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| -rw-r--r-- | _projects/e-reader.md | 58 | ||||
| -rw-r--r-- | _projects/fpm-door-lock.md | 10 | ||||
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| -rw-r--r-- | _site/blog/index.html | 2 | ||||
| -rw-r--r-- | _site/blog/suckless-software/index.html | 35 | ||||
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| -rw-r--r-- | _site/projects/bumblebee/index.html | 17 | ||||
| -rw-r--r-- | _site/projects/e-reader/index.html | 58 | ||||
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diff --git a/_blog/suckless-software.md b/_blog/suckless-software.md index 86fb5bc..97d437e 100644 --- a/_blog/suckless-software.md +++ b/_blog/suckless-software.md @@ -1,5 +1,5 @@ --- -title: How I manage Suckless software packages +title: How I manage Suckless software installations date: 2025-11-30 layout: post --- @@ -13,8 +13,7 @@ versions are released. ## Initial setup When using a suckless program, I usually begin by cloning the project and -setting the remote URL to push a copy of the source code with my patches to my -own git repository: +setting the remote push URL to my own git repository: ``` git clone git://git.suckless.org/dwm @@ -23,28 +22,28 @@ git remote set-url --push origin git@git.asciimx.com:/repos/dwm ``` This way, I can pull updates from the upstream project whenever I want, while -committing my changes to my own git repository. The git reset command aligns my +committing my changes to my git repository. The git reset command aligns my branch head with a stable release before applying patches or installing the software. If all I want to do is reconfigure the software (e.g., change key bindings), which is what I need most of the time, the recommended approach is to modify -the config.h file. If the config.h isn't yet in the project, the following -command generates it from the defaults and compiles the software using `make -clean <target>` here `<target>` is the name of the application (e.g., dwm) -found in the Makefile. I modify the resulting config.h file and run `make clean -install` to install the software before committing and pushing my changes to my -git repo. +the config.h file. If the config.h isn't yet in the project, the +`make clean <target>` command will generate it from the defaults and compile +the software. The `<target>` is the name of the application (e.g., dwm) found +in the Makefile. I modify the resulting config.h file and run `make clean +install` to install the software before committing and pushing my changes to +the git repo. ## dwm and slstatus Since dwm and slstatus are always running, `make install` will likely fail for -them. The operating system will prevent the installer from replacing running +them. The operating system may prevent the installer from replacing running executables with new ones. Hence, we must first stop the running instances of -these programs (Mod + Shift + q). Then, switch to a tty (Ctrl + Alt + F1), -log in, and change the directory to where dwm/slstatus is. We can run `make -install` to install the software and switch back to the graphical session -(Ctrl + Alt + F5). +these programs (in my case, using Mod + Shift + q). Then, switch to a tty +(Ctrl + Alt + F1), log in, and change the directory to where dwm/slstatus is. +We can run `make install` to install the software and switch back to the +graphical session (Ctrl + Alt + F5). The key combinations for switching to the tty and back may differ across systems. The ones listed above are for OpenBSD. @@ -86,5 +85,5 @@ q12vu Another old commit. 3fkdf Version 6.5. ``` -And finally, commit and push all the changes to my own git repository. +And finally, I commit and push all the changes to my git repository. diff --git a/_projects/bumblebee.md b/_projects/bumblebee.md index a114140..b322969 100644 --- a/_projects/bumblebee.md +++ b/_projects/bumblebee.md @@ -37,15 +37,16 @@ src="https://github.com/desjarlais/Scintilla.NET" class="external" target="_blank" rel="noopener noreferrer">Scintilla.NET</a> editor), debounce events, and block hidden elements and scripts. -Before settling on a desktop application, we contemplated a browser extension. -We decided against that because we didn't want the browser vendor to dictate -Bumblebee's capabilities. Furthermore, the company's security policy prohibited -browser extensions, complicating its deployment. The initial prototype used a -C# wrapper of the Chromium project instead of WebView. WebView's more intuitive +Before settling on a desktop application, we contemplated designing Bumblebee +as a browser extension. We decided against that because we didn't want the +browser vendors to dictate Bumblebee's capabilities. Besides, the company's +security policy, which prohibited browser extensions, would have complicated +the deployment of an extension-based solution. The initial prototype used a C# +wrapper of the Chromium project instead of WebView. WebView's more intuitive API and its seamless integration with Windows Forms led us to choose it over the Chromium wrapper. -Bumblebee reduced the time we spent on authoring scripts from hours to a few -minutes. Since the rules for code generation were written and optimized by -experts in web technologies, the output was more robust. +Bumblebee predictably reduced the time we spent on authoring scripts from hours +to a few minutes. Since the code generation rules were written and optimized by +experts in web technologies, the quality of the scripts improved as well. diff --git a/_projects/e-reader.md b/_projects/e-reader.md index 1a0892e..3405cc8 100644 --- a/_projects/e-reader.md +++ b/_projects/e-reader.md @@ -1,14 +1,14 @@ --- -title: Prototype e-reader +title: Experimental e-reader date: 2023-10-24 thumbnail: thumb.png layout: post --- -This project features a prototype e-reader powered by an ESP-WROOM-32 -development board and a 7.5-inch <a href="https://www.waveshare.com/" -class="external" target="_blank" rel="noopener noreferrer">Waveshare</a> -e-paper display. +This project features a minimal e-reader powered by an ESP-WROOM-32 development +board and a 7.5-inch <a href="https://www.waveshare.com/" class="external" +target="_blank" rel="noopener noreferrer">Waveshare</a> e-paper display built +with the intention of learning about e-paper displays. <video style="max-width:100%;" controls="" poster="thumb.png"> <source src="ereader.mp4" type="video/mp4"> @@ -29,13 +29,13 @@ minimize power consumption when not in use and records the reading progress in the chip's RTC memory. The most formidable challenge when trying to build an e-reader with an ESP32 -board is its limited memory and storage. My ESP-WROOM-32 board has 512 KB of -SRAM and 4 MB of flash memory, which the freeRTOS, ESP-IDF, and the e-reader +board is its limited memory and storage. My ESP-WROOM-32 board has 512KB of +SRAM and 4MB of flash memory, which the freeRTOS, ESP-IDF, and the e-reader application must share. To put things into perspective, a Kindle Paperwhite has -at least 256 MB of memory and 8 GB of storage. +at least 256MB of memory and 8GB of storage. Despite its size, as microcontrollers go, ESP32 is a powerful system-on-a-chip -with a 160 MHz dual-core processor and integrated WiFi. So, I thought it’d be +with a 160MHz dual-core processor and integrated WiFi. So, I thought it’d be amusing to embrace the constraints and build my e-reader using a $5 MCU and the power of C programming. @@ -48,7 +48,7 @@ monochrome image of a page (a .ebm file). The EBM file contains a series of bitmaps, one for each page of the book. The dimensions of each bitmap are equal to the size of the display. Each byte of the bitmap encodes information for rendering eight pixels. For my display, -which has a resolution of 480x800, the bitmaps are laid out along 48 KB +which has a resolution of 480x800, the bitmaps are laid out along 48KB boundaries. This simple file format lends well to HTTP streaming, which is its main advantage, as we will soon see. @@ -57,20 +57,20 @@ PDF documents to EBM files. ## How does it work? -As the e-reader has no storage, it can't store books locally. Instead, I first -have to upload the EBM file I want to read to a web server. The `EBM_ARCH_URL` -setting in the Kconfig.projbuild file points to the URL of the file. To read a -different book, I create an EBM file with the same name and upload it to the -original location. That way, I don't have to modify the `EBM_ARCH_URL` value, -which requires recompiling the embedded software. +As the e-reader has no storage, it can't store books locally. Instead, it +downloads pages of the EBM file over HTTP from the location pointed to by the +`EBM_ARCH_URL` setting in the Kconfig.projbuild file on demand. To read a +different book, we have to replace the old file with the new one or change the +`EBM_ARCH_URL` value. The latter requires us to recompile the embedded +software. Upon powering up, the e-reader checks the reading progress stored in the RTC memory. It then downloads three pages (current, previous, and next) to a -circular buffer in DMA-capable memory. When the user turns a page, one of the -microprocessor's two cores transfers it from the buffer to the display over a -Serial Peripheral Interface (SPI). The other downloads a new page in the -background. I use the ESP-IDF task API to distribute the two tasks between the -available cores for maximum parallelism. +circular buffer in DMA-capable memory. When the user turns a page by pressing a +button, one of the microprocessor's two cores transfers it from the buffer to +the display over a Serial Peripheral