Wednesday, December 6, 2023

Mailbag 2023 Q4-2

 Part 2 of my 2023 Q4 Mailbag post.
These are some other random items.

A non electronics item. Some gloves

This is a Male to Female USB C measurement device and has a small display.

Some more  USB items 

This for cooking, not for electronics. It is a bag with some special food paper inlays for our airfryer

Dupont cables

More (other) Dupont cables

Another non-electonics item.
Bags (i also got some other colors)

Connectors (4 pin audio) with cables

Chassis parts for the 4 pin audio connectors

Wire cutter(s) / scissors. I needed new ones as the one that i already had several years did not cut as good a before. Also for a special occasion i needed extra.

Voltage detector screwdrivers. For a special occasion i needed several of these. They do not only detect voltage. These modern ones (with a small battery) can also detect ground.
I want to also make a special blog post about these nice voltage detectors.

Sunday, December 3, 2023

Voltage tester - screw driver

This colorful screwdriver is not Dr Who's ultrasonic screwdriver, however it is still an interesting device. Already when i still was young i had screwdrivers with voltage testers. However his modern version can not only detect mains live but also the neutral !  

It is advertised as "Intelligent Voltage Tester Pen AC Non-contact Induction Test Pencil Voltmeter Power Detector Electrical Screwdriver Indicator" . (The price in Q4 2023 is around one euro ).
In contrast to the classic voltage tester they contain a battery,
Below some text and screenshots from the vendor website on AliExpress with the specifications ans explaining how to use this voltage tester/.


Battery model: LR41 X 3 (Included)
Measuring range: voltage 70-250V
Bit material: chrome vanadium steel
Shell material: ABS
Size: About 140x20mm/5.51x0.79in


1. High hardness and good electrical conductivity
2. Maintenance electrical measurement / screwdriver assist
3. Humanized clip design for easy electrical maintenance and portability
4. Fully insulated anti-fall material, durable and improved safety performance
5. Self-checking LED high-brightness bulbs: high-brightness works smoothly and is still clearly visible in the sun

Uses: can be used in electronic factories, electrical appliances, car maintenance, household, etc., widely used


1. Neutral line/live line detection: the test result LED red light and green light indicate live line, green light indicates neutral line
2. Detection along the line: LED light on means the line is unblocked, LED light off means the line is disconnected
3. Wire switch: if the plug and the inner core of the wire are intact, the light will be on, and if it is not on, it means that the core wire is in poor contact

Self check
N.B. : This is a screenshot. Not a video !
Neutral and Live detectionFinding breakpoints
Voltage range

(Discount price for 20 screwdrivers Euro 18,19 )

Thursday, November 30, 2023

Mailbag 2023 Q4-1

My last Mailbag post has been some time ago. This does not mean i did not get some new items. AliExpress had (and still has) promotions where you can order (minimum) 3 items for around 5.99 Euro. This gave an opportunity to get several items below 2 Euro.
Also some more expensive items where in my mailbag. I will split the backlog of my mailbag posts in several postings. Some postings are grouped around a topics so it will not be chronological. Also i will post some non electronic items. I will try to include some screenshots with prices. However price can change. Also sometimes what i actually payed is different (e.g. bundle discount). 

Small cheap shoulder bag.
It is a bit off topic, however as it is a nice cheap bag i decided to post this also on this mailbag bog post.

Two metal hobby knifes

Additional blades for the knifes (above)

This is a small cheap voice recorder with USB connector. It does not include memory, to use it an additional small SDcard is needed. The included internal LiPo battery can be charged via USB. Also the (not included) SDcard can be accessed. It has a small on/of switch to start and stop recording and also a status led. 

Waterproof (power) connectors. Don't know how waterproof they really are, however they where not expensive and look nice.

Some RF connectors ( BNC to SMA )

Two different sized telescopic antenna's. The long antenna was a bad buy. They are usable as antenna, however they are not very mechanical stable.  When using the long extended antenna the mechanical force became to big and it broke.  

