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

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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 OpenHardware.co.za.

A 7400 frequency counter, on perfboard

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jaeblog published a new build:

I like perfboard, especially the ones with plated trough holes. But I also like SMD components, and more and more fun IC’s are not available in DIP. So a while ago I designed some perfboard with 1.27mm pitch, making some SMD parts like SOIC stuff easy to prototype on it, and also mix THT and SMD stuff.
Looking for a nice little project to build on it, I came across a frequency counter made with 7400 logic, perhaps not the most efficient approach, but a fun one at that. I made a few changed to the design, partly because of some components I already had like the 74HC160 and 4543 (yes, not 7400 but still logic :P) and partly to improve on the design, for example by adding a 10Mhz oscillator instead of a NE555 as the clock source. The current end result looks like this, a case is ordered and a follow up post will be made when the project is nicely tucked away in a case.

More details on Just another electronics blog.

Traktorino, an open source DIY MIDI controller

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Here’s an Arduino based open source MIDI controller by Musico Nerd, the Traktorino:

The Traktorino is a powerful low-cost DIY MIDI Controller. It is based in the Arduino platform and it comes in DIY kit, or assembled. In its core, there’s a shield that connects to an Arduino Uno, which uses open-source code, making it totally hackable.
The Traktorino is a MIDI class compliant device, designed for controlling Traktor. It has several features and custom made mappings, so you can take the most of the software. However, it can do much more than that. The Traktorino can control any software that accepts MIDI, like Ableton Live, Serato, FL Studio, Logic, etc

More info at musiconerd.com and on GitHub.

Check out the video after the break.

Automatic fan controller for server racks

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Dilshan Jayakody published a new build:

In this post we describe fan controller which we designed for our 9U wall mount server cabinet. This fan controller is designed to drive a 12V DC cooler fan with pre-configured intervals or by monitoring the temperature of the server cabinet.
Core components of this fan controller is CD4060 binary counter, LM35 temperature sensor and LM358 operational amplifier. In this design CD4060 is used as long duration timer and it can configured to trigger cooler fan from 1-minute and up to 4-hour.

See the full post on his blog here.

10MHz distribution amplifier

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G4FRE built a 10MHz distribution amplifier:

I have had a need for a distribution amplifier for a while now. Searching around I found the design by G4JNT in Radcom, which filled my needs. I redrew the circuit for 4 outputs and had PCBs made. (if you want one contact me!)  I now have the units in my M1DST 10MHz Thunderbolt monitoring project and in my LPRO101 10MHz Rubidium source.

See the full post on his blog here.

Low cost single cell battery pack simulator

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Mare writes:

There are many battery cell simulators available which could simulate battery cell(s). Unfortunately, none is emulating any of the digital protocols used by fuel gauge devices. Optimal solution to efficiently emulate given smart battery pack is to use custom solution based on battery cell simulator and fuel gauge protocol emulator. Both parts could be fused together in small, but efficient smart battery pack emulator.

  • complete battery cell simulation
  • fast response time
  • unlimited cycle use
  • flexible fuel gauge protocol emulation
  • use of a standard interface for integration in automated test equipment

More details at Mare & Gal Electronics homepage.