Interface (SPI). The other downloads a new +page in the background. I used the ESP-IDF's task API to distribute the two +tasks between the available cores to make the reader more responsive. I designed the EBM format with HTTP streaming in mind. Since the pages are laid out in the EBM file along predictable boundaries, the e-reader can request @@ -80,11 +80,15 @@ web server will process this request without custom logic. ## Reflections It's been six years since the car park and the displays. I began this project -hoping to learn the low-level workings of e-paper displays. As a bonus, it led -me to explore some of ESP32's most fascinating features: sleep modes, multicore -processing, DMA, and RTC memory. Embedded systems are magical things: invisible -particles swirl into form as the programmer whispers C. - - +hoping to learn more about e-paper displays, and I got that and more. By +working within the constraints of the ESP32, I forced myself to explore some of +its advanced features: sleep modes, multicore task scheduling, DMA transfers, +and RTC memory. + +As for the prototype, while it's no match for a commercial e-reader with +features like an offline library of books and touch screens, there's something +to be said about reading on hardware you built yourself. You are no longer the +powerless Muggle watching others perform magic. You are the wizard who makes +the invisible particles swirl into form by whispering C to it. Files: [source.tar.gz](source.tar.gz) diff --git a/_projects/fpm-door-lock.md b/_projects/fpm-door-lock.md index a94b9e0..b2a0165 100644 --- a/_projects/fpm-door-lock.md +++ b/_projects/fpm-door-lock.md @@ -14,11 +14,11 @@ microcontroller. ## Overview -The lock comprises three subsystems: the ATmega328P, an R503 fingerprint -sensor, and an FS5106B high-torque servo. The sensor mounted on the front -surface of the door enables users to unlock it from the outside. The servo is -attached to the interior door knob. The MCU must be installed at the back of -the door to prevent unauthorized users from tampering with it. +The lock comprises three subsystems: the ATmega328P microcontroller, an R503 +fingerprint sensor, and an FS5106B high-torque servo. The sensor mounted on the +front surface of the door enables users to unlock it from the outside. The +servo is attached to the interior door knob. The MCU must be installed at the +back of the door to prevent unauthorized users from tampering with it. When no one is interacting with the lock, the MCU is in deep sleep. The sensor and the servo each draw 13.8mA and 4.6mA of quiescent currents. To prevent this diff --git a/_site/about/index.html b/_site/about/index.html index 060f09d..6c44c47 100644 --- a/_site/about/index.html +++ b/_site/about/index.html @@ -49,7 +49,7 @@ <h4>Navigation</h4> <ul> - <li>hme: Home page, listing latest articles.</li> + <li>hme: Home page, listing the latest articles.</li> <li>blg: Notes and tutorials about software and embedded systems.</li> <li>poc: Projects, prototypes, and experiments.</li> <li>abt: Site information.</li> diff --git a/_site/blog/index.html b/_site/blog/index.html index c213ee5..84a22b6 100644 --- a/_site/blog/index.html +++ b/_site/blog/index.html @@ -46,7 +46,7 @@ <tr> <td class="posts-td posts-td-link"> - <a href="/blog/suckless-software/" class="link-decor-none">How I manage Suckless software packages</a> + <a href="/blog/suckless-software/" class="link-decor-none">How I manage Suckless software installations</a> </td> <td class="posts-td posts-td-time"> <span class="post-meta"> diff --git a/_site/blog/suckless-software/index.html b/_site/blog/suckless-software/index.html index ea91072..bab40c6 100644 --- a/_site/blog/suckless-software/index.html +++ b/_site/blog/suckless-software/index.html @@ -2,12 +2,12 @@ <html> <head> <meta charset="utf-8"> - <title>How I manage Suckless software packages</title> + <title>How I manage Suckless software installations</title> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> - <title>How I manage Suckless software packages</title> + <title>How I manage Suckless software installations</title> <link rel="stylesheet" href="/assets/css/main.css"> <link rel="stylesheet" href="/assets/css/skeleton.css"> </head> @@ -41,7 +41,7 @@ <main> <div class="container"> <div class="container-2"> - <h2 class="center" id="title">HOW I MANAGE SUCKLESS SOFTWARE PACKAGES</h2> + <h2 class="center" id="title">HOW I MANAGE SUCKLESS SOFTWARE INSTALLATIONS</h2> <h6 class="center">30 NOVEMBER 2025</h5> <br> <div class="twocol justify"><p>Since <a href="https://suckless.org/" class="external" target="_blank" rel="noopener noreferrer">suckless</a> software requires users to modify the @@ -52,8 +52,7 @@ versions are released.