Reload Controller header image

Reload Controller

Earlier this year I purchased an Arachnid Labs Re:load Pro, which is an adjustable constant-current load. I’ve always wanted an electronic load for my lab, but didn’t want the spend the money. The Re:load Pro solved that problem as it’s just $125. Sure, it doesn’t sink as much current or have all the options of fancier units, but it does everything I need. For testing panel meters, batteries and LEDs, it’s quite capable. So far, I’m happy.

Reload Controller Main screenOne of the features that caught my interest when I purchased it was the ability to interact with it via a virtual serial port on the USB interface. I immediately got the idea to develop an application that could control a Re:load Pro, but didn’t have time to work on it. Recently however, I started working on serial port projects at work again, and I finally completed my serial port class, called dsub. I needed to test it, and I thought of the Re:load Pro. It was a perfect device for testing. I set about developing an app, and correcting some bugs in dsub along the way. The result is an improved dsub class, and a small application called Reload Controller which I’m releasing here. (more…)

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dsub: Serial Port class for C#.Net

dsub main formI’ve long held an affinity for serial ports. They’re easy to understand, easy to setup, and require no special drivers. I’ve worked on several projects over the years that have utilized serial ports, mostly in classic VB applications. Since learning Microsoft C#.Net, I’ve wanted to use it to interface with them. A few years ago I picked up a copy of Serial Port Complete Second Edition by Jan Axelson, and it’s been a tremendous help. Much of what I’ve learned has come from her book and website. I set out to develop my own serial port class based on my needs, and I’ve now finally finished it to the point where I feel comfortable sharing it. It’s called dsub, named for the D-subminiature electrical connector. I’m releasing it under an MIT license so you can download, use and modify the application and source code.

Download dsub here (Visual Studio 2010 project)

dsub uses .Net’s built-in SerialPort class, but adds some additional functionality to deal with multi-threading, error handling, etc. I won’t cover all the details of how it works, or why; for that, you should pick up a copy of Jan’s book and check out the COM_Port_Terminal application available on her website. dsub does differs in several ways from her serial port class, the most important difference being that I use the SerialPort.ReadLine method to get new data from the buffer. As a result, any serial port data that dsub reads will need a defined “end of transmission” character, such as a carriage return or line feed. This can be specified in dsub, so it’s possible to use any character. I did this because all the equipment I deal with sends data this way, and it’s easier to parse the data once I know the transmission is complete. If you have a situation where there isn’t a defined end of transmission character, then dsub won’t work. (Note: Jan’s class does not have this limitation.)

dsub Settings FormThe GUI application that’s included will read data from the selected serial port and display it in a grid. If a field delimiter is specified, it will use that to break up the data into separate columns in the grid. At the bottom of the screen, you can enter text to be sent. There is also a textbox where errors will be displayed. The application implements all the features of dsub so it provides a good example of how to use it.

If you use dsub in your application, let me know! I’d love to hear how it’s being used. I’ll also do my best to answer any questions or address any issues with it.

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Update: Memory usage reporting fixed in Analog PC Stats application

Updated PC Meter application

It was brought to my attention a couple months ago by mnedix that the application I developed for the Analog PC Stats Meter was not reporting the correction Memory usage. I looked into it, and it turns out that the PerformanceCounter I was using in C# ties into the page file, not just physical memory. Apparently it was close enough to the physical memory used when I tested the program initially, because I never caught it. I just released an updated version of the application today that get the actual physical memory percentage used (you can download it here). It utilizes the GetPerformanceInfo Windows API to do this, using code developed by Antonio Bakula. This post at Stack Overflow is what led me to his solution. As the screenshot above shows, it’s now very close to what Windows reports. It’s a little off, maybe due to rounding, I didn’t have a lot of time to dig deeper. It’s close enough, at least for me! In the screenshot, I’ve got a couple textboxes that display physical available memory and total physical memory for troubleshooting.

