110v temperature controlled soldering station build no. 2


Mike Doughty from PCB Smoke shared his DIY 110v temperature controlled soldering station in the project log forum:

This project is build number 2 of a 110v temperature controlled soldering station. It is a follow-up post to the project that I was working on last October.
Blog post with complete details here.
This version has a couple of improvements over the first build. This new soldering iron is a better unit and was less expensive than the first one.
A chisel tip plus a selection of other tips was available for this soldering iron instead of being limited to a conical tip only.

More details at PCB Smoke project page.

Via the forum.

Check out the video after the break.

USB curve tracer for NPN transistors


Dilshan Jayakody documented his USB port base NPN transistor curve tracer project:

Curve tracer is an electronic test instrument to analyze the characteristics of transistors and other discrete semiconductors. In this post we construct USB base curve tracer to analyze properties of NPN transistors. This curve tracer is build around Microchip’s PIC18F4550 MCU and it use simple Windows based GUI application to plot captured data of a transistor.
In this design PIC18F4550 MCU is used to establish USB connectivity, perform voltage readings and control current/voltage flow into the test subject. To minimize the cost and to make it simple, we use R2R ladder circuit to generate discrete collector-emitter voltage levels for the transistor on test. In each scan session collector-emitter voltage level get increase from 0V to 7.5V in 256 steps. In this design, “tracer” scans the transistor for 7 base current levels which are in between 7µA to 60µA. In viewer application collector-emitter voltage levels are plotted on x-axis and collector current is plotted on y-axis.

More details at Dilshan Jayakody’s blog.

Project files available at sourceforge.net.

App note: The LED versus LCD decision


Choosing between two display types, LED and LCD discussed in this application note from Murata. Link here (PDF)

Users of contemporary digital panel meters (DPMs) have a variety of options available to them. While options are nice, they invariably mean more choices have to be made. After determining what meter resolution one requires, the next most basic decision is usually which type of display to use liquid crystal or light emitting diode?
Traditionally, liquid crystal displays (LCDs) have been the obvious choice for outdoor/daylight applications and/or for applications requiring extremely low power consumption (current drains less than 15mA). Light emitting diode (LED) displays, with their comparatively low light intensities and relatively high current drains, have been excluded from these more demanding applications.
Recent DATEL innovations, most notably the introduction of extremely low-power LED displays, have complicated the once straightforward, LED/LCD decision.

App note: EFM32 Energy Modes


Application note from Silicon Labs on their EFM32 energy saving microcontrollers, some interesting points are discussed how these type of microcontrollers can conserve power. Link here (PDF)

In battery powered microcontroller applications, energy saving is essential. By reducing the current consumption, the mean time between battery charging / replacement can be significantly increased. Following these principles will drastically reduce the current consumption:
• Use appropriate Energy Modes
• Exploit low energy peripherals
• Turn off unused modules / peripherals
• Disable clocks to unused modules / peripherals
• Reduce clock frequency
• Lower the operating voltage
The EFM32 supports extensive usage of all these principles.


Radionova 1 frequency synthesizer


Vasily Ivanenko has written up documentation on his Radionova 1 frequency synthesizer project:

Frequency synthesizer for my Jupiter receiver — Радионова 1 — [ Radionova 1 ]
Greetings! Most of my future homebrew radio projects will focus on building radio astronomy gear.
Radio astronomy offers much fun + learning for the radio homebuilder — example topics include how to design and make antennas, LNAs, receivers, and frequency synthesizers from HF to microwave. Further we may craft op-amp analog integrators to remove background noise, and/or ADCs, plus write software to store and analyze our data. Avid radio astronomers enjoy a strong understanding of noise measurement/physics, plus a whole lot of really cool science. I’ve already made new friends and feel inspired by the dedicated, skillful folks who listen to signals from space on stuff they craft in their home labs. In radio astronomy, Dx might mean receiving signals from 590 million kilometers away. I’m in!

Project info at QRP HomeBuilder blog.

Slider controller with auto-reverse and variable speed control


Paulo built a DIY electronic camera slider controller based on a small PIC microcontroller. It supports auto-reverse and variable speed:

These motorized sliders share a common electronic controller design that provides speed control for the gear motor and also an auto-reverse feature using limit switches. In this article , I’ll go over the electronics and software for this slider controller and show how you can build your own.

Project info at paulorenato.com.

Check out the video after the break.

Force FTDI FT232 USB to serial converters to use a single Windows COM port

Ever notice that each new FT232 inserted into each USB port is assigned a unique COM port number under Windows? When we’re developing hardware with lots of prototypes flying around Windows quickly hits COM 100. Each FT232 has a unique serial number and the driver creates a new COM port for each by default.

FTDI has a quick knowledge base item  about editing a registry key to disable this and stick with a single COM number.

“For a default FTDI device ID (VID 0x0403, PID 0x6001), add the following registry REG_BINARY value set to 01:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlUsbFlagsIgnoreHWSerNum04036001 ”

It’s not difficult to do, but it is impossible to find with Bing* so we’re posting it here for reference.

*Bing is the most reachable English search engine in China at the moment, though reachable doesn’t infer quality search results.

Reverse engineering the popular 555 timer chip (CMOS version)


Ken Shirriff wrote an article on reverse engineering a 555 timer chip,  He writes:

This article explains how the LMC555 timer chip works, from the tiny transistors and resistors on the silicon chip, to the functional units such as comparators and current mirrors that make it work. The popular 555 timer integrated circuit is said to be the world’s best-selling integrated circuit with billions sold since it was designed in 1970 by analog IC wizard Hans Camenzind[1]. The LMC555 is a low-power CMOS version of the 555; instead of the bipolar transistors in the classic 555 (which I described earlier), the CMOS chip is built from low-power MOS transistors. The LMC555 chip can be understood by carefully examining the die photo.

Details at Ken Shirriff’s blog.