posts on soldernerd

The Blog is Back

Fri, 17 Apr 2026 00:00:00 +0000

It’s been a while. The blog has been sitting there, largely unchanged, collecting dust and serving ads to anyone who happened to stumble across it. So I decided it was time for an overhaul.

Stepper Motor Controller Rev B

Wed, 01 Jan 2020 00:00:00 +0000

Looks almost like the first version

This board may look familiar to some of you. Because at first glance, it looks just like its older brother described here: Dividing Head Controller. But many things have been improved in Revision B.

Universal Interface

Mon, 16 Dec 2019 00:00:00 +0000

The Universal Interface

It’s time to present a relatively simple yet useful device: the Universal Interface. The need for this little helper arised when building the control for my CNC milling machine. But that’s a major project that I will introduce another time. Today it’s only about this little board.

Variable-Frequency Drive

Sun, 03 Feb 2019 00:00:00 +0000

I’ve just finished the variable-frequency drive (VFD) for my 1970s Schaublin 102 lathe. Before I dig into details, there’s a youtube video here:

Dividing Head Controller

Sun, 02 Dec 2018 00:00:00 +0000

This post ist about the CNC conversion of a manual dividing head aka indexing head. If you’re not familiar with that kind of equipment, there’s a wiki page here. One makes use of interchangeable indexing plates and and the internal worm gear to accurately divide the circle. Parts like cogwheels and the like can be machined this way. A video of the finished project can be found here on my youtube cannel.

USB Mass Storage Device Bootloader

Tue, 20 Nov 2018 00:00:00 +0000

Let’s start with a video. It will tell you most of what I’m going to write about today.

Solar Charger in Hackaday Prize Finals

Thu, 26 Jul 2018 00:00:00 +0000

I’m delighted to tell you that my MPPT Solar Charger has been nominated for this year’s Hackaday Prize Finals taking place on October 22nd. I’ve submitted it in the Power Harvesting Challenge (link no longer available) category a while ago and was just informed that it was picked as one out of twenty projects submitted to the finals. Check out the original article here. Of course, any support is highly appreciated.

MPPT Solar Charger - Revision F

Wed, 04 Jul 2018 00:00:00 +0000

While the solar charger was originally intended to be used as a standalone device, it can just as well be integrated into other projects. In such applications, the user interface can be left away without sacrificing functionality other than the display and rotary encoder.

Free Solar Charger PCBs

Wed, 27 Sep 2017 00:00:00 +0000

A reader of this blog was so kind to send me a number of surplus boards of two of my solar charger designs. Thank you, Joachim.

RaspberryPi Robot

Mon, 18 Sep 2017 00:00:00 +0000

It’s been almost two years since I did (or at least started) this project but I never sat down to document it. That’s what I want to do today. As the title says it’s about a little robot based on a RaspberryPi. Like many of its kind it is driven by a pair of stepper motors each driving a wheel directly attached to the respective motor axis. At the back there is another smaller, pivotable wheel to keep the robot in balance.

MPPT Solar Charger - Update

Mon, 11 Sep 2017 00:00:00 +0000

It’s been a while since I posted anything related to my MPPT Solar Charger project. That doesn’t mean that no progress has been made…

RX/TX Sequencer

Thu, 11 May 2017 00:00:00 +0000

Much like the beacon keyer presented here earlier, this RX/TX sequencer is a simple but useful little device. Its typical use is in ham radio applications when a separate power amplifier (PA) and/or a sensitive low-noise pre-amplifier (LNA) is used. Care has then to be take to safely transition between RX and TX states - and that’s where this sequencer comes in.

Programmable LED Dimmer

Sun, 30 Apr 2017 00:00:00 +0000

Around one and a half years ago I’ve designed and built various LED dimmers for both white and RGB LEDs. Then late last year someone approached me asking if I could make an RGB dimmer for him, too. But my designs were really tailored to their specific applications and built with home-made, i.e. milled PCBs which are time-consuming to make. So I decided to make a more universal version based on a proper, etched board which could be built in a small series and used for all kind of applications, both white and RGB. The result is this versatile, programmable 4-channel dimmer.

