RT1062 accelerometer usage

OpenMV Products
1

Hopefully I was not just too blind and this topic has been covered before. However I could not find information.
I received an RT1062 last week and played with it. First I was a bit disappointed to only have an accelerometer and not full imu like nicla. Then I wanted to check it out and realized that I did not find a suitable example. Checked filter by board.

So do you provide a library for the accelerometer or would you read its data over i2c bus? (schemetic says internal i2c bus)
Is there example code?

2

Here’s what we got for right now. The accelerometer is really basic. I would have loved to include a full IMU, but we didn’t have the cost room. The one we are using is the least expensive one on the market (50 cents), full IMUs start at like 4-5 dollars and up which would have added $10 to the final system cost.

Anyway, it’s really just for tilt sensing, which we will use in the future to allow you to rotate the video as the camera rotates.

# Untitled - By: kwagy - Tue Aug 8 2023

import machine, time

bus = machine.I2C(2)

print(bus.scan())

while(True):
    d = bus.readfrom_mem(0x15, 0x03, 7)
    x = ((d[0] << 8) | d[1]) >> 4
    if x & 0x800: x = x - 4096
    y = ((d[2] << 8) | d[3]) >> 4
    if y & 0x800: y = y - 4096
    z = ((d[4] << 8) | d[5]) >> 4
    if z & 0x800: z = z - 4096
    t = d[6]
    x = x / 1024.0
    y = y / 1024.0
    z = z / 1024.0
    t = (t * 0.586) + 25.0
    t = (t * 9.0/5.0) + 32
    print("%+0.2fx %+0.2fy %+0.2fz %+0.2ft" % (x, y, z, t))
    time.sleep_ms(100)

Besides being an inexpensive IMU, it is the simplest thing imaginable.

3

Thanks for the code!
I am looking forward to play with that device tonight. Having a timer interrupt and do the reading and possibly some (lowpass) filtering in python should be no problem for the processor.

Wow that is really a significant difference in price tag for a cam like that.

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Prices are better now but we designed this back when the chip shortage wasn’t quite over: SMD/SMT IMUs - Inertial Measurement Units – Mouser

Still, it would have added a lot more cost.

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@kwagyeman Never mind the cost of a full IMU (6DOF would be enough, no need for the fiddly magnetometer part), 10$ more on top of the current 120$ isn’t much, it would have made the RT1062 a potential… VIO (Visual Inertial Odometry) on MCU!
Please do not hesitate to add a full IMU, and … a 8x8 ToF sensor on the next release.

Thanks for the accelerometer example anyway.

6

The next camera model we make will have an accelerometer and gyro.

The 8x8 ToF is harder to add. Maybe.

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