I released MG-log version 0.6 to Google Play store this week. It is now a quite practical app. I made my own log for Android, because I could not find a QSO logging app that would be easy to use during portable operation and not cluttered. A log for me must be build of several text fields, a decent database backend and some GUI-glue. Logging should be as easy as typing the callsign, report, optionally QTH, some remarks and pressing enter at the end.
Continue reading “MG-log 0.6 for Android”
My work computer is a Windows machine running several virtual machines with Linux and FreeBSD via VirtualBox. A part of my work requires developing software that interacts with hardware. Most of the time I have successfully used VirtualBox USB filtering to redirect USB devices to the virtual machines, but recently I got a USB device (CDC-ACM class) that refused to be forwarded to the VM.
Continue reading “Serial port redirection from Windows to Linux with socat”
I like to use Gentoo for most of my tasks (except the smallest systems that run OpenWrt). I also wanted to have it on the Banana Pi. I did not find any specific manual for Gentoo and the Banana, so I followed the standard, two-step installation manual for any architecture:
- Extract a stage 3 tarball to the medium that will be the rootfs
- Try booting the kernel into it
Continue reading “Gentoo on Banana Pi”
RRDtool is both a database and a graphing tool that is well-suited to visualize time-varying data like temperature, pressure and all kinds of telemetry.
There are many tutorials available, but they dig too much into the details (like the official one). Since I use RRDtool only for storing and graphing telemetry data I will explain how to do it the easy way.
I use RRDtool for graphing many sources of data, like my small solar system:
Continue reading “RRDtool – quick tutorial”
The Banana Pi is a great alternative to the well-known Raspberry Pi. It is not a clone, nor a knock-off, rather a completely different, open single-board computer of a very similar size and good price. Most important features (compared to Raspi) to me are the 3 UARTs (one for the serial console, two free eg. for a GPS, the Raspi has only one in total) and a power management chip with battery charger.
Continue reading “Banana Pi on battery power”
I have recently bought a BananaPi with the intent of making a automotive datalogger. I needed a simple power supply that would work reliably in my car. I found some nice looking modules in “The Thick Electronic” store on Aliexpress.
Continue reading “Small, cheap power supply modules from Aliexpress”
This is one of my older projects. I designed it for a friend of mine when he became fed up with his Rot1prog controller going bonkers all the time. I wanted it to be something as simple as possible, but still doing its job, easy to use and easy to service.
Continue reading “Universal antenna rotator controller”
I finally completed work on my networked thermometer. I got some old 7Ah 5-cell NiCd battery packs from emergency lighting fixtures that will power the device. I wonder how long can they last. NiCd batteries suffer from high self-discharge rates, on the other hand the NodeMCU will sleep most of the time and use very little energy.
Continue reading “NodeMCU as a standalone thermometer”
I recently got some discarded NiCd batteries from emergency lighting fixtures (5 cells, 7 Ah) and I started looking for a way to check if they might still work. While searching for chargers I found model B6AC that: charges automatically almost any battery chemistry (various lithium, NiCd, NiMH, lead-acid), can discharge batteries in a controlled way, balance li-ion battery cells, can cycle the battery through several charges and discharges, indicates the charge and discharge capacity (and probably some more features I still do not realize).
Continue reading “B6AC battery charger teardown”
In the last post I made a short introduction on development using the NodeMCU platform with a simple reading of a 1-wire thermometer. This time I will show how to make a basic networked application for the NodeMCU and the server part for a computer to gather some useful data.
The idea is pretty simple: do a temperature conversion, connect to a wireless network, transmit the reading to a server, maybe get back some configuration and start over.
Continue reading “NodeMCU networked thermometer”