Beacon Keyer

Sun, 23 Apr 2017 00:00:00 +0000

This is likely the first ham radio related project that I document here on this blog. But my very first PIC project was a beacon keyer that I made for my father, HB9BBD. That was was in 2013. A beacon keyer is a great project to get started with microcontrollers since it’s not much more than a fancy way of blinking an LED.

MPPT Solar Charger Rev C - First Test Results

Sun, 02 Apr 2017 00:00:00 +0000

Over the last few weeks I have been quite busy with my MPPT Solar Charger project. I’ve built up a first board and started writing firmware for it. Since the last version was not too different in terms of hardware I was able to re-use most of that code. But I hadn’t even touched on the whole USB stuff back then so there was still a lot of work to do. While the project is still far from being complete I am happy to say that I’ve made quite some progress. Most importantly, the new design seems to work well and so far I haven’t found any mistakes in the board layout. But let’s go through this step by step.

MPPT Solar Charger Rev C Design

Wed, 22 Feb 2017 00:00:00 +0000

Over the last year or so I’ve designed, built and tested a standalone solar charger. It performed quite well but as with any complex design there were a number of things that needed to be improved. So I eventually reached the point where I decided to design a revised version. And this is what this post is all about.

C# USB HID Utility

Mon, 13 Feb 2017 00:00:00 +0000

Have you ever tried to write a program that connects to some device via USB? I have done so a few years ago and was shocked how much of a pain that is (at least on a Windows plattform). I always thought there should be a nice little library that wraps all those uggly DLL imports, marshalling and COM API calls and offers a nice and clean C# interface to the outside world.

Ultrasonic Anemometer Part 30: Downsized Hardware

Sun, 05 Feb 2017 00:00:00 +0000

In my last post of this series I’ve looked at different transducers and finally decided on a entirely waterproof 14mm model. The much lower signal level from those kind of transducers makes it necessary to reduce the distance between the transducers in order to still receive a reasonable signal amplitude. So I took my previous lasercut design and reduced it in size so that the distance between the transducers is only 120mm. I went to the local FabLab and and lasered two copies of the downsized design.

Standalone Inductance Meter on a Etched Board

Sun, 29 Jan 2017 00:00:00 +0000

In late 2014 and early 2015 I had posted a short series on an inductance meter project. The first post in that series described an Arduino shield that allowed an Arduino UNO to do inductance measurements and got this blog mentioned on dangerousprototypes.com for the very first time.

Ultrasonic Anemometer Part 29: Transducer Comparison

Fri, 23 Dec 2016 00:00:00 +0000

It’s been way too long since the last post in my Ultrasonic Anemometer series. But better late then never.

So far I have always used the same type of transducers. When I started this project I looked around and found the Multicomp MCUSD16A40S12RO. They were comparatively cheap and readily available so I ordered some and used nothing else for the next two or so years.

ReflowR on indiegogo.com

Fri, 25 Nov 2016 00:00:00 +0000

This will be my shortest post ever. But I just spotted a project on indiegogo.com that I think is worth mentioning: A small and affordable tool to do reflow soldering. It’s basically a heating plate specifically designed for reflow soldering. So it can reproduce JEDEC temperature profiles, it does data logging and and you can even control it via a web interface if you spend an extra 9$ on the wifi upgrade.

MPPT Solar Charger Testing II

Tue, 15 Nov 2016 00:00:00 +0000

It’s time to follow up on the MPPT Solar Charger project. Progress has been slow since I’m currently working full time and doing a master’s degree at the same time. Given that this blog has previously been something close to a 50% job at times things will necessarily slow down a bit. But all the projects, including this one and the ultrasonic anemometer are alive and well and I’m working on them whenever I find some time.

Low Power User Interface

Fri, 14 Oct 2016 00:00:00 +0000

As you may have noticed I’m quite busy working on the MPPT Solar Charger project. The latest version uses a 4 lines x 20 characters LCD that connects via I2C as well as a rotary encoder with a push button.

