<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom" ><generator uri="https://jekyllrb.com/" version="4.3.2">Jekyll</generator><link href="https://bdm.cc/feed.xml" rel="self" type="application/atom+xml" /><link href="https://bdm.cc/" rel="alternate" type="text/html" /><updated>2024-05-25T11:29:18-04:00</updated><id>https://bdm.cc/feed.xml</id><title type="html">bdm</title><subtitle>Brian Mayton&apos;s blog about hardware hacking and things</subtitle><author><name>Brian Mayton</name></author><entry><title type="html">Project Preview: LED Matrix Display</title><link href="https://bdm.cc/2023/05/25/led-sign-preview.html" rel="alternate" type="text/html" title="Project Preview: LED Matrix Display" /><published>2023-05-25T00:00:00-04:00</published><updated>2023-05-25T00:00:00-04:00</updated><id>https://bdm.cc/2023/05/25/led-sign-preview</id><author><name>Brian Mayton</name></author><category term="hardware" /><category term="RP2040" /><category term="fabrication" /><summary type="html"><![CDATA[This is still a work in progress: a full series of articles should be on the way, but I wanted to give a quick preview of a project I’ve been doing to explore the PIOs and network functionality of the RP2040/Raspberry Pi Pico W. This series will feature a little bit of everything: The RP2040’s PIOs Wi-fi and networking with LwIP 2-layer PCB milling and fabrication, with vias Woodworking 12-bit color graphics LED matrix modules and high speed shift registers 40-year-old classic Macintosh typography So, hopefully more content coming soon. In the meantime, here are a few more photos:]]></summary></entry><entry><title type="html">Fixing up my place on the web</title><link href="https://bdm.cc/2023/05/08/fixing-up-my-place-on-the-web.html" rel="alternate" type="text/html" title="Fixing up my place on the web" /><published>2023-05-08T00:00:00-04:00</published><updated>2023-05-08T00:00:00-04:00</updated><id>https://bdm.cc/2023/05/08/fixing-up-my-place-on-the-web</id><author><name>Brian Mayton</name></author><category term="meta" /><summary type="html"><![CDATA[This site originated back in 2009 when I started applying to graduate programs and I needed a place for an online portfolio with a handful of projects. It started out as a small collection of HTML pages, each one describing a project, that you could click through in sequence. At some point, I migrated all of the content into WordPress. I’d used WordPress before back on orderedpixels.com, which was my original blog where I posted weekly photos and updates about university life for friends and family. WordPress had improved quite a bit in the interim, and the WYSIWYG editor and upload manager made it really easy to make posts with images and everything. But in the decade that’s followed, my fondness for WordPress has waned. I won’t bother with the details here, but the experience of posting has gotten frustrating to the point where I’ve basically stopped writing anything new here. Recently, my colleagues have been encouring me to share more of my projects online. In particular, I’ve been starting to explore the RP2040 microcontroller and the Raspberry Pi Pico platforms based on it, and it seems that sharing my experiences might be helpful or at least interesting to the broader community. So that’s led me to sit down and try to sort out my blogging situation. I’m dispensing with WordPress and have switched to a static site generated with Jekyll. This lets me write posts as simple Markdown files and handles keeping all of the tricky bits like navigation and tags coherent across the whole site. But the end result is plain old HTML—nothing to render on the server and no client-side JavaScript. I’ve tried to migrate over all of the old content, and hopefully any existing permalinks should continue to work. I’ve even fixed up the images on some of the original pages that have been broken since the site migrated to WordPress over a decade ago. The exception is that user-posted comments are gone (in practice, there were only ever a few of these; mostly the feature was just a magnet for spambots). If you want to get in touch or comment on a post, you can always send e-mail to me at my initials (the three letters in the logo) at the domain of this site. Anyway, hopefully this works out and there will be some new content coming soon. There’s an Atom feed you can add to your reader if you want to subscribe to new posts.]]></summary></entry><entry><title type="html">Milling Circuit Boards</title><link href="https://bdm.cc/2020/10/14/milling-circuit-boards.html" rel="alternate" type="text/html" title="Milling Circuit Boards" /><published>2020-10-14T00:00:00-04:00</published><updated>2020-10-14T00:00:00-04:00</updated><id>https://bdm.cc/2020/10/14/milling-circuit-boards</id><author><name>Brian Mayton</name></author><category term="fabrication" /><category term="hardware" /><summary type="html"><![CDATA[For the past 12 or so years, the AT86RF23x 802.15.4 radios have been my go-to for low-power digital communication. They work pretty well, and I have a good software stack and protocols built up around them (which my friends decided should be called “Bri-Fi.”) They’re sort of expensive, though—the bare chips are a few dollars each and modules were at least $20-30 last I looked. On a fully custom sensor board they’re not that bad, but for random side projects where I just want two things to talk to each other wirelessly, the cost of the chips and doing an RF layout are kind of annoying. I’ve been seeing a lot of Nordic’s nRF24L01+ radios in the maker community. It seems there’s a pretty good Arduino library and the modules are available super cheap. I think I got five complete modules for about what I’d pay for one of the RF233 chips. Anyway, I’m playing around with these modules and put together a couple of quick PCBs to try them out. I’ve been getting pretty good results milling boards at home using my little CNC router, so I thought I’d snap a few photos and write a “quick” blog post. This board is a little USB-to-RF bridge based around the ATmega32U2. If this works, it’s going to be the computer side of a custom user input device. Not an ideal layout for an RF board, but some compromises are generally required to make things work in a single layer.]]