Friday, 4 December 2020

Inside an AMG8833 thermal imager

Very simple AMG8833 thermal imager


(I took it through it's paces in this video)

For years I had felt he need for a thermal imager or thermal camera to help me find faulty electronic components. But the price tag was prohibitive.

40mA - not very power hungry

I experimented with a single temperature sensor, sweeping a range with model servos. Interesting and entertaining, but not really useful. That was back in 2013. Even later, the cost for the simplest "grid eye" was still a bit on the high side for an experimenter. Until recently.

Bare bones imager

I then found this bare bones / no frills thermal camera here on Banggood. It comes without any matching documentation, let alone a manufacturer name.

PCB Version 5.1.2 from June2020

It has a resolution of 8x8 pixels and sports the "high gain" version of the Grideye. While "high gain" sounds like a good thing, it actually limits the sensor's thermal range to 0-80 degree centigrade.

The AMG8833

The Panasonic GridEye comes in different flavours that is easy to decipher from the part number:

The 88 stands for the 8x8 pixel resolution, the next digit shows the operating voltage 5 for 5volts, 3 for 3.3 volts. And finally a 3 for the "high gain" and a 4 for the "low gain" version, with the low gain version ranging from -20C to 100C. We don't have that in this device so on very cold days, the outside world looks like a blank sheet to the imager.

The next step up is the 32x24 pixels MLX90640 from Melexis, which has a -40 to 300C temperature range. Looking at what 8x8 pixels can do, 32x24 should be awesome. It comes at about twice the cost of the AMG8833 based imager, also from Banggood.


Electronics repair

It all boils down to the question: are 8x8 pixels sufficient to identify hotspots in a faulty device?

44c after just a few seconds
With it's 60degree field of view, working close-up gives enough contrast to identify individual hotspots. One thing to notice is that the colour scheme is autoscaling. So "red" just means warmer than the surrounding area, not necessarity hot. The colors are spread over the range currently detected by the sensor. The good aspect is that it always gives the best contrast possible, the downside is, that it can be very irritating.

The microcontroller

The GD32 ARM Cortex-M3 Microcontroller

Quite a capable little 32-bit RISC microcontroller from GigaDevice's "Value Line". See the data sheet here for details. The GD32F130F4P6 is the simplest of the DG32F130Fx family in the TSSOP20 package, sporting 16kByte of flash memory.
This thing appears to be pretty much a clone of the STM32F103x4 and might well be programmable with a ST-Link programmer. (haven't tested that).
The earlier 1.1 version, for which Banggood has a schematic diagram available, had a STM32F103C8, which essentially has the same performance, but more (64KBytes) of flash memory. So they obviously cut costs here a little on their way to Version 5.1.2

Final words

At a price point around 50 EUR/USD, this is not only a great experimenter's gadget, but very useful to track down thermal problems. Certainly no match for a full blown thermal camera, possibly even with a visual overlay - the cheapest models starting at three times the cost of this device.
The 0-80C temperature range can also be a maior limitation, depending on the intended use.
For me it is way better than sniffing out hotspots on PCBs or burning my fingers on them.


Sunday, 15 November 2020

RF-Power8000 - Power meter installation on Windows 10

RF-Power8000 Installation

Get the software

I got my RF-Power8000 here from Bangood. Unfortunately they didn't provide a download link for the software and manual. A quick google search at the time (Nov.2020) of writing revealed this source:
  • Software download from passion-radio LINK
  • Instruction manual from passion-radio LINK
RF-Power8000


Install the driver

The RF8000 communicates over a USB-to-serial bridge, that your computer might not immediately find the right driver for. In that case, you'll find a "serial" device marked with a "?" in the device manager.
The driver is provided with the software package (see above). As I don't like drivers that come with a setup routine, I recommend to use the "rightclick/update driver" function of the device manager.
Just point it to the "drivers_usb_CH340" folder and windows will find and install the driver.
At that point you should see another serial port in the device manager:

The meter shows up on COM6



Register MSCOMM32.OCX

Depending on other installations on your PC, starting the RF8000 software with the uninventive name of "english.exe" might result in an error message. In that case, MSCOMM32.OCX needs to be registered on your system.
To register the OCX, open an "elevated shell" (right click the start button and choose "Windows Powershell (Administrator)")
There type (with the path pointing to your rg_8000 directory):
 .\regsvr32.exe C:\Users\admin\Desktop\RFPower8000\rf_8000\MSCOMM32.OCX

Your path will be different

Configure the software

The program "english.exe" needs to be configured for both the COM-Port and the Baud Rage. It defaults to COM1 and 4800. While with some luck, your COM-Port might be "1", the baud rate ist not correct. Also: in "Model selection" choose "RF-Power8000"
Here are the correct settings:
  • Model selection RF-Power8000 (F3)
  • Port number: set that to what your device manager shows as Com Port. In my case COM6
  • Baud Rate: 9600
After that, I have to press the center button to start the meter.