MPPT Solar Charger Testing

Wed, 28 Sep 2016 00:00:00 +0000

In a previous post I have presented a design for an MPPT Solar Charger. In the mean time I have built a prototype and also wrote some software for it. So today I’ll go through my findings of what works well and what needs to be improved. And yes, there are some flaws in the design…

Ultrasonic Anemometer Part 28: New hardware tested

Wed, 07 Sep 2016 00:00:00 +0000

I last time proudly presented the new RevB board and got a lot of feedback from people who want one, too. As mentioned I have all the components here to ship up to 10 kits but I was reluctant to send anything until I had the chance to do some hardware testing. Not much had changed since the last revision but I don’t like taking chances on things like this.

Ultrasonic Anemometer Part 27: Ready to take pre-orders

Sat, 03 Sep 2016 00:00:00 +0000

Good news: the boards from dirtypcbs.com have arrived and look great. I also got all the components for the 11 boards. Why 11? I ordered about 10 (they call it a protopack) and was lucky enough to get 11. Thats dirtypcbs.

MPPT Solar Charger Design

Sun, 28 Aug 2016 00:00:00 +0000

I’m currently waiting for the boards for my Ultrasonic Anemometer Rev B to arrive from Hong Kong and this gives me some time to write about the MPPT Solar Charger design that I did quite some time ago. I published a series of posts on a Arduino MPPT Solar Charger Shield and got a lot of encouraging feedback. But that shield was more of a proof-of-concept than a finished product. While it generally performed well it drew way too much current when idle to actually be deployed unless you can count on plenty of sunshine every day.

Ultrasonic Anemometer Part 26: Rev B Board ordered

Sat, 20 Aug 2016 00:00:00 +0000

I recently ordered my first PCB at dirtypcbs.com and the result was promising. So there was nothing stopping me from finalizing the Rev B of my standalone Ultrasonic Anemometer and ordering a protopack. I’ve placed the order a few days ago and expect the boards to arrive here in 2 to 3 weeks. This should be good news for all those of you who have been asking for kits and want to contribute to the further developement of this project. I’ll build up one or two boards as soon as they get here and do some testing. If everything works as planned I can order some more components and ship some kits soon after that.

Bi-Directional Voltage Level Translator - Board House Test

Mon, 15 Aug 2016 00:00:00 +0000

While most of my microcontroller designs run on 3.3 volts there is still the ocasional 5 volt design. Or I do something with an Arduino. So the need may arise to interface between logic working at different voltage levels. There are several ways of doing this, depending on your needs. Things are relatively simple as long as you know in advance which side is transmitting and which side is receiving. It gets more difficult if the communication is bi-directional or with busses such as I2C that are bi-directional by nature. I did a search on farnell.com and identified two chips that can translate between almost any two voltage levels bi-directionally. The Texas Instruments TXB0106 works with up to 6 CMOS (i.e. actively driven high or low) signals for protocols such as SPI. The PCA9306 (also from TI) is intended for protocols such as I2C that rely on pull-up resistors and where a line must never be actively driven high.

Ultrasonic Anemometer Part 25: I2C Interfacing and more

Thu, 11 Aug 2016 00:00:00 +0000

It’s been a long six weeks since my last post but that doesn’t mean that I haven’t done anything since. Among other things, I wrote some code to get the I2C interface working and hooked the anemometer up to an Arduino Uno with an LCD display attached. Apart from demonstrating the I2C interface this also nice for testing. For the first time I can see what this thing is measuring in real time without hooking it up to a PC over USB.

Ultrasonic Anemometer Part 24: New Microcontroller and Software Controlled Gain

Sun, 26 Jun 2016 00:00:00 +0000

It’s been almost three weeks since my last post and some further progress has been made. I’ve upgraded the microcontroller and can now control the gain of the second amplifier stage in software. But let’s look at the changes in some more detail.