</p> <h2 id="initial-setup">Initial setup</h2> <p>When using a suckless program, I usually begin by cloning the project and -setting the remote URL to push a copy of the source code with my patches to my -own git repository:</p> +setting the remote push URL to my own git repository:</p> <div class="language-plaintext highlighter-rouge"><div class="highlight"><pre class="highlight"><code>git clone git://git.suckless.org/dwm git reset --hard <tag> @@ -61,28 +60,28 @@ git remote set-url --push origin git@git.asciimx.com:/repos/dwm </code></pre></div></div> <p>This way, I can pull updates from the upstream project whenever I want, while -committing my changes to my own git repository. The git reset command aligns my +committing my changes to my git repository. The git reset command aligns my branch head with a stable release before applying patches or installing the software.</p> <p>If all I want to do is reconfigure the software (e.g., change key bindings), which is what I need most of the time, the recommended approach is to modify -the config.h file. If the config.h isn’t yet in the project, the following -command generates it from the defaults and compiles the software using <code class="language-plaintext highlighter-rouge">make -clean <target></code> here <code class="language-plaintext highlighter-rouge"><target></code> is the name of the application (e.g., dwm) -found in the Makefile. I modify the resulting config.h file and run <code class="language-plaintext highlighter-rouge">make clean -install</code> to install the software before committing and pushing my changes to my -git repo.</p> +the config.h file. If the config.h isn’t yet in the project, the +<code class="language-plaintext highlighter-rouge">make clean <target></code> command will generate it from the defaults and compile +the software. The <code class="language-plaintext highlighter-rouge"><target></code> is the name of the application (e.g., dwm) found +in the Makefile. I modify the resulting config.h file and run <code class="language-plaintext highlighter-rouge">make clean +install</code> to install the software before committing and pushing my changes to +the git repo.</p> <h2 id="dwm-and-slstatus">dwm and slstatus</h2> <p>Since dwm and slstatus are always running, <code class="language-plaintext highlighter-rouge">make install</code> will likely fail for -them. The operating system will prevent the installer from replacing running +them. The operating system may prevent the installer from replacing running executables with new ones. Hence, we must first stop the running instances of -these programs (Mod + Shift + q). Then, switch to a tty (Ctrl + Alt + F1), -log in, and change the directory to where dwm/slstatus is. We can run <code class="language-plaintext highlighter-rouge">make -install</code> to install the software and switch back to the graphical session -(Ctrl + Alt + F5).</p> +these programs (in my case, using Mod + Shift + q). Then, switch to a tty +(Ctrl + Alt + F1), log in, and change the directory to where dwm/slstatus is. +We can run <code class="language-plaintext highlighter-rouge">make install</code> to install the software and switch back to the +graphical session (Ctrl + Alt + F5).</p> <p>The key combinations for switching to the tty and back may differ across systems. The ones listed above are for OpenBSD.</p> @@ -121,7 +120,7 @@ q12vu Another old commit. 3fkdf Version 6.5. </code></pre></div></div> -<p>And finally, commit and push all the changes to my own git repository.</p> +<p>And finally, I commit and push all the changes to my git repository.</p> </div> <p class="post-author right">by W. D. Sadeep Madurange</p> diff --git a/_site/feed.xml b/_site/feed.xml index a5979a1..8a973b4 100644 --- a/_site/feed.xml +++ b/_site/feed.xml @@ -1 +1 @@ -<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom" ><generator uri="https://jekyllrb.com/" version="4.4.1">Jekyll</generator><link href="/feed.xml" rel="self" type="application/atom+xml" /><link href="/" rel="alternate" type="text/html" /><updated>2025-12-09T23:04:17+08:00</updated><id>/feed.xml</id><title type="html">ASCIIMX | Blog</title><author><name>W. D. Sadeep Madurange</name></author><entry><title type="html">How I manage Suckless software packages</title><link href="/blog/suckless-software/" rel="alternate" type="text/html" title="How I manage Suckless software packages" /><published>2025-11-30T00:00:00+08:00</published><updated>2025-11-30T00:00:00+08:00</updated><id>/blog/suckless-software</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[Since suckless software requires users to modify the source code and recompile to customize, I need a way to maintain patches over the long term while retaining the ability to upgrade the software as new versions are released.]]