No, it ain't pretty :-(

To set the frequency and the attenuator value (you absolutely need an external attenuator!) for the measurement, hit the "spanner and screwdriver" button.

Addendum 20201116:
This russian (?) RC enthusiast has written his own software for the RF-Power8000

And it looks good, too:



Saturday, 16 May 2020

Tello Motor Repair done right!

How to change a Tello Ryze Drone motor

Other instructions on the web


Before attempting the repair, I checked the web for tutorials. But found most of them pretty terrible, usually causing permanent damage or ugliness to that nice drone.
All except one from DroneZone, which I only found after having finished the repair :-(

That is what a decent job looks like

Tools required

While not really a tool, you need a replacement motor. There are several sources on the web, but they come with small weirdnesses like gears or plugs. Like so often, I got mine from Banggood. They come in two wire lengths (71mm or 87mm), but as a wire can never be too long, I went for the 87mm, although I needed to replace a front motor, where the leads are shorter.
These motors are properly keyed, so you can't confuse the clockwise and counterclockwise motors.

Other than that, good quality precision screwdrivers are a must. Poor screwsrivers ruin the screws. I currently use both a Wowstick, and traditional hand tools, depending on the job at hand.
And of course the wonderful, regulated Mini TS80 soldering iron. The first USB iron that doesn't suck. It does not come cheap, but during the building renovations, when I had no lab space, I learned to love it and won't go back to my old Ersa iron.

Other household items include
  • a pin to peel off the gunk that seals the solder points
  • wire cutters / needle nose pliers
  • Tweezers are handy, too

Problems encountered

If you follow my video (see here), you will find that I struggled at a few points

Cracking the case open

The plastic is very thin, so go around the edges carefully with a spudger.

Removing the gunk over the solder pads

This was a pain. I tried several methods. What worked best in the end was to peel the silicone-like gunk off with a needle. No great fun.

Soldering

Desoldering needed more heat than I thought, given the delicate wires. That might have to do with the solder. I set the iron to 340 degrees centigrade. Later, when soldering the new wires to the board, the joints went dry immediately, so I replaced the solder. (Using solder wick)

Hotglue over the cable duct

Where the motor wire enters the body, there is a drop of hot-snot over the groove the wire runs it. This needs to be cleaned out.

Getting the motor out

That was not really hard. I could pull it out with my pliers, but the cable running through the motor holder gave quite a bit of resistance. So I smelled trouble getting the new wires in.
Motor arm

Putting the new motor in

The actual trouble is to get the new wires through the tiny hole in the motor arm. The trick is to bend the wires at an angle. You can see that in my video.

Final words

After the repair, I went through two freshly charged batteries. No problems. And other than in some repair videos, the drone does not look like it had been chewed up by a dog after the repair.


Friday, 15 May 2020

Benefits of using hardware encoding on an Intel HD 630 with ShotCut

CPU Power vs GPU for Video Processing

My prefered video editor
Shotcut Video Editor

Hardware

My Fujitsu Esprimo Q957 is more of an office PC than a Video editing, Coding, 
CAD or hardware experimenter's platform. But for the space it takes on my much-too-small desk, it does an amazing job in all of the above disciplines.
CPU-Z shows the GPU
So all in all, I didn't think the integrated GPU could help me getting the jobs done more quickly.

Encoding on the Intel HD Graphics 630

A near 15 minute video I currently work on, needed an unusually high number of modifications. Each with a lot of noise from the fans running at full speed.
100% CPU
This took nearly 8 minutes at an unpleasant noise level. Time to investigate alternatives...
Let's try that...
Involving the GPU is amazingly efficient. Less CPU usage and the GPU at a little over 50%, along with somewhat less noise.
CPU-wise this does not look like a massive difference, bit it is.
The best part: Videos now encode in half the time. Much better than what I had expected from an integrated "Office-PC" GPU.
Success! Less than half the time :-)

PS: Here is the link to Shotcut (free and open source)

PPS: To my amazement, the tiny Fujitsu desktop easily outperforms my relatively recent Surface Laptop 2. The benchmark only shows a little over 10% difference ( https://cpu.userbenchmark.com/Compare/Intel-Core-i5-8350U-vs-Intel-Core-i5-7500T/m388461vsm218898 ), but the system takes 6 minutes for the same job as above, even with the help of it's Intel HD 620. 

Friday, 14 February 2020

Verkonfigurierten USB Stick retten


Nach Experimenten mit einem Linux-Live System auf einem USB-Stick, erkannte Windows das Gerät nicht mehr ordentlich. Der grafische "diskmgr" brach an den entscheidenen Stellen mit Fehlermeldungen ab.