Ultrasonic Anemometer Part 23: First successful measurements

Mon, 06 Jun 2016 00:00:00 +0000

In my last post I was happy to report that I managed to get the USB interface to work. This interface has since proved to be extremely valuable in software development and testing. While the device is taking measurements you can look at the results (or intermediate results) at your PC in real time. You can even log large amounts of data to a .csv file and inspect the results in Excel.

Ultrasonic Anemometer Part 22: USB up and running

Sat, 28 May 2016 00:00:00 +0000

Last time I showed you the nice new hardware of the new standalone ultrasonic anemometer. But at that time I had hardly any software written for it so I couldn’t do much with its 32 bit microcontroller. So the last two or three weeks I spend lots of time writing code that I’d like to share with you today.

Ultrasonic Anemometer Part 21: Standalone Anemometer Hardware

Sat, 14 May 2016 00:00:00 +0000

Last time I went through the design of my new standalone anemometer. Now it’s time to build this thing and see if it works as planned.

After I fried a couple of chips on my driver circuit testing board due to a wrong chip in the power supply I was a bit more careful this time and built up the board step by step.

Ultrasonic Anemometer Part 20: Standalone Anemometer Design

Wed, 11 May 2016 00:00:00 +0000

Last time I outlined my reasons to ‘go digital’ by adding a powerful on-board microcontroller and designing a standalone wind meter.

In the weeks that followed that decision I tried to find a suitable microcontroller and to design a prototype. Today I’ll show you the result of that work.

Ultrasonic Anemometer Part 19: Testing the Analog Circuit

Tue, 26 Apr 2016 00:00:00 +0000

In my last post I went through the design of the analog part of the ultrasonic anemometer. Today we will see how the circuit designed last time performs in practice.

Ultrasonic Anemometer Part 18: Analog Signal Processing

Tue, 19 Apr 2016 00:00:00 +0000

Recently, I’ve sucessfully tested the new driver ciruit for my ultrasonic anemometer. It performed even better than I expected and I will be happy to use it pretty much as it is.

Temperature Controlled Fan

Sat, 09 Apr 2016 00:00:00 +0000

I’m currently mainly working on my new anemometer design but once in a while I get distracted. For example when my Keysight E3645A lab power supply was making so much noise that I could hardly concentrate. That’s when the idea of this fan controller was born.

Ultrasonic Anemometer Part 17: Lasercut Mechanical Design

Wed, 06 Apr 2016 00:00:00 +0000

In my last two posts I have gone through my new anemometer circuit both in theory and practice. Click here for an overview over my ultrasonic anemometer project.

Ultrasonic Anemometer Part 16: Testing the new driver circuit

Thu, 31 Mar 2016 00:00:00 +0000

Last time I’ve presented my new design for the ultrasonic anemometer driver circuit. So now it’s time to see how it performs. If you’re new to this project you might want to check out the overview page or at least my last post.

Ultrasonic Anemometer Part 15: A new attempt

Tue, 22 Mar 2016 00:00:00 +0000

It’s been about one and a half years since I started out with my ultrasonic anemometer project. Like others before me I had to notice that this a much more demanding project than it appears to be at first. After countless hours of development and testing I have built this Arduino shield. It worked but the reliability of the measurements was never what I had aimed for. The problem was mainly how to figure out the absolute phase of the received signal. So the measurements were always precise - but sometimes off by a full wavelength. Then I was more or less inactive for most of 2015, mainly due to personal reasons. So the project was kind of stuck but i kept (and keep) getting a lot of encouraging feedback from you folks. I came up with new circuit ideas and decided to pretty much start with an entirely new design and to re-think each and every design choice I had made back then.

Keysight E36103A Lab Power Supply Review

Fri, 11 Mar 2016 00:00:00 +0000

I don’t usually do reviews but I just got a Keysight E36103A Lab Power Supply today and since it’s a newly released model there’s not much independent information out there so far. At least when I ordered mine 7 weeks ago I was unable to find a single proper review. So I thought I’ll share my first impressions.