></summary></entry><entry><title type="html">Neo4J A* search</title><link href="/blog/neo4j-a-star-search/" rel="alternate" type="text/html" title="Neo4J A* search" /><published>2025-09-14T00:00:00+08:00</published><updated>2025-09-14T00:00:00+08:00</updated><id>/blog/neo4j-a-star-search</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[Back in 2018, we used Neo4J graph database to track the movement of marine vessels. We were interested in the shortest path a ship could take through a network of about 13,000 route points. Algorithms based on graph theory, such as A* search, provide optimal solutions to such problems. In other words, the set of route points lends itself well to a model based on graphs.]]></summary></entry><entry><title type="html">MOSFETs as electronic switches</title><link href="/blog/mosfet-switches/" rel="alternate" type="text/html" title="MOSFETs as electronic switches" /><published>2025-06-22T00:00:00+08:00</published><updated>2025-06-22T00:00:00+08:00</updated><id>/blog/mosfet-switches</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[Recently, I needed a low-power circuit for one of my battery-operated projects. Much of the system’s power savings depended on its ability to electronically switch off components, such as servos, that draw high levels of quiescent currents. My search for a solution led me to MOSFETs, transistors capable of controlling circuits operating at voltages far above their own.]]></summary></entry><entry><title type="html">How to configure ATmega328P microcontrollers to run at 3.3V and 5V</title><link href="/blog/arduino-uno/" rel="alternate" type="text/html" title="How to configure ATmega328P microcontrollers to run at 3.3V and 5V" /><published>2025-04-10T00:00:00+08:00</published><updated>2025-04-10T00:00:00+08:00</updated><id>/blog/arduino-uno</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[This is a quick reference for wiring up ATmega328P ICs to run at 5V and 3.3V. While the 5V configuration is common, the 3.3V configuration can be useful in low-power applications and when interfacing with parts that themselves run at 3.3V. In this guide, the 5V setup is configured with a 16MHz crystal oscillator, while the 3.3V configuration makes use of an 8MHz crystal oscillator.]]></summary></entry><entry><title type="html">How to set up ATSAM3X8E microcontrollers for bare-metal programming in C</title><link href="/blog/arduino-due/" rel="alternate" type="text/html" title="How to set up ATSAM3X8E microcontrollers for bare-metal programming in C" /><published>2024-10-05T00:00:00+08:00</published><updated>2024-10-05T00:00:00+08:00</updated><id>/blog/arduino-due</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[This article is a step-by-step guide for programming bare-metal ATSAM3X8E chips found on Arduino Due boards. It also includes notes on the chip’s memory layout relevant for writing linker scripts. The steps described in this article were tested on an OpenBSD workstation.]]></summary></entry></feed>
\ No newline at end of file +<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom" ><generator uri="https://jekyllrb.com/" version="4.4.1">Jekyll</generator><link href="/feed.xml" rel="self" type="application/atom+xml" /><link href="/" rel="alternate" type="text/html" /><updated>2025-12-11T22:00:02+08:00</updated><id>/feed.xml</id><title type="html">ASCIIMX | Blog</title><author><name>W. D. Sadeep Madurange</name></author><entry><title type="html">How I manage Suckless software installations</title><link href="/blog/suckless-software/" rel="alternate" type="text/html" title="How I manage Suckless software installations" /><published>2025-11-30T00:00:00+08:00</published><updated>2025-11-30T00:00:00+08:00</updated><id>/blog/suckless-software</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[Since suckless software requires users to modify the source code and recompile to customize, I need a way to maintain patches over the long term while retaining the ability to upgrade the software as new versions are released.]]></summary></entry><entry><title type="html">Neo4J A* search</title><link href="/blog/neo4j-a-star-search/" rel="alternate" type="text/html" title="Neo4J A* search" /><published>2025-09-14T00:00:00+08:00</published><updated>2025-09-14T00:00:00+08:00</updated><id>/blog/neo4j-a-star-search</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[Back in 2018, we used Neo4J graph database to track the movement of marine vessels. We were interested in the shortest path a ship could take through a network of about 13,000 route points. Algorithms based on graph theory, such as A* search, provide optimal solutions to such problems. In other words, the set of route points lends itself well to a model based on graphs.]]