></summary></entry><entry><title type="html">Lightning Damage</title><link href="https://bdm.cc/2018/08/13/lightning-damage.html" rel="alternate" type="text/html" title="Lightning Damage" /><published>2018-08-13T00:00:00-04:00</published><updated>2018-08-13T00:00:00-04:00</updated><id>https://bdm.cc/2018/08/13/lightning-damage</id><author><name>Brian Mayton</name></author><category term="hardware" /><category term="diagnosis" /><category term="tidmarsh" /><summary type="html"><![CDATA[Last week, lightning struck at Tidmarsh, the former cranberry bog where I’m conducting experiments for my Ph.D. research on sensor networks. We’ve had some nearby lightning strikes before that have caused some minor equipment damage (it’s one of the perils of working in this environment) but nothing quite so major as this. We have some protection against lightning—perhaps not as much as we should have, but it can be quite challenging when we have many cables extending out over a large area. I was actually there on site when it happened, making myself a cup of tea in the guesthouse. I was looking the wrong way to see the actual bolt, but saw a flash and heard the thunder instantaneously, so that must have been it. We lost pretty much the entire audio installation at the former impoundment. Closer examination of the damaged equipment tells the story of the path the current took. I don’t think anything was hit directly, or the damage would have been even more extensive. Most likely, the lightning hit the ground very close to where one of our cameras is out in the marsh. That traveled about 150 meters through a CAT6 ethernet line, into port 4 on the switch in the south box:]]></summary></entry><entry><title type="html">Lenovo Bluetooth keyboard repairs</title><link href="https://bdm.cc/2016/06/05/lenovo-bluetooth-keyboard-repairs.html" rel="alternate" type="text/html" title="Lenovo Bluetooth keyboard repairs" /><published>2016-06-05T00:00:00-04:00</published><updated>2016-06-05T00:00:00-04:00</updated><id>https://bdm.cc/2016/06/05/lenovo-bluetooth-keyboard-repairs</id><author><name>Brian Mayton</name></author><category term="repair" /><category term="diagnosis" /><summary type="html"><![CDATA[For one of my home desktop setups, I have very particular keyboard requirements. Since I put the keyboard in my lap (there’s no desk/table, the monitor is suspended on a cantilevered arm) the pointing device needs to be integrated into the keyboard itself. I’ve become less of a fan of trackpads over the years, especially the terrible ones that are integrated into cheap wireless keyboard combos like the ubiquitous Logitech K400. Furthermore, as it’s a Linux machine and I’m very accustomed to the X11 clipboard, which uses the middle mouse button to paste, I want a physical middle button. I’ve only found one wireless keyboard that meets those requirements, and it’s Lenovo’s bluetooth keyboard with a TrackPoint: I like the keyboards and TrackPoints on my ThinkPads, so it’s nice to have the same setup. Unfortunately, the wireless keyboard is a bit of a regression from the ones on my ThinkPads: it lacks the row above the function keys, the function keys have tiny markings with big icons for their secondary functions (which I don’t care about) and the build quality is overall not as good as older ThinkPads. I also don’t like Bluetooth (pairing is complicated, and it doesn’t work in the bootloader/BIOS). But, it works. Well, it did, at least until my TrackPoint stopped working one day. The keyboard continued to work, but the TrackPoint started drifting incessantly to the upper left no matter how it was deflected, followed by ceasing to work altogether (including the buttons) a couple of days later.]]></summary></entry><entry><title type="html">ADAT modification for the Layla converters</title><link href="https://bdm.cc/2014/02/08/adat-layla.html" rel="alternate" type="text/html" title="ADAT modification for the Layla converters" /><published>2014-02-08T00:00:00-05:00</published><updated>2014-02-08T00:00:00-05:00</updated><id>https://bdm.cc/2014/02/08/adat-layla</id><author><name>Brian Mayton</name></author><category term="audio" /><category term="hardware" /><category term="reverse_engineering" /><summary type="html"><![CDATA[Background and Motivation Since this project involves a bunch of digital audio stuff that some of my readers might not be familiar with, I’ll start by describing my motivation for the project and some of the background information about the protocols and hardware involved. If you’re already familiar with this stuff and just want to see the hack, jump to the next section. I have a somewhat unusual audio setup at home. I use a DAW (digital audio workstation) software on my desktop computer as a digital mixer for all of the sound coming from it. Using JACK on Linux, I route the output of each program to a different mixer channel, so in addition to having different volume settings for each program, I can apply effects as well (such as equalization or applying a little bit of compression when watching a movie late at night, so the loud parts aren’t quite so loud.) I can then route the audio between multiple outputs, primarily my studio monitors and my headphone amplifier. The sound card I use is an RME Digi9652. These are older PCI cards, which are now inexpensively available second-hand since newer computers have mostly PCI-e slots instead. But, the card still works on my motherboard, has great Linux support, and provides 26 inputs and 26 outputs with very low latency. Like many multichannel audio cards, all of the I/O is digital. The 9652 has three pairs of ADAT Lightpipe ports and one pair of coaxial S/PDIF connectors. In order to get analog audio in and out, it requires the use of external converters connected to the ADAT ports.]]