From fa2d2df753da5320a9334ba7398f32609bd19a15 Mon Sep 17 00:00:00 2001
From: Sadeep Madurange <sadeep@asciimx.com>
Date: Wed, 10 Dec 2025 21:25:04 +0800
Subject: Improve e-reader write up.

---
 _site/projects/e-reader/index.html | 48 +++++++++++++++++++++-----------------
 _site/projects/index.html          |  4 ++--
 2 files changed, 29 insertions(+), 23 deletions(-)

(limited to '_site/projects')
diff --git a/_site/projects/e-reader/index.html b/_site/projects/e-reader/index.html
index 5fe3341..9d26ee2 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" />
@@ -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/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">
-- 
cgit v1.2.3