PWM Dimmer for RGB LED

Sat, 05 Mar 2016 00:00:00 +0000

Finished RGB dimmer

In my last post I’ve described the design and construction of my LED dimmer project. This project here is similar but a bit more involved. It controls RGB LEDs so it can not only change the brightness but also the color of the light. Instead of a simple pot it used a pair of rotary encoders with push buttons. One controls the brightness, pushing its button turns the light on or off. The other changes the color, pushing its button toggles between color and white.

PWM Dimmer for LED Lighting

Fri, 19 Feb 2016 00:00:00 +0000

Finished LED dimmer

I have recently moved to a new apartment and was looking for a PWM dimmer to control some 12V LED strips. I thought that should be easy enough nowadays but it proved more difficult than I thought. All I found either didn’t meet my requirements, were uggly or expensive. So I decided to build my own, tailor-made to my needs.

Arduino MPPT Solar Charger Shield – Software

Fri, 12 Feb 2016 00:00:00 +0000

There have been two previous posts on this project: one on the concept and the hardware and one on hardware testing. You probably want to check them out first if you’re not yet familiar with this project. Or even better: Click here for an overview over this project.

Arduino MPPT Solar Charger Shield - Testing

Wed, 03 Feb 2016 00:00:00 +0000

First tests are being performed on the Solar Charger Shield

In my last post I’ve introduced a proof-of-concept Arduino solar charger shield. I went through the hardware as well as the way it works - or at least is intended to work. It was prominently linked on dangerousprototypes.com as well as some other sites and got quite a bit of publicity as a result. Thank you all for sharing this post.

Arduino MPPT Solar Charger Shield

Thu, 21 Jan 2016 00:00:00 +0000

A friend has approached me regarding his solar project. He wants to install a solar panel together with a battery and an inverter in order to have power at his allotment garden. He had looked at a hobbyist project where an arduino was used to build a MPPT (maximum point of power tracking) charge controller. I took a look at the design, liked a lot of what I saw and decided to build something similar.

USB Boost Converter

Tue, 04 Aug 2015 00:00:00 +0000

Finished 5V to 12V USB boost converter

I frequently need a low-power supply to run a microcontroller system. Typically, one uses a lab power for such purposes. But at least on the desk where I do the programming I don’t have one. Since these systems typically consume little current it would be handy to be able to power them from USB. Most of my devices have on-board regulators so the voltage is rather uncritical. For 3.3 volt devices, the 5V from USB is just right. But others have a 5V regulator so they need a higher supply voltage. And even others might even need 12 volts.

The Art of Electronics - Third Edition

Tue, 07 Apr 2015 00:00:00 +0000

The world has been waiting since 1989, now it’s finally here. The 3rd edition of the classic book The Art of Electronics by Paul Horowitz and Winfield Hill is finally out. My (Amazon.de pre-ordered) copy just arrived today.

Inductance Meter PCB goes to India

Sun, 08 Mar 2015 00:00:00 +0000

In a recent post I’ve offered a free PCB on a first-come first-served basis. I’ll be happy to mail the board together with some components to Mumbai, India tomorrow. It goes to Parth Sane, a student, homebrewer and soon-to-be ham radio operator.

Arduino Ultrasonic Anemometer Part 14: Wind Tunnel Testing

Mon, 16 Feb 2015 00:00:00 +0000

It’s been a while since I posted the last update on the anemometer project. The reason for this is that I’m struggling with the aerodynamical design.

By the way: Click here for an overview over the ultrasonic anemometer project: /projects/arduino-ultrasonic-anemometer/

Free Inductance Meter PCB - first come, first served

Sun, 15 Feb 2015 00:00:00 +0000

When I made the PCB for the stand-alone inductance meter, I erroneously used a SSOP footprint for the microcontroller (instead of the desired SOIC). The PIC is available in a SSOP package (PIC16F1963-I/SS instead of PIC16F1936-I/SO) but I didn’t have any at hand so I simply made a new board with a SOIC footprint.

Stand-alone Incuctance Meter Finished

Thu, 22 Jan 2015 00:00:00 +0000

If you’ve read my last post you’re already familiar with my Inductance Meter project: /posts/stand-alone-inductance-meter/. At that time the hardware was ready but there was no software yet. That’s been corrected, the inductance meter is now fully functional.

