The K7TMG HF Morse code temperature beacon


AA7EE published a new build, a little temperature beacon:

This was a fun little project – and it gave me an idea for a future one. Sometimes, I find that the more complex undertakings, which require more planning, can get to the point that they “take me over” somewhat. At that point, for me, some of the fun starts getting squeezed out and that, of course, absolutely cannot be allowed to happen. This is the time when simple and fun projects save the day.

Check out the video after the break.

See the full post at Dave Richards AA7EE blog.

NickelBot – Laser controller


bdring made this laser controller for his wooden nickel engraver project and wrote a post on his blog detailing its assembly:

Here are some details on the custom laser controller I made for the NickelBot, wooden nickel engraving machine.
I want to use Grbl to control the machine. Grbl has support for lasers that allows better power control during the engrave. It also has the Core XY support I need for the H-bot mechanism it uses. The only feature I needed that it did not have is a hobby servo output.

More details at Buildlog.Net blog.

App note: High-speed lithium-ion battery charger


C8051F300 implementation of Li-Ion battery charger from Silicon Labs. Link here (PDF)

Driven by the need for untethered mobility and ease of use, many systems rely on rechargeable batteries as their primary power source. The battery charger is typically implemented using a fixedfunction IC to control the charging current/voltage profile.

The C8051F300 family provides a flexible alternative to fixed-function linear battery chargers. This note discusses how to use the C8051F300 device in Li-Ion battery charger applications. The Li-Ion charging algorithms can be easily adapted to other battery chemistries.

AtPack: Atmel Pack parser, visualizer and fuse calculator



AtPack – Atmel Pack parser, visualizer and fuse calculator from Vagrearg:

Looking for an up-to-date fuse-calculator for the Atmel(*) AVR chips has been something of a long search. There are several online versions, but they have not been updated to the new chips (like the ATmega328PB).
When you have got an itch, you simply scratch it… Don’t you?
Well, I did, and it resulted in an analysis of the Atmel Pack format, which can be freely downloaded under an Apache 2.0 license. The AtPacks contain a master XML file with device lists and links to each device’s XML file, which in turn describes the entire chip. The format is not that hard to understand and can be easily mangled into something useful. Then, some crude jQuery hacking and many hours later… you know how that works.

Code is at GitHub and there is an online version.

Via Vagrearg.

Lipo charge/boost/protect board in 18650 cell holder format


Peter6960 published a new build:

So couple months ago, GreatScott made a video where he designed a circuit. Nothing too innovative, just the same TP4056 charger the MT3608 Boost combined on one PCB. He did add a Lipo protection circuit though, initially using the same DW01. But then, the Aha moment from this video, he found a footprint compatible IC the FS312F-G – which is set at 2.9v! Way healthier for your cell’s longevity!
First of all I had to redraw all his work in Eagle (As I wont be using a cloud based service like EasyEDA for obvious reasons) and then order the PCBs. I added two boost circuits since I had the board space, as I can imagine needing dual voltages at some point (for example if that reverse LCD needed 12v and the Pi needed 5v – i could run both off one board.

Project info at

App note: Preventing LED failures caused by corrosive material


Chemical compatibility of LEDs application note from OSRAM. Link here (PDF)

The performance and stability of light emitting diodes (LEDs) may be influenced by various chemical incompatibilities arising from chemicals and materials used, amongst other things, in luminaire construction, or by gases in the proximate environment of LEDs during field operation. Nevertheless, LEDs have to fulfill a wide range of customer needs and requirements in indoor and outdoor applications.

This application note provides information about the chemical compatibility of certain substances with LEDs, particularly with regard to some of their basic components. In this context, the main mechanisms of chemical incompatibility are illustrated using examples of blue and white LEDs.