Common questions

Please look through this book first, the content in the following can be traced in the book.

Choose OpenMV3 M7, OpenMV4 H7, OpenMV4 H7 Plus or OpenMV RT1062?

The latest version OpenMV4 H7 Plus or OpenMV RT1062 is recommended, which has higher performance, higher resolution and more functions.

What are the differences between OpenMV3 M7, OpenMV4 H7, OpenMV4 H7 Plus, and OpenMV RT1062?

• perpheral is different，look it through ：all kinds of perpheral in pyb

Key point: OpenMV2 cannot use apriltag in the algorithm, but OpenMV3 can. The higher the version, the more functions it has.\ Maximum supported resolution: OpenMV2 320x240; OpenMV3 640x480; OpenMV4 752x480 (MT9V034 global shutter module); OpenMV4 Plus or OpenMV RT1062 2592x1944.

Is OpenMV open source?

Yes, fully open source, github: https://github.com/openmv/openmv

What should I do if there is an error in the running process?

First, upgrade the IDE and firmware to the latest versions.

See Common Error Tips\ See Common Faults

How to view the firmware version.

After connecting the OpenMV, look at the arrow in the picture below.

How to upgrade firmware

See Upgrade Firmware

How to open terminal/check the content of print

See 10-minute quick start

What's the difference between OpenMV and OpenCV？

OpenMV is a hardware project，integrating arithmetic ofimage，hardware is used specially(open source).

OpenCV is a universal software project which need the support of operating system since it need transplant and cut out quite an amount of code when run inflush bonding.

If the arithmetic of OpenMV belongs to transplant from OpenCV？

No, arithmetic is entirely rewritten since OpenMV is designed for computer and not suitable for flush bonding to use.

What's the advantage of OpenMV compared with Raspberry Pi?

• Consumptiom, OpenMV only need 100MA or140MA while running arithmetic. You can use USB to supply power. Raspberry Pi need 700MA,and can’t use USB to supply power.

• Easy to develop. The development of OpenMV is similar with Arduino, just need ten minutes to run. Raspberry Pi need install OpenCV, Numpy and any other software without IDE.

• FPS

Of course, performance is a shortcoming.

What kind of language does OpenMV use to programme?

Python, specifically MicroPython. See: Python background knowledge

Can OpenMV programme in language C ？Can it use IAR or Keil to programme

You can use C language, but it is not necessary. Using Python has many advantages. If you want to write the underlying algorithm, see: Add algorithm to source code

You can't use IAR or Keil to programme since OpenMV is based on project MicroPython.If use IAR or Keil, it is like give up project OpenMV, then you need to start over.

How to compile the firmware of OpenMV?

See: Compile firmware

GCC on Ubuntu。

Can the firmware of OpenMV compile under Windows/IAR/Keil？

No. Please use Ubuntu and GCC.there is no recommendation doing the work in Windows.

Will it run slowly if OpenMV use MicroPython？

Indeed, it will be a little bit slower than use language C ,however,it won't be much slower.

• The algorithm of the kernel code is writen in C language
• The first time you run, your script will be compiled as bytecode automatically by MicroPython（just like your computer）

Can OpenMV run the code off-line？

Yes, see: 10-minute tutorial

Is the development of OpenmMV difficult?

It is not so hard since it like lighten a LED in Arduino. The first Hello World will cost less than ten minutes.

If want to track a small ball, just run the example code which cost less than five minutes.

Is Python difficult?

Python is praised as one of the most easy language to control.

• If you have previous programming experience in C/C++/Java (or any other language), I recommend \ Liao Xuefeng's Python Tutorial

• If you have no programming experience before, it is recommended to\ Learn Python the hard way

What if I can’t write logic? Namely write two functions toether.

This type of person has no programming experience. Recommended\ Stupid way to learn Python

Here are two options：

• I won’t learn it any more, I choose to pay some money to find someone else to develop.
• Acquire the knowledge of program(not just learn Python)
  • Look through the stupid way to learn Python first.
  • Learn more examples to find out using method of varieties of module.
  • Sort out your own logic of need.

May I use the library sunch as NumPy, PIL？

No, you can’t use it on MicroPython as a result of that these librarys are from Cpython.

Can OpenMV run neural network(NN)/deep learning？

Yes, currently OpenMV4/OpenMV4 Plus/OpenMV RT supports neural network models such as TensorFlow Lite human detection, cifar10, lenet digital recognition, stam32CubeAi, etc. There will be more in the future.

You can use the online training website ai.singtown.com or www.edgeimpulse.com to train your own neural network model for classification or target point detection, so as to classify or detect any object you want to identify.

What’s OpenMV’s resolution?

OpenMV2 M4 / OpenMV3 M7 / OpenMV4 H7: 300,000 pixels, OV7725 / MT9M114 photosensitive element.\ Commonly used in the program:

• QQVGA: 160x120
• QVGA: 320x240

Max support：

• VGA: 640x480

Annotation: VGA multicolor is a compressed format, don’t in support of image algorithm.

OpenMV4 Plus / OpenMV RT1062 comes standard with the OV5640 module, which can support up to 5 million pixels.

Can OpenMV use high resolution？

The latest OpenMV4 H7 Plus and OpenMV RT1062 can.

