(100)
})

Paste it into the MakeCode JavaScript tab; switch back to Blocks to see the matching blocks. The MBC MakeCode extension (pxt-mbc-sensors) has no SharpShot Vision blocks yet.

Camera mode 5 object detection

The camera sorts the objects in the picture from largest to smallest (object 1 = largest) and gives each an object code = color × 10 + shape (13 = a triangle of target 1, 0 = none). Shapes: 0 other, 1 circle, 2 ellipse, 3 triangle, 4 square, 5 rectangle, 6 pentagon, 7 hexagon, 8 star, 9 trapezoid. X, Y is the centroid of the object; only target colors 1~8 count. Mode number 51 = ① Object list, 52 = ② Object detail. Split the code: color = code ÷ 10 (whole number), shape = remainder of code ÷ 10.

The value table is the same as for Arduino: 51 has 4 values per object (color, shape, X, Y) and the object count at 0x30; 52 has 10 values per object (plus width, height, area %, angle, vertices, track id) and the count at 0x60 (full table in How Arduino reads it). This program switches to the object list (51), plots the largest object on the LEDs and shows its code on button A:

const CAM = 0x4C

// Read k consecutive values from number id (k <= 16), each int16 low byte first
function camRead(id: number, k: number): number[] {
    pins.i2cWriteNumber(CAM, id, NumberFormat.UInt8LE, false)
    basic.pause(2)
    const buf = pins.i2cReadBuffer(CAM, 2 * k, false)
    const out: number[] = []
    for (let i = 0; i < k; i++) out.push(buf.getNumber(NumberFormat.Int16LE, 2 * i))
    return out
}

// Command E0 [5, 1]: switch to Object detection ① Object list
const cmd = pins.createBuffer(3)
cmd[0] = 0xE0
cmd[1] = 5
cmd[2] = 1
pins.i2cWriteBuffer(CAM, cmd, false)

basic.forever(function () {
    const n = camRead(0x30, 1)[0]       // 0x30: object count (mode 51)
    const v = camRead(0x10, 4)          // object 1 (largest): color, shape, X, Y
    basic.clearScreen()
    if (n > 0) {
        led.plot(Math.idiv(v[2] * 5, 160), Math.idiv(v[3] * 5, 120))
    }
    basic.pause(100)
})

input.onButtonPressed(Button.A, function () {
    const v = camRead(0x10, 2)
    basic.showNumber(v[0] * 10 + v[1])  // object 1 code = color × 10 + shape (0 = none)
})

The helpers in the examples, ucReadObject(mode, i), ucObjectCount(mode) and ucShapeName(s), wrap all of this; see micro:bit example 4.

Slot tables and examples

• Value reference: I2C (value 1 = 0x10)
• micro:bit example programs
• Value numbers and commands: Reading it on Arduino

FAQ

• Only zeros or odd numbers? Check the external 5 V is on and GND is shared, then read 0x01 to check the camera mode.
• Reading −32768? That number is not defined in the current camera mode.