Flashing a NanoPc T3 with DietPi

The NanoPc T3 is a 64 bit octa core single board computer, quite similar to the famous Raspberry Pi boards. It is also often referred to as NanoPi T3 as well.

Hardware Specification

The single board computer has eight cores with up to 1.4GhZ and 1 GB of DDR3 RAM. It has a lot of nice interfaces, the specification below is taken from here.

    SoC: Samsung S5P6818 Octa-Core Cortex-A53, 400M Hz - 1.4G Hz
    Power Management Unit: AXP228 PMU, it supports software power-off and wake-up.
    System Memory: 1GB/2GB 32bit DDR3 RAM
    Storage: 1 x SD Card Socket
    Ethernet: Gbit Ethernet(RTL8211E)
    WiFi: 802.11b/g/n
    Bluetooth: 4.0 dual mode
    Antenna: Porcelain Antenna IPX Interface
    eMMC: 8GB
    Video Input: DVP Camera/MIPI-CSI (two camera interfaces)
    Video Output: HDMI Type-A / LVDS / Parallel RGB-LCD / MIPI-DSI (four video output interfaces)
    Audio: 3.5 mm audio jack / via HDMI
    Microphone: onboard Microphone
    USB Host: 4 x USB 2.0 Host, two type A ports and two 2.54 mm pitch pin-headers
    MicroUSB: 1 x MicroUSB 2.0 Client, Type A
    LCD Interface: 0.5mm pitch 45 pin FPC seat, full color RGB 8-8-8
    HDMI: 1.4A Type A, 1080P
    DVP Camera: 0.5mm pitch 24 pin FPC seat
    GPIO: 2.54 mm pitch 30 pin-header
    Serial Debug Port: 2.54mm pitch 4-pin-header
    User Key: K1 (power), Reset
    LED: 1 x power LED and 2 x GPIO LED
    Other Resources: CPU’s internal TMU
    RTC Battery: RTC Battery Seat
    Heat Sink: 1 x Heat Sink with mounting holes
    Power: DC 5V/2A
    PCB: Six Layer
    Dimension: 100 mm x 60 mm
    OS/Software: uboot, Android and Debian

Overview

The device offers quite a lot considering its small measurements. The picture below is an overview picture taken from here.

The device with the heat sink and attached cables is shown below.

Comparison with the Raspberry Pi Model 3B

It costs about twice as much as the Raspberry Pi 3, but comes with eight cores at 1.4GHz instead of four cores with 1.2GHz, GBit Ethernet instead of just 100 MBit and several additional interfaces. It has a dedicated power switch, supports soft poweroff and provides reset and boot buttons. It comes with an SD card slot instead of micro SD, has only two standard USB ports but also one micro USB port. This port however is not for powering the device, but only for data.

Some remarks at First

The board can get quite warm, so I would recommend buying the heat sins that fit directly on the board as well. The wifi signal is also rather weak, I would recommend investing in the external antenna if the device is in an area with low signal reception. Also it requires an external 5V power source and does not provide a micro USB port for power like similar boards use.

Buying and Additional Information

The board can be obtained for 60$ from here and there also exists a wiki page dedicated to the T3. The images are stored at a One-Click share hoster and the download is very slow. Also the files are not that well organized and can be easily confused with other platforms offered by the same company.

  • Nano PC T3 ($60)
  • Heat sink ($1.99)
  • Power supply ($20)
  • SD card (~ $10)

Additionally there is shipping ($20 to Europe) and also very likely some toll to pay.

Initial Setup

The NanoPi T3 has an internal eMMC storage with 8GB capacity. It comes pre-installed with Android, which is not really useful for my applications. Instead, there exist different ISO images wich can be obtained here. The wiki page documents how to create bootable SD cards with Windows and Linux and there are also scripts offered, which automate the process. Unfortunately, the scripts are not documented well and some of the links are already broken, which reduces the usability of the provided information. Also as the images should be downloaded from some Sharehoster, there is no way of verifying, what kind of image you actually obtained. This is a security risk and not applicable in many scenarios. Fortunately, there also exist alternative images which are more transparent to use.

By default, the device boots from the eMMC flash storage. By pressing the boot button in the lower right corner, we can also boot from the SD card. This is a nice feature, but if you want to reboot the system unattended, then we need to replace the default operating system. In the course of this article, we are going to write an alternative Debian image to the flash memory and boot this OS automatically.

DietPi

DietPi is a Debian based distribution, which claims to be an optimized and lightweight alternative for single board PCs. The number of supported devices is impressive and luckily, also the NanoPC T3 is in the list. It also comes with a list of nice features for the configuration and the backup of the system. DietPi can be dowloaded here and the documentation is available here.

