https://rfcorner.in/tags/kicad/Recent content in KiCad on Dhiru's NotebookHugoenSat, 07 Feb 2026 00:00:00 +0000https://rfcorner.in/posts/simplest-aprs-digipeater-igate-on-mcu/Sat, 07 Feb 2026 00:00:00 +0000https://rfcorner.in/posts/simplest-aprs-digipeater-igate-on-mcu/<h2 id="description">Description</h2> <p>We have built the simplest, power-efficient and 'ready-for-solar' APRS Digipeater and iGate on an MCU (RPi Pico 2 W)!</p> <p><img alt="KISSLink v1 Render" loading="lazy" src="https://rfcorner.in/images/KISSLink-v1-7.png"></p> <p>Our existing <code>KISSLink v1 BLE KISS TNC</code> device is capable of running in standalone mode with an alternate firmware!</p> <p>Goal(s): Our design prioritizes low power, reliability, and unattended deployment over flexibility.</p> <p>And yes, we want to do this with cheap, widely available BaoFeng radios. This means a couple of things:</p>https://rfcorner.in/posts/aprs-interface-v2/Thu, 29 Jan 2026 00:00:00 +0000https://rfcorner.in/posts/aprs-interface-v2/<h2 id="description">Description</h2> <p>We have built a Bluetooth-enabled and APRSdroid-compatible digital interface (KISS TNC) for less than 15 USD (for the fully-loaded make including cables). We call it the KISSLink v1.</p> <p><img alt="KISSLink v1" loading="lazy" src="https://rfcorner.in/images/aprsdroid-3.jpg"></p> <p><img alt="KISSLink v1 Render" loading="lazy" src="https://rfcorner.in/images/KISSLink-v1-7.png"></p> <p>This digital interface can be powered from the USB 5V or the inbuilt battery.</p> <h2 id="schematic">Schematic</h2> <div class="embed-pdf-container" id="embed-pdf-container-f1c39fe8"> <div class="pdf-loadingWrapper" id="pdf-loadingWrapper-f1c39fe8"> <div class="pdf-loading" id="pdf-loading-f1c39fe8"></div> </div> <div id="overlayText"> <a href="https://rfcorner.in/pdfs/KISSLink-v1.pdf" aria-label="Download" download> <svg aria-hidden="true" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 18 18"> <path d="M9 13c.3 0 .5-.1.7-.3L15.4 7 14 5.6l-4 4V1H8v8.6l-4-4L2.6 7l5.7 5.7c.2.2.4.3.7.3zm-7 2h14v2H2z" /> </svg> </a> </div> <canvas class="pdf-canvas" id="pdf-canvas-f1c39fe8"></canvas> </div> <div class="pdf-paginator" id="pdf-paginator-f1c39fe8"> <button id="pdf-prev-f1c39fe8">Previous</button> <button id="pdf-next-f1c39fe8">Next</button> &nbsp; &nbsp; <span> <span class="pdf-pagenum" id="pdf-pagenum-f1c39fe8"></span> / <span class="pdf-pagecount" id="pdf-pagecount-f1c39fe8"></span> </span> <a class="pdf-source" id="pdf-source-f1c39fe8" href="https://rfcorner.in/pdfs/KISSLink-v1.pdf">[pdf]</a> </div> <noscript> View the PDF file <a class="pdf-source" id="pdf-source-noscript-f1c39fe8" href="https://rfcorner.in/pdfs/KISSLink-v1.pdf">here</a>. </noscript> <script type="text/javascript"> (function(){ var url = '\/pdfs\/KISSLink-v1.pdf'; var hidePaginator = "" === "true"; var hideLoader = "true" === "true"; var selectedPageNum = parseInt("") || 1; var pdfjsLib = window['pdfjs-dist/build/pdf']; if (pdfjsLib.GlobalWorkerOptions.workerSrc == '') pdfjsLib.GlobalWorkerOptions.workerSrc = "https:\/\/rfcorner.in\/" + 'js/pdf-js/build/pdf.worker.js'; var pdfDoc = null, pageNum = selectedPageNum, pageRendering = false, pageNumPending = null, scale = 3, canvas = document.getElementById('pdf-canvas-f1c39fe8'), ctx = canvas.getContext('2d'), paginator = document.getElementById("pdf-paginator-f1c39fe8"), loadingWrapper = document.getElementById('pdf-loadingWrapper-f1c39fe8'); showPaginator(); showLoader(); function renderPage(num) { pageRendering = true; pdfDoc.getPage(num).then(function(page) { var viewport = page.getViewport({scale: scale}); canvas.height = viewport.height; canvas.width = viewport.width; var renderContext = { canvasContext: ctx, viewport: viewport }; var renderTask = page.render(renderContext); renderTask.promise.then(function() { pageRendering = false; showContent(); if (pageNumPending !== null) { renderPage(pageNumPending); pageNumPending = null; } }); }); document.getElementById('pdf-pagenum-f1c39fe8').textContent = num; } function showContent() { loadingWrapper.style.display = 'none'; canvas.style.display = 'block'; } function showLoader() { if(hideLoader) return loadingWrapper.style.display = 'flex'; canvas.style.display = 'none'; } function showPaginator() { if(hidePaginator) return paginator.style.display = 'block'; } function queueRenderPage(num) { if (pageRendering) { pageNumPending = num; } else { renderPage(num); } } function onPrevPage() { if (pageNum <= 1) { return; } pageNum--; queueRenderPage(pageNum); } document.getElementById('pdf-prev-f1c39fe8').addEventListener('click', onPrevPage); function onNextPage() { if (pageNum >= pdfDoc.numPages) { return; } pageNum++; queueRenderPage(pageNum); } document.getElementById('pdf-next-f1c39fe8').addEventListener('click', onNextPage); pdfjsLib.getDocument(url).promise.then(function(pdfDoc_) { pdfDoc = pdfDoc_; var numPages = pdfDoc.numPages; document.getElementById('pdf-pagecount-f1c39fe8').textContent = numPages; if(pageNum > numPages) { pageNum = numPages } renderPage(pageNum); }); })(); </script> <h2 id="rx-path-simulation-af-front-end">RX path simulation (AF front-end)</h2> <p><img alt="KISSLink v1 Simulation TX" loading="lazy" src="https://rfcorner.in/images/KISSLink-Sim-TX-1.png"></p>https://rfcorner.in/posts/aprs-interface/Sat, 17 Jan 2026 00:00:00 +0000https://rfcorner.in/posts/aprs-interface/<h2 id="design">Design</h2> <p>Here is a "safe" APRS interface for BaoFeng and other radios.</p> <p>Sample schematic:</p> <div class="embed-pdf-container" id="embed-pdf-container-7475f967"> <div class="pdf-loadingWrapper" id="pdf-loadingWrapper-7475f967"> <div class="pdf-loading" id="pdf-loading-7475f967"></div> </div> <div id="overlayText"> <a href="https://rfcorner.in/pdfs/TheDigitalInterface-2026.pdf" aria-label="Download" download> <svg aria-hidden="true" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 18 18"> <path d="M9 13c.3 0 .5-.1.7-.3L15.4 7 14 5.6l-4 4V1H8v8.6l-4-4L2.6 7l5.7 5.7c.2.2.4.3.7.3zm-7 2h14v2H2z" /> </svg> </a> </div> <canvas class="pdf-canvas" id="pdf-canvas-7475f967"></canvas> </div> <div class="pdf-paginator" id="pdf-paginator-7475f967"> <button id="pdf-prev-7475f967">Previous</button> <button id="pdf-next-7475f967">Next</button> &nbsp; &nbsp; <span> <span class="pdf-pagenum" id="pdf-pagenum-7475f967"></span> / <span class="pdf-pagecount" id="pdf-pagecount-7475f967"></span> </span> <a class="pdf-source" id="pdf-source-7475f967" href="https://rfcorner.in/pdfs/TheDigitalInterface-2026.pdf">[pdf]</a> </div> <noscript> View the PDF file <a class="pdf-source" id="pdf-source-noscript-7475f967" href="https://rfcorner.in/pdfs/TheDigitalInterface-2026.pdf">here</a>. </noscript> <script