While I’m posting, I want to point out it’s been approximately a year since I last posted on my blog, but I’m still here. The last year-and-a-half has been quite hectic for me, but I hope to get back into working on projects and sharing them on here soon! I’ve heard from a few people who have enjoyed my posts and used the information I’ve shared to work on their own projects and it’s been great hearing from them. Thanks!

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Manakins header

Vintage Fold-Out Anatomical Diagrams

Manakins - femaleI stopped at an estate sale over the weekend that was taking place just down the street from where I live. I didn’t have anything in particular I wanted to find, so I waited until it was nearly over to see if I could strike some deals. I went in about two hours before it was set to close, and I immediately spotted these vintage anatomical charts being offered for $10. I told the woman it was just weird enough for me to want to buy but… and before I could finish she offered to make it $5 and I was sold. I didn’t even get a good look at them until I got home, but when I did I quickly found it was a great purchase.

Manakins - maleThese charts were originally a supplement to The New Modern Home Physician, which from the little bit I’ve gathered was an encyclopedic home medical reference first offered in 1934 (then called The Modern Home Physician.) I’m not sure when these charts were produced; one listing I saw for them indicated the 1950’s, but I haven’t found a solid reference to back that up. The envelope refers to the charts as “Manakins”, and they feature different layers of the human anatomy that are able to be removed or folded out to reveal different parts of the body. There is one male and one female. Some of the organs fold out individually to reveal other organ that are otherwise obstructed. All in all, they’re very interesting and beautiful charts with a great vintage charm.

Manakins - UterusOne thing I find interesting is how the sexual organs have been censored, and when I say censored, I mean they’re completely ignored. The male is illustrated with a towel wrapped around his waist, and none of his sexual organs are shown, not even in the internal diagrams. The female is shown fully naked, however she has no vulva, and again, none of the sexual organs are shown in any of the internal diagrams. Despite all of this, the female is pregnant, as her uterus contains a fetus (how she became pregnant then is unclear.) I find it odd that such otherwise wonderfully detailed diagrams do not include such an important aspect of our human anatomy, but given the probable era(s) these were produced and the fact that they were targeted at the home market rather then professionals, it may have been considered the proper thing to do then. To me, it seems rather prudish, but then nowadays all of this information is available in explicit detail on the Internet.

I’ve got more photos/scans of the diagrams after the break, and higher-res copies on flickr. If you know anything more about these, please share! I’ve ordered a copy of the book as it sounds interesting as well.

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Crate built from upcycled pallet wood

Crate built from reclaimed pallet woodI recently inherited several tools and and pieces of equipment which I hope to put to good use someday. For now though, I live in an apartment, which means much of this stuff is going into storage. Some of the equipment is heavy and prone to damage, so I need a way to protect it. I decided to to build some small crates for these items, since cardboard boxes won’t be strong enough. However, I don’t want to spend a lot of money doing it, and lumber is expensive, so I figured I’d get what I need from old pallets. They’re a popular source of upcycled wood for DIY projects, which means there’s lots of info on how to reuse them, and best of all, they’re free. Last weekend I set about transforming some old pallets into crates and I’m quite happy with the results.

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Objective2 Headphone Amp

I love headphones. It’s the only way I can listen to music much of the time; without them I wouldn’t be able to. At work I listen on Grado SR-80’s, which allow external sound to come through so I can still hear my phone ring and be aware of what’s happening around me. At home, I wear closed phones like my Ultrasone HFI-580’s so I don’t have to hear what’s happening around me, allowing me to enjoy my music and movies in peace. With all of this headphone listening, it was inevitable that I would eventually take an interest in headphone amplifiers, and I did. Recently, I built the Objective2 headphone amplifier (actually, I built two – for home and work) and in this article I’ll cover what led me to the Objective2 amp and my experience building it.