The following steps are requried:

  1. Download the DietPi Image
  2. Write the image to the SD card
  3. Mount the SD card on your desktop and copy the DietPi image to the card
  4. Boot the NanoPC T3 from the card
  5. Flash the DietPi image to the eMMC
  6. Reboot
  7. Configure

Creating a Bootable SD Card

The fist step involves creating a bootable SD card by writing the DietPi image with dd to the card. To do so, download the DietPi image to your local Desktop and then write the file with dd. The process does not differ from other single board machines and is described here. The next step might seem a bit odd. After you finished writing the SD card, mount it on your local Dekstop and copy the DietPi image to the tmp directory of the SD card.The reason we do this is that we need to have a running Linux system so that we can flash the integrated eMMC of the T3. We then use the DietPi Linux zu actually flash the eMMC of the T3 also with the DietPi image. By copying the image we save some time for downloading and we have the image right available in the next step.

Boot the SD Card

Make sure the T3 is powered off and insert the SD card into the board. Hold and keep pressed the boot button and flip the power switch. The T3 then should boot into the DietPi system. It is easier if you attach a monitor and a keyboard to the system for the further configuration. Alternatively, you can also configure the networking settings in advance, by mounting the SD card at the Desktop and edit the configuration files there, but as we simply use this system for installing the actual operating system, this might be a bit too much effort. Press CRTL+ALT+F2 to switch to a new TTY and login. The standard login for the DietPi system is with the user root and password dietpi.

First, create a backup of the original eMMC content, just in case anything does wrong. Use fdisk, to see the available drives.

root@DietPi:~# fdisk -l

Disk /dev/mmcblk0: 15 GiB, 16088301568 bytes, 31422464 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x4d5ca6f7

Device         Boot  Start      End  Sectors  Size Id Type
/dev/mmcblk0p1        2048   133119   131072   64M 83 Linux
/dev/mmcblk0p2      133120 31422463 31289344 14,9G 83 Linux

Disk /dev/mmcblk1: 7,3 GiB, 7818182656 bytes, 15269888 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device         Boot   Start      End  Sectors  Size Id Type
/dev/mmcblk1p1         2048   133119   131072   64M 83 Linux
/dev/mmcblk1p2       133120  1677311  1544192  754M 83 Linux
/dev/mmcblk1p3      1677312  2553855   876544  428M 83 Linux
/dev/mmcblk1p4      2553856 15269887 12716032  6,1G  5 Extended
/dev/mmcblk1p5      2555904  2572287    16384    8M 83 Linux
/dev/mmcblk1p6      2574336  2619391    45056   22M 83 Linux
/dev/mmcblk1p7      2621440 15269887 12648448    6G 83 Linux

Disk /dev/mmcblk1boot1: 4 MiB, 4194304 bytes, 8192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mmcblk1boot0: 4 MiB, 4194304 bytes, 8192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

In the example above you can see my 16GB SD card at /dev/mmcblk0 and the internal eMMC at /dev/mmcblk1. Use dd to create a backup of the whole eMMC like this:

dd if=/dev/mmcblk1 of=/tmp/emmc-original.img bs=512

We now have a backup of the original content at the SD card and can proceed with the actual flashing.

Flashing the DietPi Image to the eMMC

In this step, we flash the DietPi image we copied to the SD card before to the eMMC and overwrite its default Android system. To to so, we use again dd:

dd if=/tmp/DietPi.img of=/dev/mmcblk1 bs=512

This may take a while, be patient. After the image has been written, poweroff the T3 and remove the SD card. Now hold again the boot button and flip the power switch again. This causes the T3 to initialize the new DietPi installation, this time from the internal flash memory. After this step, the system automatically boots from the eMMC flash the next time, without having to press the button.

As a result, we now only utilise the internal flash memory for running the OS, which is not only faster than the SD card, but also allows using the SD card as additional storage. The tool fdisk now shows the eMMC with its two partitions from DietPi:

root@DietPi:~# fdisk -l

Disk /dev/mmcblk0: 7,3 GiB, 7818182656 bytes, 15269888 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x4d5ca6f7

Device         Boot  Start      End  Sectors  Size Id Type
/dev/mmcblk0p1        2048   133119   131072   64M 83 Linux
/dev/mmcblk0p2      133120 15269887 15136768  7,2G 83 Linux

Disk /dev/mmcblk0boot1: 4 MiB, 4194304 bytes, 8192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mmcblk0boot0: 4 MiB, 4194304 bytes, 8192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mmcblk1: 15 GiB, 16088301568 bytes, 31422464 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x4d5ca6f7

Device         Boot  Start      End  Sectors  Size Id Type
/dev/mmcblk1p1        2048   133119   131072   64M 83 Linux
/dev/mmcblk1p2      133120 31422463 31289344 14,9G 83 Linux