></summary></entry><entry><title type="html">MOSFETs as electronic switches</title><link href="/blog/mosfet-switches/" rel="alternate" type="text/html" title="MOSFETs as electronic switches" /><published>2025-06-22T00:00:00+08:00</published><updated>2025-06-22T00:00:00+08:00</updated><id>/blog/mosfet-switches</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[Recently, I needed a low-power circuit for one of my battery-operated projects. Much of the system’s power savings depended on its ability to electronically switch off components, such as servos, that draw high levels of quiescent currents. My search for a solution led me to MOSFETs, transistors capable of controlling circuits operating at voltages far above their own.]]></summary></entry><entry><title type="html">How to configure ATmega328P microcontrollers to run at 3.3V and 5V</title><link href="/blog/arduino-uno/" rel="alternate" type="text/html" title="How to configure ATmega328P microcontrollers to run at 3.3V and 5V" /><published>2025-04-10T00:00:00+08:00</published><updated>2025-04-10T00:00:00+08:00</updated><id>/blog/arduino-uno</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[This is a quick reference for wiring up ATmega328P ICs to run at 5V and 3.3V. While the 5V configuration is common, the 3.3V configuration can be useful in low-power applications and when interfacing with parts that themselves run at 3.3V. In this guide, the 5V setup is configured with a 16MHz crystal oscillator, while the 3.3V configuration makes use of an 8MHz crystal oscillator.]]></summary></entry><entry><title type="html">How to set up ATSAM3X8E microcontrollers for bare-metal programming in C</title><link href="/blog/arduino-due/" rel="alternate" type="text/html" title="How to set up ATSAM3X8E microcontrollers for bare-metal programming in C" /><published>2024-10-05T00:00:00+08:00</published><updated>2024-10-05T00:00:00+08:00</updated><id>/blog/arduino-due</id><author><name>W. D. Sadeep Madurange</name></author><summary type="html"><![CDATA[This article is a step-by-step guide for programming bare-metal ATSAM3X8E chips found on Arduino Due boards. It also includes notes on the chip’s memory layout relevant for writing linker scripts. The steps described in this article were tested on an OpenBSD workstation.]]></summary></entry></feed>
\ No newline at end of file diff --git a/_site/index.html b/_site/index.html index 6d65535..ce4616f 100644 --- a/_site/index.html +++ b/_site/index.html @@ -56,7 +56,7 @@ <tr> <td class="posts-td posts-td-link"> - <a href="/blog/suckless-software/" class="link-decor-none">How I manage Suckless software packages</a> + <a href="/blog/suckless-software/" class="link-decor-none">How I manage Suckless software installations</a> </td> <td class="posts-td posts-td-time"> <span class="post-meta"> diff --git a/_site/posts.xml b/_site/posts.xml index 537fbb6..e303b1c 100644 --- a/_site/posts.xml +++ b/_site/posts.xml @@ -1 +1 @@ -<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom" ><generator uri="https://jekyllrb.com/" version="4.4.1">Jekyll</generator><link href="/posts.xml" rel="self" type="application/atom+xml" /><link href="/" rel="alternate" type="text/html" /><updated>2025-12-09T23:04:17+08:00</updated><id>/posts.xml</id><title type="html">ASCIIMX</title><author><name>W. D. Sadeep Madurange</name></author></feed>
\ No newline at end of file +<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom" ><generator uri="https://jekyllrb.com/" version="4.4.1">Jekyll</generator><link href="/posts.xml" rel="self" type="application/atom+xml" /><link href="/" rel="alternate" type="text/html" /><updated>2025-12-11T22:00:02+08:00</updated><id>/posts.xml</id><title type="html">ASCIIMX</title><author><name>W. D. Sadeep Madurange</name></author></feed>
\ No newline at end of file diff --git a/_site/projects/bumblebee/index.html b/_site/projects/bumblebee/index.html index 7004f2e..d6873e4 100644 --- a/_site/projects/bumblebee/index.html +++ b/_site/projects/bumblebee/index.html @@ -73,17 +73,18 @@ websites and pop-ups. The user can access developer tools, override any part of the script at any point during the session (using the embedded <a src="https://github.com/desjarlais/Scintilla.NET" class="external" target="_blank" rel="noopener noreferrer">Scintilla.NET</a> editor), debounce events, and block hidden elements and scripts.</p> -<p>Before settling on a desktop application, we contemplated a browser extension. -We decided against that because we didn’t want the browser vendor to dictate -Bumblebee’s capabilities. Furthermore, the company’s security policy prohibited -browser extensions, complicating its deployment. The initial prototype used a -C# wrapper of the Chromium project instead of WebView. WebView’s more intuitive +<p>Before settling on a desktop application, we contemplated designing Bumblebee +as a browser extension. We decided against that because we didn’t want the +browser vendors to dictate Bumblebee’s capabilities. Besides, the company’s +security policy, which prohibited browser extensions, would have complicated +the deployment of an extension-based solution. The initial prototype used a C# +wrapper of the Chromium project instead of WebView. WebView’s more intuitive API and its seamless integration with Windows Forms led us to choose it over the Chromium wrapper.