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Install ntop on Ubuntu/Linux Mint

ntop graphIn a previous post, I wrote about how I setup a transparent bridge computer, which is able to monitor all network traffic passed through it. It works great, but to make it really useful, it needs some software that can report on the monitored network traffic in a useful manner. I decided to use ntop for this purpose, as it provides powerful reporting on bandwidth usage, which is exactly what I’m after. I’m not a regular Linux user, so I usually take the easy approach and install software through whatever GUI-based software manager is included. When I did this in Linux Mint however, I found the version available was not the latest, which is 5.0.1. I also learned that ntop has since been replaced by ntopng, which wasn’t available through the GUI. I’ve had some college courses in Linux/Unix administration, so I figured I could handle installing it “the hard way”. In this post, I’ll cover how I got ntop 5.0.1 running on my bridge computer.

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Creating a Transparent Bridge with Linux

Two Ethernet cablesI recently became interested in getting a better handle on bandwidth usage on our Internet connection at work. I wanted to see what I can do for free (or at least very cheap) so I started researching solutions using Linux. Before I can try out any software though, I need a computer that can do the monitoring. I decided to build a transparent bridge or “Machine-In-The-Middle”, which is a computer with two network interface cards (NICs) which are bridged together so that any traffic going to one card is passed through to the other. The bridge computer is installed in between two other nodes on the network, and any traffic passed through the bridged NICs can be monitored by the bridge computer. The bridge creates a slight delay, but is otherwise transparent to the nodes it is connected to.

Most of the information I used to guide me in setting this up came from Bridging Ethernet Connections at the Ubuntu community wiki and this page on how to setup a bridge in Debian from microHOWTO. I thought it might be pretty difficult, especially since I’m not a hardcore Linux guy, but I found it to be surprisingly easy. For the rest of this post, I’ll cover what I did to setup my transparent bridge computer.

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Infrared Pulse Sensor

IR pulse sensor and oscilloscopeLast week, I bought something I’ve wanted for quite some time: an oscilloscope. I’ve been doing more projects where a scope would be useful, such as audio amplifiers, PWM, and AC-DC rectification. And besides that, oscilloscopes are just plain cool. Of course, a scope by itself isn’t much fun, it needs something to measure. Something like an AC sine-wave, or an audio signal, or maybe… a person’s pulse rate? It’s possible, with the right sensor. Sean Michael Regan shows us how in the latest MAKE Weekend Project. I knew right away that it was perfect for trying out my scope. It was a bit of work, primarily because I modified the circuit, but the finished sensor is a lot of fun, and there is a lot of potential for doing more with it.

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cigarMoy Headphone Amp

cigarMoy FrontI built my first cMoy earlier this year, and it came out really great for my first attempt at building a headphone amp. The only problem was that it’s a poor match for the headphones I use.  My headphones are all efficient low-impedance models (Grado, Ultrasone) that don’t require a lot of voltage. What they need is more current. The basic cMoy design doesn’t provide this, at least not with the OPA2132A OpAmp. I soon learned though that several DIYers have built similar “cMoy-esque” amps based on the circuit used in Grado’s RA1 headphone amplifier, which uses an NJM4556 (aka JRC4556) OpAmp, good for 70ma of current per channel. I decided to try building one, and I wanted it to be a little different.  So I built it in a cigar box.cigarMoy inside

There was quite a bit of drilling and cutting involved, and I destroyed a couple boxes in the process. The volume knob is installed where the cigar maker’s medallion was previously located, which had their logo. For the circuit, I took some ideas from both the cMoy and the RA1 clones. I used some pretty high-end hardware, such as the Neutrik locking 1/4″ jack. It wasn’t because I thought it was necessary, but because it was easy to mount to the cigar box.

cigarMoy backThe result? Not very good. It’s unique, and looks interesting, but it doesn’t work very well. I ended up building two of them, and both are very noisy. Copper shielding on the second build helped, but not a lot. It might be all of the wiring needed to connect everything, or just the result of a poorly engineered DIY project based around a potentially “cranky” OpAmp, but it just isn’t a great amp. So I’ve kept the second one as a “show piece” while the first gets picked away at for spare parts. Even though it was ultimately a failed project, I’m glad I attempted it. For my next headphone amp, I’ll be using a professionally-engineered and designed circuit based around a PCB which should help ensure success.

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