Stand-alone Inductance Meter

Tue, 13 Jan 2015 00:00:00 +0000

Some of you may have seen my arduino-based inductance meter in this post: /posts/arduino-based-inductance-meter/. The guys at dangerousprototypes.com picked it up (http://dangerousprototypes.com/2014/12/16/arduino-based-inductance-meter/) and this blog got more visitors than I could ever have imagined. Thanks, dangerousprototypes.

Arduino Ultrasonic Anemometer Part 13: Arduino library finally ready

Thu, 01 Jan 2015 00:00:00 +0000

It’s been a while since the last post of this series. As so often, the task turned out to be more demanding than I first thought. And then I was also entirely new to assembly language, got distracted by my Inductance Meter Project (/posts/arduino-based-inductance-meter/) and went on a skiing holiday. But finally, the promised library is ready.

Arduino-based Inductance Meter

Sun, 14 Dec 2014 00:00:00 +0000

Incuctance meter in action. It displays the resonance frequency together with the inductance

I’ve just finished a little Arduino project. It’s a shield for the Arduino Uno that lets you measure inductance. This is a functionality that I found missing in just about any digital multi meter. Yes, there are specialized LCR meters that let you measure inductance but they typically won’t measure voltages or currents. So I had to build my inductance meter myself.

Arduino Ultrasonic Anemometer Part 12: Working on an Arduino library

Wed, 03 Dec 2014 00:00:00 +0000

This is just a very brief update on what I’ve been working on the last few days. By now, this blog has caught up with where the project currently stands so the blog posts won’t be quite as frequent as they used to be. When I just started this series I had already worked on this my wind meter project for two months so I had plenty of material I only had to post.

Arduino Ultrasonic Anemometer Part 11: Testing the new hardware

Sun, 30 Nov 2014 00:00:00 +0000

Today I’ll go through each part of my new Arduino shield to see if it performs as expected.

If you’re new to my Arduino-based ultrasonic wind meter project, you might want to click here for an overview: /projects/arduino-ultrasonic-anemometer/

Arduino Ultrasonic Anemometer Part 10: Arduino Shield Ready

Thu, 27 Nov 2014 00:00:00 +0000

A world’s first: Ultrasonic Anemometer Shield for Arduino Uno

I’m happy to announce that my new Arduino wind meter shield is ready. I had posted the design as well as a photo or two of the naked board in my last post but now I’ve placed and soldered all the numerous components and it’s ready to go.

Arduino Ultrasonic Anemometer Part 9: A new hardware

Mon, 24 Nov 2014 00:00:00 +0000

My first wind meter prototype is kind of working. The software will need improvement to make this wind meter into something really useful. But both hardware and software are basically functional and can be built up upon.

Arduino Ultrasonic Anemometer Part 8: More Software

Sat, 22 Nov 2014 00:00:00 +0000

In my last post I talked about how to get the Arduino to output bursts of 40kHz pulses. Today I’ll go through the rest of the software so by the end of this post we’ll have a very rudimentary but working sketch for our ultrasonic wind meter.

Arduino Ultrasonic Anemometer Part 7: Basic software

Thu, 20 Nov 2014 00:00:00 +0000

Today I’ll tell you how I got started with my software. If you’re new to my blog you might want to click here for an overview over my arduino-based wind meter project: /projects/arduino-ultrasonic-anemometer/

Arduino Ultrasonic Anemometer Part 6: Mechanical design

Tue, 18 Nov 2014 00:00:00 +0000

If you’ve read through my previous posts of this series you know that here is an Arduino and two home-made PCBs together with 4 transducers waiting to work together as an ultrasonic wind meter. If you haven’t you may click here for an overview of posts on my anemometer project: /projects/arduino-ultrasonic-anemometer//posts/arduino-ultrasonic-anemometer-part-6-mechanical-design/