type="text/javascript"> (function(){ var url = '\/pdfs\/TheDigitalInterface-2026.pdf'; var hidePaginator = "" === "true"; var hideLoader = "true" === "true"; var selectedPageNum = parseInt("") || 1; var pdfjsLib = window['pdfjs-dist/build/pdf']; if (pdfjsLib.GlobalWorkerOptions.workerSrc == '') pdfjsLib.GlobalWorkerOptions.workerSrc = "https:\/\/rfcorner.in\/" + 'js/pdf-js/build/pdf.worker.js'; var pdfDoc = null, pageNum = selectedPageNum, pageRendering = false, pageNumPending = null, scale = 3, canvas = document.getElementById('pdf-canvas-7475f967'), ctx = canvas.getContext('2d'), paginator = document.getElementById("pdf-paginator-7475f967"), loadingWrapper = document.getElementById('pdf-loadingWrapper-7475f967'); showPaginator(); showLoader(); function renderPage(num) { pageRendering = true; pdfDoc.getPage(num).then(function(page) { var viewport = page.getViewport({scale: scale}); canvas.height = viewport.height; canvas.width = viewport.width; var renderContext = { canvasContext: ctx, viewport: viewport }; var renderTask = page.render(renderContext); renderTask.promise.then(function() { pageRendering = false; showContent(); if (pageNumPending !== null) { renderPage(pageNumPending); pageNumPending = null; } }); }); document.getElementById('pdf-pagenum-7475f967').textContent = num; } function showContent() { loadingWrapper.style.display = 'none'; canvas.style.display = 'block'; } function showLoader() { if(hideLoader) return loadingWrapper.style.display = 'flex'; canvas.style.display = 'none'; } function showPaginator() { if(hidePaginator) return paginator.style.display = 'block'; } function queueRenderPage(num) { if (pageRendering) { pageNumPending = num; } else { renderPage(num); } } function onPrevPage() { if (pageNum <= 1) { return; } pageNum--; queueRenderPage(pageNum); } document.getElementById('pdf-prev-7475f967').addEventListener('click', onPrevPage); function onNextPage() { if (pageNum >= pdfDoc.numPages) { return; } pageNum++; queueRenderPage(pageNum); } document.getElementById('pdf-next-7475f967').addEventListener('click', onNextPage); pdfjsLib.getDocument(url).promise.then(function(pdfDoc_) { pdfDoc = pdfDoc_; var numPages = pdfDoc.numPages; document.getElementById('pdf-pagecount-7475f967').textContent = numPages; if(pageNum > numPages) { pageNum = numPages } renderPage(pageNum); }); })(); </script> <h2 id="render">Render</h2> <p><img alt="TheDigitalInterface-2026" loading="lazy" src="https://rfcorner.in/images/TheDigitalInterface-2026.png"></p>https://rfcorner.in/posts/writing-test-cases-for-pcbs/Fri, 07 Nov 2025 00:00:00 +0000https://rfcorner.in/posts/writing-test-cases-for-pcbs/<p>This note demonstrates a small <code>connectivity tester</code> / <code>check nets</code> program for KiCad. This program allows doing checks like: Is the <code>U1:8</code> pin connected to <code>GND</code>?</p> <h2 id="motivation">Motivation</h2> <p>Sometimes visual errors can creep in the schematic (and the PCB subsequently). This <code>connectivity tester</code> allows expressing the same connections in a non-visual way (with a different probability of making errors).</p> <p>The ERC and DRC checks in KiCad work great but this non-visual test assertions provide another level of sanity checking.</p>