</p> -<p>Bumblebee reduced the time we spent on authoring scripts from hours to a few -minutes. Since the rules for code generation were written and optimized by -experts in web technologies, the output was more robust.</p> +<p>Bumblebee predictably reduced the time we spent on authoring scripts from hours +to a few minutes. Since the code generation rules were written and optimized by +experts in web technologies, the quality of the scripts improved as well.</p> </div> <p class="post-author right">by W. D. Sadeep Madurange</p> diff --git a/_site/projects/e-reader/index.html b/_site/projects/e-reader/index.html index 5fe3341..2e04274 100644 --- a/_site/projects/e-reader/index.html +++ b/_site/projects/e-reader/index.html @@ -2,12 +2,12 @@ <html> <head> <meta charset="utf-8"> - <title>Prototype e-reader</title> + <title>Experimental e-reader</title> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> - <title>Prototype e-reader</title> + <title>Experimental e-reader</title> <link rel="stylesheet" href="/assets/css/main.css"> <link rel="stylesheet" href="/assets/css/skeleton.css"> </head> @@ -41,12 +41,12 @@ <main> <div class="container"> <div class="container-2"> - <h2 class="center" id="title">PROTOTYPE E-READER</h2> + <h2 class="center" id="title">EXPERIMENTAL E-READER</h2> <h6 class="center">24 OCTOBER 2023</h5> <br> - <div class="twocol justify"><p>This project features a prototype e-reader powered by an ESP-WROOM-32 -development board and a 7.5-inch <a href="https://www.waveshare.com/" class="external" target="_blank" rel="noopener noreferrer">Waveshare</a> -e-paper display.</p> + <div class="twocol justify"><p>This project features a minimal e-reader powered by an ESP-WROOM-32 development +board and a 7.5-inch <a href="https://www.waveshare.com/" class="external" target="_blank" rel="noopener noreferrer">Waveshare</a> e-paper display built +with the intention of learning about e-paper displays.</p> <video style="max-width:100%;" controls="" poster="thumb.png"> <source src="ereader.mp4" type="video/mp4" /> @@ -67,13 +67,13 @@ minimize power consumption when not in use and records the reading progress in the chip’s RTC memory.</p> <p>The most formidable challenge when trying to build an e-reader with an ESP32 -board is its limited memory and storage. My ESP-WROOM-32 board has 512 KB of -SRAM and 4 MB of flash memory, which the freeRTOS, ESP-IDF, and the e-reader +board is its limited memory and storage. My ESP-WROOM-32 board has 512KB of +SRAM and 4MB of flash memory, which the freeRTOS, ESP-IDF, and the e-reader application must share. To put things into perspective, a Kindle Paperwhite has -at least 256 MB of memory and 8 GB of storage.</p> +at least 256MB of memory and 8GB of storage.</p> <p>Despite its size, as microcontrollers go, ESP32 is a powerful system-on-a-chip -with a 160 MHz dual-core processor and integrated WiFi. So, I thought it’d be +with a 160MHz dual-core processor and integrated WiFi. So, I thought it’d be amusing to embrace the constraints and build my e-reader using a $5 MCU and the power of C programming.</p> @@ -86,7 +86,7 @@ monochrome image of a page (a .ebm file).</p> <p>The EBM file contains a series of bitmaps, one for each page of the book. The dimensions of each bitmap are equal to the size of the display. Each byte of the bitmap encodes information for rendering eight pixels. For my display, -which has a resolution of 480x800, the bitmaps are laid out along 48 KB +which has a resolution of 480x800, the bitmaps are laid out along 48KB boundaries. This simple file format lends well to HTTP streaming, which is its main advantage, as we will soon see.</p> @@ -95,20 +95,20 @@ PDF documents to EBM files.</p> <h2 id="how-does-it-work">How does it work?</h2> -<p>As the e-reader has no storage, it can’t store books locally. Instead, I first -have to upload the EBM file I want to read to a web server. The <code class="language-plaintext highlighter-rouge">EBM_ARCH_URL</code> -setting in the Kconfig.projbuild file points to the URL of the file. To read a -different book, I create an EBM file with the same name and upload it to the -original location. That way, I don’t have to modify the <code class="language-plaintext highlighter-rouge">EBM_ARCH_URL</code> value, -which requires recompiling the embedded software.