English version <here>

Hier die Vorgehensweise:
In Win10 die Administrative Shell starten (Rechtsklick auf das Windows-Logo, dann "Windows PowerShell (Administrator)" starten.
Dort "diskpart" aufrufen

DISKPART> list disk

  Datenträger ###  Status         Größe    Frei     Dyn  GPT
  ---------------  -------------  -------  -------  ---  ---
  Datenträger 0    Online          238 GB  1024 KB        *
  Datenträger 1    Online           29 GB  1024 KB

DISKPART> select disk 1

Datenträger 1 ist jetzt der gewählte Datenträger.

DISKPART> list disk

  Datenträger ###  Status         Größe    Frei     Dyn  GPT
  ---------------  -------------  -------  -------  ---  ---
  Datenträger 0    Online          238 GB  1024 KB        *
* Datenträger 1    Online           29 GB  1024 KB

DISKPART> clean

Der Datenträger wurde bereinigt.

DISKPART> create partition primary

Die angegebene Partition wurde erfolgreich erstellt.

DISKPART> active

Die aktuelle Partition wurde als aktiv markiert.

DISKPART> list part

  Partition ###  Typ               Größe    Offset
  -------------  ----------------  -------  -------
  Partition 1    Primär              29 GB  1024 KB

DISKPART>

Spätestens jetzt erscheint das Laufwerk mit einem Laufwerksbuchstaben im Explorer und kann wie gewohnt formatiert werden.

Achtung: Wählt man die falsche Disk, kann man sich leicht das System zerstören. Ein Vergleich der Ausgabe von "list disk" mit eingestecktem und abgezogenem USB-Stick hilft die richtige ID zu finden.

USB drive recovery after partitioning problems


This article once again is a "note so self" so I remember how to fix my thumbdrive after a screw-up experimenting with Linux;

In win 10 start "Windows Power Shell (Administrator)
Start "diskpart", then:

DISKPART> list disk

  Datenträger ###  Status         Größe    Frei     Dyn  GPT
  ---------------  -------------  -------  -------  ---  ---
  Datenträger 0    Online          238 GB  1024 KB        *
  Datenträger 1    Online           29 GB  1024 KB

DISKPART> select disk 1

Datenträger 1 ist jetzt der gewählte Datenträger.

DISKPART> list disk

  Datenträger ###  Status         Größe    Frei     Dyn  GPT
  ---------------  -------------  -------  -------  ---  ---
  Datenträger 0    Online          238 GB  1024 KB        *
* Datenträger 1    Online           29 GB  1024 KB

DISKPART> clean

Der Datenträger wurde bereinigt.

DISKPART> create partition primary

Die angegebene Partition wurde erfolgreich erstellt.

DISKPART> active

Die aktuelle Partition wurde als aktiv markiert.

DISKPART> list part

  Partition ###  Typ               Größe    Offset
  -------------  ----------------  -------  -------
  Partition 1    Primär              29 GB  1024 KB

DISKPART>

Looks good now. At this point the drive shows up in Windows File Explorer and can be formatted from there.



Friday, 24 January 2020

Testing a Bakeey microSD card

Is the Bakeey Extreme 64GByte any good?

The claims

Hard to see specs
The rough surface makes it hard to identify the markings. But as far as I can see, it claims to have the following characteristics:


  • 64 GByte capacity
  • Class 10
  • UHS: U3
  • Video Class: V30
  • Class A1
  • UHS1 (Bus Logo: I)
The question is: What does it all mean, and can I test that?




I bought the set (card/adapter/reader (usb-c / usb-a) here from Banggood.

I use h2testw to test the capacity and read/write speed. So from the results, I can see:
  • It really has the 64GBytes, so no fake that overwrites itself: OK
  • Class 10: I get a 13,4MByte/s write speed, so it meets the class 10 specs: OK
  • U3: With the supplied USB adapter, I could not get anywhere near 30MByte/s write speed. So for the moment the answer is: No!
  • V30: Again not with my adapter: No!
  • Class A1: That's 10MByte/s write speed and a low number of IOPS. So: Very likely OK
  • I logo: With the UHS-1 logo, the bus speed can be 12,5 to 104 MByte/s: Again likely OK
The read-speed I got was 17,4MByte/s with the supplied USB Card reader. Again not fantastic, but ok for a class 10.


EDIT: I re-tested with an USB3 card reader. The results were somewhat better:

  • 18.9MByte/s write rate
  • 31,6MByte/s read rate


I wanted to try 4k video streaming in my Olympus OM-D, but with the Micro-SD to SD adapter, the camera reported a card error. So I have no way to verify the 30MByte/s claim. But I have a compatibility issue with either the card or the adapter and the Olympus camera.
No issues in a Macbook Pro with the same adapter, though. Seems like a real compatibility issue.

Bottom line


For the card and the two adapters, I paid 10 USD. That appears fair for the set, but cards with similar specs are available from Transcend or Kingston in the same price range. An ok deal, but no need to rush. For my camera, I'll stick with a SanDisk Ultra that guarantees 40MByte/s for 4K recording.
All in all nothing to write home about.