Arduino Ultrasonic Anemometer Part 5: Testing the digital board

Mon, 17 Nov 2014 00:00:00 +0000

In the last post I went through the analog board and showed what I had to do to get it working properly. Today I’ll do the same whith the digital board. Click here for an overview over this series of posts on the anemometer project: /projects/arduino-ultrasonic-anemometer/

Arduino Ultrasonic Anemometer Part 4: Testing the analog board

Sun, 16 Nov 2014 00:00:00 +0000

In this post I will go through the testing of the analog circuit and what I had to do to make it work properly. Click here for an overview over this series of posts on the anemometer project: /projects/arduino-ultrasonic-anemometer/

Arduino Ultrasonic Anemometer Part 3: Analog Circuit

Sat, 15 Nov 2014 00:00:00 +0000

Today I’ll go through the details of the analog cirquit. Click here for an overview over this series of posts on the anemometer project: /projects/arduino-ultrasonic-anemometer/

The analog board ready to be connected

This is what I would consider the heart of this wind meter. This is where the received signal is amplified and processed so the overall accuracy and reliability of the entire project really depends on it. The functionality of this board can be summarized as follows:

Arduino Ultrasonic Anemometer Part 2: Digital Circuit

Fri, 14 Nov 2014 00:00:00 +0000

I’m keeping my word and continue to document this project that I’ve been working on over the last two or so months. In this post I will talk about the digital part of the circuit.

Arduino Ultrasonic Anemometer Part 1: Getting started

Thu, 13 Nov 2014 00:00:00 +0000

This is the first of a series of posts to follow. I will describe my attempts to build an ultrasonic wind meter (anemometer) based on an Arduino Uno. By the time of writing, I have a working prototype but it will take me a while to catch up in this blog. So this is just the first post - more will follow soon.

Switch debouncing using 74HC14

Wed, 12 Nov 2014 00:00:00 +0000

This was one of the first PCBs I ever made myself as well my very first attempt at soldering SMD components. So if you were wondering why some of the copper on the right has not been removed - that’s why. At that time, I was not even using Eagle yet but some software called Sprint Layout. But this post is not really about this unimpressing board but about proper debouncing. Something I feel strongly about ;-)

Programming sockets for PIC microcontrollers

Tue, 11 Nov 2014 00:00:00 +0000

I regularly use PIC microcontrollers. I’ve tried some Atmel chips lately but I’m still by far most familiar with the PIC16 & PIC18 chip families. As you can see in my other posts, I tend to use SMD components but once in a while I need to program a DIP package.

Constant Current Dummy Load

Mon, 10 Nov 2014 00:00:00 +0000

This is a constant current dummy load. It’s controlled by a PIC16F1936 microcontroller. As you can see, it’s equipped with a 4x16 character LCD display and, less obvious, a rotary encoder with push button. It accurately sets the desired current via a 16bit DAC and reads both current and input voltage with a single-channel 16bit ADC each. Temperature is measured by the microcontroller’s internal 10bit ADC.

Simple, resistor based Dummy Load

Mon, 10 Nov 2014 00:00:00 +0000

Another afternoon project. Some time ago I was working on a 80 watts 12-to-36 Volts DC-DC boost converter. Not one of my most successful projects but anyway.

So I needed some kind of load but my home made constant current dummy load can only handle 20-something volts. A few 100 ohms 15 watt resistors were just what I needed. So I took 6 of them and made a simple, single-sided PCB that holds the resistors as well as 6 switches.

Variable Voltage Power Supply using a LM317

Mon, 10 Nov 2014 00:00:00 +0000

A classic afternoon project. I was in need of a variable voltage and didn’t have a proper lab power supply available. But I did have a solid 12 volts from an old computer PSU. So I built myself this little thing.

Xilinx Prototyping Board

Mon, 10 Nov 2014 00:00:00 +0000

Some time ago I wanted to try out programming CPLDs in VHDL. I was entirely new to both of those topics and I didn’t have a real need for a CPLD at the time. So I built myself a nice little prototyping board for the Xilinx XC9500XL complete with some push buttons, LEDs a 7-segment display and a PIC16F688 used mainly as a clock source.