></summary></entry><entry><title type="html">Lighting Control Boards</title><link href="https://bdm.cc/2013/11/11/mr16board.html" rel="alternate" type="text/html" title="Lighting Control Boards" /><published>2013-11-11T00:00:00-05:00</published><updated>2013-11-11T00:00:00-05:00</updated><id>https://bdm.cc/2013/11/11/mr16board</id><author><name>Brian Mayton</name></author><category term="hardware" /><category term="medialab" /><summary type="html"><![CDATA[I designed these boards to be integrated into 12VDC track lighting fixtures with MR16 LED lamps in the Media Lab atrium. They are based on the Atmel XMega A4 series (originally designed for the ATxmega32A4 and that’s what’s in the atrium lighting installation, but forwards-compatible with the A4U series chips; most of my current uses for this board use the ATxmega128A4U) and the AT86RF231 radio (though the RF230 and newer variants like the RF233 should also be usable.)]]></summary></entry><entry><title type="html">Printing Functional Objects with the Form 1</title><link href="https://bdm.cc/2013/08/30/printing-functional-objects-with-the-form-1.html" rel="alternate" type="text/html" title="Printing Functional Objects with the Form 1" /><published>2013-08-30T00:00:00-04:00</published><updated>2013-08-30T00:00:00-04:00</updated><id>https://bdm.cc/2013/08/30/printing-functional-objects-with-the-form-1</id><author><name>Brian Mayton</name></author><category term="hardware" /><category term="fabrication" /><summary type="html"><![CDATA[3D-printed microphone clip and custom-built microphone. Please excuse the messy desk in the background. The idea of starting with a digital model of a 3D object and having a physical representation in your hands a few hours later is certainly kind of magical. I remember when my department at UW got its first 3D printer (which cost about as much as a nice car and was the size of a refrigerator) I spent hours staring through its window, watching it build up objects a layer at a time. Amazingly, just a few years later, there are now several desktop-sized printers available at a fraction of the cost. With the recent availability of these “personal” 3D printers, it’s been interesting to see the resulting models that people have printed. I’ve yet to see one that doesn’t have a few chess pieces and an Eiffel Tower or two sitting next to it, showing off its capabilities. While these intricate models are definitely cool, 3D printing isn’t just about models that look nice. To me, the real value of 3D printing is being able to print out physical models that are functional, that wouldn’t otherwise be easy to obtain. I’ve recently been working with the Form 1, which is a recent desktop-sized 3D printer capable of some pretty impressive prints. While I’ve certainly printed a few things that are just for looking at, I’ve also been using it to make functional objects. And so far, I’ve been pretty happy.]]></summary></entry><entry><title type="html">The ZigBoard (working title)</title><link href="https://bdm.cc/2010/09/26/the-zigboard-working-title.html" rel="alternate" type="text/html" title="The ZigBoard (working title)" /><published>2010-09-26T00:00:00-04:00</published><updated>2010-09-26T00:00:00-04:00</updated><id>https://bdm.cc/2010/09/26/the-zigboard-working-title</id><author><name>Brian Mayton</name></author><category term="hardware" /><category term="rf" /><summary type="html"><![CDATA[Computer rendering of prototype board. Created with Altium Designer 6.9; components modeled in SolidWorks 2009 Many small projects seem like they would benefit from low-power, low-bandwidth wireless connectivity. Commercial modules such as the excellent XBee series of devices exist, but are relatively large, expensive, and seem better suited to tinkering with the technology than integration into a finished project. Single-chip RF transceiver solutions are small and inexpensive, but require a fabricated PCB for every design. My goal with this project is to develop an inexpensive and small RF transceiver module that is flexible enough to use in the prototyping stages of a project while not being so general and large that it’s wasteful to use in a finished work.]]></summary></entry><entry><title type="html">An Electric Field Pretouch System for Grasping and Co-Manipulation</title><link href="https://bdm.cc/2010/01/03/an-electric-field-pretouch-system-for-grasping-and-co-manipulation.html" rel="alternate" type="text/html" title="An Electric Field Pretouch System for Grasping and Co-Manipulation" /><published>2010-01-03T00:00:00-05:00</published><updated>2010-01-03T00:00:00-05:00</updated><id>https://bdm.cc/2010/01/03/an-electric-field-pretouch-system-for-grasping-and-co-manipulation</id><author><name>Brian Mayton</name></author><category term="robotics" /><category term="research" /><category term="sensing" /><summary type="html"><![CDATA[Pretouch is a sense that is longer range than touch, but shorter than vision. Using electric field sensing hardware that I designed to fit inside a robot’s fingers, several robotic manipulation tasks are made easier or possible.]]></summary></entry></feed>