Two PIR motion sensors

Monday, November 27, 2023

DigiPi -2-

Mosquitto / MQTT

One of my first experiments starting with DigiPi on my Raspberry Pi 4 was to install MQTT ( Mosquitto )  

sudo remount

sudo apt-get install mosquitto
sudo apr-get install mosquitto-clients

sudo systemctl enable mosquitto
sudo systemctl start mosquitto
sudo systemctl status mosquitto

The commands above gave no special problems. To using mosquitto over the network additional setup is needed. This protection only demonstrates attention to safety of DigiPi. 

mosquitto -v 

1700517586: mosquitto version 2.0.11 starting
1700517586: Using default config.
1700517586: Starting in local only mode. Connections will only be possible from clients running on this machine.
1700517586: Create a configuration file which defines a listener to allow remote access.
1700517586: For more details see
1700517586: Opening ipv4 listen socket on port 1883.
1700517586: Error: Address already in use
1700517586: Opening ipv6 listen socket on port 1883.
1700517586: Error: Address already in use

Local test

As (local) test i typed in a terminal screen (i used the browser terminal) to subscibe to mytest 

mosquitto_sub -d -t mytest

In another screen (for this i did log in using putty) i published "demo" to mytest

mosquitto_pub -d -t mytest -m "demo"

And got the expected response !
Perhaps i will later on use MQTT in combination with DireWolf
To use mosquitto over the network additional setup is needed. This protection only demonstrates attention to safety of DigiPi.

Saturday, November 25, 2023

DigiPi -1-


As i have a HAM licence I was looking for HAM software for my Raspberry Pi 4.
What often pops up is DireWolf, not the animal or the game!
DireWolf is  “Decoded Information from Radio Emissions for Windows Or Linux Fans”)  and was developed by John Lagner, WB2OSZ. As the name implies it can run on PC's and even a Raspberry Pi.
Also i found DigiPi ( ), the KM6LYW Radio DigiPi Project
DigiPi is a hot-spot for all amateur radio data modes, including APRS, ax.25, winlink email, ft8, js8cal, slowscanTV, PSK31, packet and even CW.  The implementation is an elegant, inexpensive, low-power, open-source Raspberry-Pi--based amateur radio data transceiver, managed exclusively by web browsers or smart-phone apps, with no bulky keyboards, monitors or complicated wiring.  At the website you can download an image for the raspberry pi with the options mentioned above already installed (including DireWolf and a web-interface.
DigiPiAt this moment (november 2023) the DigiPi image is behind a paywall, and the password is available to patrons on the KM6LYW Patreon Page. Anything gets you access to the DigiPi image, even a dollar. According to KM6LYW the point is not to keep the software locked up, but to ultimately throttle the  questions and support load.  Plus it gives priority access to design  decisions, code contributions and early releases. DigiPi is community driven  and open source.
I made a small contribution and could download the image and put it on an sd card for my Raspberry using BalenaEtcher. (Also other sdcard writing tools can be used.)
I did not yet connect a ham radio and wanted to experiment with the software on my Raspberry and am interested in DireWolf and a sdcard with DigiPi seemed a nice way to start.
Also (as i am just starting up my HAM activities) i do not have one of the many transceivers on a list, that can be connected directly via USB to the DigiPi, however it also possible to interface over audio.  For experimenting i recommend to plug in a USB audio device in the USB (perhaps in the beginning with nothing connected) as the software does sense if no interface is available and in that case it will not go to some options.

The installation

There is sufficient info available to make the system work, however i had some special wishes and also wanted to experiment.
I want the network connection running over the wired ether-net interface, not over Wifi. Also i like to run some other software (The Mosquitto MQTT server) and perhaps later interface this with DireWolf.
Therefore i connected an ether net cable to my LAN and booted the system.
The DHCP server of my home-network did give the IP to the ether-net connection of the system. (The IP address of the Wifi is managed by the DigiPi).
What i did and not every time will mention is that installed parts needs to be activated (by (re-)starting the service or a reboot of the Pi). So see this as a general guide not an exact list of commands that always will work for you!

Timeserver / nameserver problem

I noticed the date and time on my pi where not correct.
Over the wired network i could reach the system  (using hostname  "DigiPi" or the IP address)
I did try to configure ntp, however i did not find the configuration files.
I made the decision to install ntp using "sudo apt-get install ntp"
However i did not succeed as the nameserver was missing and sites on the internet could not be reached by name.
At the bottom of dnsmasq.conf is 

#craiger hotspot stuff

#AutoHotspot Config
#stop DNSmasq from using resolv.conf
#Interface to use

I changed changed no-resolv to #no-resolve and after this domainnames on internet could be resolved.

Now i could install ntp using "sudo apt-get install ntp" however i did not investigate the  system sufficient !! :
During ntp install i noticed removal of "chrony" and that is (a better) alternative for ntp.
I expect the time was not updated as the timeserver on internet could not be reached by chrony. So better not install ntp !
At this point i could go back and create a fresh sdcard and i am sure i will need to do that some time however
 "sudo apt-get install chrony"
gave me back chrony and i noticed the date and time where now correct.

Some links:

to be continued