</p> +<p>As the e-reader has no storage, it can’t store books locally. Instead, it +downloads pages of the EBM file over HTTP from the location pointed to by the +<code class="language-plaintext highlighter-rouge">EBM_ARCH_URL</code> setting in the Kconfig.projbuild file on demand. To read a +different book, we have to replace the old file with the new one or change the +<code class="language-plaintext highlighter-rouge">EBM_ARCH_URL</code> value. The latter requires us to recompile the embedded +software.</p> <p>Upon powering up, the e-reader checks the reading progress stored in the RTC memory. It then downloads three pages (current, previous, and next) to a -circular buffer in DMA-capable memory. When the user turns a page, one of the -microprocessor’s two cores transfers it from the buffer to the display over a -Serial Peripheral Interface (SPI). The other downloads a new page in the -background. I use the ESP-IDF task API to distribute the two tasks between the -available cores for maximum parallelism.</p> +circular buffer in DMA-capable memory. When the user turns a page by pressing a +button, one of the microprocessor’s two cores transfers it from the buffer to +the display over a Serial Peripheral Interface (SPI). The other downloads a new +page in the background. I used the ESP-IDF’s task API to distribute the two +tasks between the available cores to make the reader more responsive.</p> <p>I designed the EBM format with HTTP streaming in mind. Since the pages are laid out in the EBM file along predictable boundaries, the e-reader can request @@ -118,10 +118,16 @@ web server will process this request without custom logic.</p> <h2 id="reflections">Reflections</h2> <p>It’s been six years since the car park and the displays. I began this project -hoping to learn the low-level workings of e-paper displays. As a bonus, it led -me to explore some of ESP32’s most fascinating features: sleep modes, multicore -processing, DMA, and RTC memory. Embedded systems are magical things: invisible -particles swirl into form as the programmer whispers C.</p> +hoping to learn more about e-paper displays, and I got that and more. By +working within the constraints of the ESP32, I forced myself to explore some of +its advanced features: sleep modes, multicore task scheduling, DMA transfers, +and RTC memory.</p> + +<p>As for the prototype, while it’s no match for a commercial e-reader with +features like an offline library of books and touch screens, there’s something +to be said about reading on hardware you built yourself. You are no longer the +powerless Muggle watching others perform magic. You are the wizard who makes +the invisible particles swirl into form by whispering C to it.</p> <p>Files: <a href="source.tar.gz">source.tar.gz</a></p> </div> diff --git a/_site/projects/fpm-door-lock/index.html b/_site/projects/fpm-door-lock/index.html index 5170201..6256026 100644 --- a/_site/projects/fpm-door-lock/index.html +++ b/_site/projects/fpm-door-lock/index.html @@ -53,11 +53,11 @@ microcontroller.</p> <h2 id="overview">Overview</h2> -<p>The lock comprises three subsystems: the ATmega328P, an R503 fingerprint -sensor, and an FS5106B high-torque servo. The sensor mounted on the front -surface of the door enables users to unlock it from the outside. The servo is -attached to the interior door knob. The MCU must be installed at the back of -the door to prevent unauthorized users from tampering with it.</p> +<p>The lock comprises three subsystems: the ATmega328P microcontroller, an R503 +fingerprint sensor, and an FS5106B high-torque servo. The sensor mounted on the +front surface of the door enables users to unlock it from the outside. The +servo is attached to the interior door knob. The MCU must be installed at the +back of the door to prevent unauthorized users from tampering with it.</p> <p>When no one is interacting with the lock, the MCU is in deep sleep. The sensor and the servo each draw 13.8mA and 4.6mA of quiescent currents. To prevent this diff --git a/_site/projects/index.html b/_site/projects/index.html index 924dbad..95cbe6b 100644 --- a/_site/projects/index.html +++ b/_site/projects/index.html @@ -45,8 +45,8 @@ <td class="project-item"> - <img src="e-reader/thumb.png" alt="Prototype e-reader"> - <h5><a href="e-reader" class="link-decor-none">Prototype e-reader</a></h5> + <img src="e-reader/thumb.png" alt="Experimental e-reader"> + <h5><a href="e-reader" class="link-decor-none">Experimental e-reader</a></h5> </td> <td class="project-item"> @@ -18,7 +18,7 @@ title: About <h4>Navigation</h4> <ul> - <li>hme: Home page, listing latest articles.</li> + <li>hme: Home page, listing the latest articles.</li> <li>blg: Notes and tutorials about software and embedded systems.</li> <li>poc: Projects, prototypes, and experiments.</li> <li>abt: Site information.</li> |