 

Configuration

The DietPi comes with a few nice setup tools, which make the installation process rather easy. After logging in, the DietPi will guide you through the installation, but it expects a working Internet connection. You can add the SSID, pre-shared key and additional information in the file /DietPi/dietpi.txt. The following steps are basic and the setup needs to be completed, otherwise you will be bugged with the same menu after every reboot:

  1. The first step is to configure wireless networking. Add your network information to the file mentioned above and reboot. Todo so, you need to abort the setup process, because following the menu did not work for me, as the menu allows only to setup a hotspot instead of connecting to an existing network.
  2. When you login next time, you will be greeted by the dietpi-software dialogue. You can install basic software components such as editors, build essentials etc
  3. The system will now reboot and you are ready go go
  4. Login again and change the root password with passwd and add a new user with adduser $USER and add this user to the sudo group with adduser $USER sudo

You can re-open the configuration menus later by using dietpi-config for the basic setup and dietpi-software for adding new software. Of course for the latter you can always use apt.

Conclusions

The NanoPC T3 is an affordable single board computer with eight cores and 1GB of DDR3 RAM, integrated wireless and bluetooth interfaces, camera interfaces and many other features more. Its mall size renders it an ideal candidate for hardware and software projects based on Linux. The documentation could be improved, especially the transparency of the images and the details of the installation procedure. Also more RAM (as always) would be nice.

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Timelape Photography with the Camera Module V2 and a Raspberry Pi Model B

Recently, I bought a camera module for the Raspberry Pi and experimented a little bit with the possibilities a scriptable camera provides. The new Camera Module V2 offers 8.08 MP from a Sony sensor and can be controlled with a well documented Python library. It allows to take HD videos and shoot still images. Assembly is easy, but as the camera is attached with a rather short ribbon cable, which renders the handling is a bit cumbersome. For the moment, a modified extra hand from my soldering kit acts as a makeshift.

picamInitial Setup

The initial setup is easy and just requires a few steps, which is not surprising because most of the documentation is targeted to kids in order to encourage their inner nerd. Still works for me as well 🙂

Attach the cable to the raspberry pi as described here. You can also buy an adapter for the Pi Zero. Once the camera is wired to the board, activate the module with the tool raspi-config.

configThen you are ready to install the Python library with sudo apt-get install python3-picamera, add your user to the video group with usermod -a -G video USERNAME  and then reboot the Raspberry. After you logged in again, you can start taking still images with the simple command raspistill -o output.jpg. You can find some more documentation and usage examples here.

Timelapse Photography

What I really enjoy is making timelapse videos with the Raspberry Pi, which gives a nice effect for everyday phenomena and allows to observe processes which are usually too slow to follow. The following Gif shows a melting ice cube. I took one picture every five seconds.

Eiswurfel2_kleinerA Small Python Script

The following script creates a series of pictures with a defined interval and stores all images with a filename indicating the time of shooting in a folder. It is rather self explanatory. The camera needs a little bit of time to adjust, so we set the adjustTime variable to 5 seconds. Then we take a picture every 300 seconds, each image has a resolution of 1024×768 pixels.

import os
import time
import picamera
from datetime import datetime

# Grab the current datetime which will be used to generate dynamic folder names
d = datetime.now()
initYear = "%04d" % (d.year)
initMonth = "%02d" % (d.month)
initDate = "%02d" % (d.day)
initHour = "%02d" % (d.hour)
initMins = "%02d" % (d.minute)
initSecs = "%02d" % (d.second)

folderToSave = "timelapse_" + str(initYear) + str(initMonth) + str(initDate) +"_"+ str(initHour) + str(initMins)
os.mkdir(folderToSave)

# Set the initial serial for saved images to 1
fileSerial = 1

# Create and configure the camera
adjustTime=5
pauseBetweenShots=300

# Create and configure the camera
with picamera.PiCamera() as camera:
    camera.resolution = (1024, 768)
    #camera.exposure_compensation = 5

    # Start the preview and give the camera a couple of seconds to adjust
    camera.start_preview()
    try:
        time.sleep(adjustTime)

        start = time.time()
        while True:
            d = datetime.now()
            # Set FileSerialNumber to 000X using four digits
            fileSerialNumber = "%04d" % (fileSerial)

            # Capture the CURRENT time (not start time as set above) to insert into each capture image filename
            hour = "%02d" % (d.hour)
            mins = "%02d" % (d.minute)
            secs = "%02d" % (d.second)
            camera.capture(str(folderToSave) + "/" + str(fileSerialNumber) + "_" + str(hour) + str(mins) + str(secs) + ".jpg")

            # Increment the fileSerial
            fileSerial += 1
            time.sleep(pauseBetweenShots)

    except KeyboardInterrupt:
        print ('interrupted!')
        # Stop the preview and close the camera
        camera.stop_preview()

finish = time.time()
print("Captured %d images in %d seconds" % (fileSerial,finish - start))

This script then can run unattended and it creates a batch of images on the Raspberry Pi.