OpenMV4 Plus / OpenMV RT1062 comes standard with the OV5640 module, which can support up to 5 million pixels.

In addition, the OpenMV4 Plus has an external 32MB SDRAM and 32MB QSPI Flash, while the OpenMV RT1062 has an external 32MB SDRAM and 16MB Flash, with higher performance.

The other versions cannot.

• Limitations of the sensor
• Limitation of OpenMV’s operational speed
• OpenMV does not have enough memory, OpenMV3 only has 512KB, and OpenMV4 H7 only has 1MB.

Can the OpenMV camera's sensor be replaced?

OpenMV RT, OpenMV4 H7 Plus and OpenMV4 H7 can replace the photosensitive element. In addition to the standard photosensitive element, it also supports MT9V034 global shutter module and Lepton infrared thermal imaging module.

OpenMV3 M7 / OpenMV2 M4 cannot.

• No other photosensitive element driver
• The photosensitive element is BGA attached to the PCB and cannot be replaced
• You can't use higher pixels on OpenMV2/3 projects.

Can OpenMV use dual-channel cameras?

cannot.

Can OpenMV use external camera？Such as USB camera。

cannot.

What’s the FPS of OpenMV？

How far is the identification distance of OpenMV？

Standard lens：

Object whose size is similar with ping-pong ball：0.5m~1m。

Face detection：1m

See: Background knowledge of image processing

Is the lens of OpenMV changeable?

Yes, standard M12 size lens.

What’s the difference between different lens？

See: Background knowledge of image processing

How far can telephoto lens look to?

Object whose size like ping pong ball：3m。

See: Background knowledge of image processing

What algorithms does OpenMV have?

• Color tracking
• Find qrcodes
• Face tracking
• Find lines
• Template macthing
• Keypoints detection
• Eyes detection
• HAAR，LBP，HOG
• Save image
• Record vidieo
• Edge detection
• Iris detection
• Find line
• Optical flow
• Face detection
• AprilTag

See: [OpenMV image processing method] (/image/README.md)

For various algorithm documents, see: image processing

Can OpenMV detect number？

Mnist number recognition, see: Mnist number recognition

Template matching, see: Template matching

Can OpenMV detect letter？

Template matching, see: Template matching

Can OpenMV detect Chinese character？

Template matching, see: Template matching

Can OpenMV detect shape？

Circle recognition, see: Circle recognition

Rectangle recognition, see: Rectangle recognition

Template matching, see: Template matching

Can OpenMV find face？

Yes.

Can OpenMV detect qrcode？

Yes, see: Scan code recognition

Can OpenMV detect laser spot？

Yes ,color detection。

Can OpenMV communicate with other chips？

Yes,\ Serial communication up\ Serial communication down

Can OpenMV communicate with Arduino/51/STM32？

Yes,\ Serial communication up\ Serial communication down

How should OpenMV communicate with PLC？

RS232 and RS485 are serials of PLC. Using one module TTL-RS232or TTL-RS485,then that’s it. \ Serial communication up\ Serial communication down

Can OpenMV communicate with computer？

Yes. \ Use serial or USB to communicate

USB: [USB-VCP class/documentation] (http://docs.openmv.io/library/pyb.USB_VCP.html?highlight=usb)

Can OpenMV drive Stepping motor/DC motor/Servo?

Yes, see: [Various motors] (/MCU/motor.md)

How many servos can OpenMV drive?

OpenMV2 2, OpenMV3 3, OpenMV4 H7 3, OpenMV4 H7 Plus 2, OpenMV RT1062 4.\ Using PCA9685, it can be expanded to 16 channels or more.

see：all kinds of motor

Can OpenMV be used in autopilot？

Yes with serial. Furthermore, \ There are pact OpenMV and MavLink.

How OpenMV supply power？

Choose one of the following, you can also supply power at the same time

• USB supply power directly
• Vin-GND link with voltage at an arrange from 3.7V to 5V，recommend 5V

What’s for the OpenMV’s pin of 3.3V?

It is the 3.3V output terminal of the voltage, which can power other modules.

Can OpenMV use li battery to supply power?

Yes, li battery is usually 3.7V

What’s OpenMV’s working voltage?

3.3V.

However, the OpenMV2 M4/OpenMV3 M7/OpenMV4 H7/OpenMV4 H7 Plus with STM32 as the main controller is 5V tolerant (if there is a 5V input, the chip can recognize 1 and work normally, but the output is always 3.3V).

The master controller is IMXRT's OpenMV RT 3.3V tolerant (IO input cannot exceed 3.3V).

Why is it so hot when OpenMV run the code?

It is okay about 50°.

How many pins does LCD take up?

P0, P2, P3, P6, P7, P8

See OpenMV accessories

Is LCD use SPI？

yes

What’s LCD’s resolution？

sensor.QQVGA2: 128x160

Can it transmit wireless image ？

Yes.

OpenMV2 M4/OpenMV3 M7/OpenMV4 H7/OpenMV4 H7 Plus uses the WiFi expansion board.

OpenMV RT has built-in WiFi.

See OpenMV accessories

What’s the usefulness of OpenMV SDcard？

Can be used to store images or videos.

How big is OpenMV ‘s SDcard max support?

32G