Image Metadata

The file name preserves the time of the shot, so that we can see later when a picture was taken. But the tool also stores EXIF metadata, which can be used for processing. You can view the data with the exiftool.

ExifTool Version Number         : 9.46
File Name                       : 1052.jpg
Directory                       : .
File Size                       : 483 kB
File Modification Date/Time     : 2016:07:08 08:49:52+02:00
File Access Date/Time           : 2016:07:08 09:19:14+02:00
File Inode Change Date/Time     : 2016:07:08 09:17:52+02:00
File Permissions                : rw-r--r--
File Type                       : JPEG
MIME Type                       : image/jpeg
Exif Byte Order                 : Big-endian (Motorola, MM)
Make                            : RaspberryPi
Camera Model Name               : RP_b'imx219'
X Resolution                    : 72
Y Resolution                    : 72
Resolution Unit                 : inches
Modify Date                     : 2016:07:05 08:37:33
Y Cb Cr Positioning             : Centered
Exposure Time                   : 1/772
F Number                        : 2.0
Exposure Program                : Aperture-priority AE
ISO                             : 50
Exif Version                    : 0220
Date/Time Original              : 2016:07:05 08:37:33
Create Date                     : 2016:07:05 08:37:33
Components Configuration        : Y, Cb, Cr, -
Shutter Speed Value             : 1/772
Aperture Value                  : 2.0
Brightness Value                : 2.99
Max Aperture Value              : 2.0
Metering Mode                   : Center-weighted average
Flash                           : No Flash
Focal Length                    : 3.0 mm
Maker Note Unknown Text         : (Binary data 332 bytes, use -b option to extract)
Flashpix Version                : 0100
Color Space                     : sRGB
Exif Image Width                : 1024
Exif Image Height               : 768
Interoperability Index          : R98 - DCF basic file (sRGB)
Exposure Mode                   : Auto
White Balance                   : Auto
Compression                     : JPEG (old-style)
Thumbnail Offset                : 1054
Thumbnail Length                : 24576
Image Width                     : 1024
Image Height                    : 768
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:0 (2 2)
Aperture                        : 2.0
Image Size                      : 1024x768
Shutter Speed                   : 1/772
Thumbnail Image                 : (Binary data 24576 bytes, use -b option to extract)
Focal Length                    : 3.0 mm
Light Value                     : 12.6

Processing Images

The Raspberry Pi would need a lot of time to create an animated Gif or a video from these images. This is why I decided to add new images automatically to a Git repository on Github and fetch the results on my Desktop PC. I created a new Git repository and adapted the script shown above to store the images within the folder of the repository. I then use the following script to add and push the images to Github using a cronjob.

cd /home/stefan/Github/Timelapses
now=$(date +"%m_%d_%Y %H %M %S")
echo $now
git pull
git add *.jpg
git commit -am "New pictures added $now"
git push

You can add this to you user’s cron table with crontab -e and the following line, which adds the images every 5 minutes,

*/5	*	*	*	*	/home/stefan/Github/Timelapses/addToGit.sh

On a more potent machine, you can clone the repository and pull the new images like this:

cd /home/stefan-srv/Github/Timelapses
now=$(date +"%m_%d_%Y %H %M %S")
echo "$now"
git pull --rebase

The file names are convenient for being able to read the date when it was taken, but most of the Linux tools require the files to be named within a sequence. The following code snippet renames the files into a sequence with four digits and pads them with zeros if possible.

a=1
for i in *.jpg; do
  new=$(printf "%04d.jpg" "$a") #04 pad to length of 4
  mv -- "$i" "$new"
  let a=a+1
done

Animated Gifs

Imagemagick offers a set of great tools for images processing. With its submodule convert, you can create animated Gifs from a series of images like this:

convert -delay 10 -loop 0 *.jpg Output.gif

This adds a delay after each images and loops the gif images infinitely. ImageMagick requires a lot of RAM for larger Gif images and does not handle memory allocation well, but the results are still nice. Note that the files get very large, so a smaller resolution might be more practical.

Still Images to Videos

The still images can also be converted in videos. Use the following command to create an image with 10 frames per second:

avconv -framerate 10 -f image2 -i %04d.jpg -c:v h264 -crf 1 out.mov

Example: Nordkette at Innsbruck, Tirol

This timelapse video of the Inn Valley Range in the north of the city of Innsbruck has been created by taking a picture with a Raspberry Pi Camera Module V2 every 5 minutes. This video consists of 1066 still images.

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