{"id":460,"date":"2026-01-15T14:18:19","date_gmt":"2026-01-15T13:18:19","guid":{"rendered":"https:\/\/ca.rstenpresser.de\/blag\/?p=460"},"modified":"2026-01-15T18:29:58","modified_gmt":"2026-01-15T17:29:58","slug":"stonehenge-soldering-challenge","status":"publish","type":"post","link":"https:\/\/ca.rstenpresser.de\/blag\/2026\/01\/stonehenge-soldering-challenge\/","title":{"rendered":"Stonehenge soldering challenge"},"content":{"rendered":"\n<figure class=\"wp-block-video\"><video controls src=\"http:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/stonehenge-video.mp4\"><\/video><figcaption class=\"wp-element-caption\">Video of the Stonehenge PCB in action<\/figcaption><\/figure>\n\n\n\n<p>During one of those evenings in the <strong>#CCCAC<\/strong> hackerspace talking about stuff and shitposting the concept of stacking components like a tori was discussed, and shortly after that the idea of the Stonhenge PCB was born. It is not quite clear who and how came up with it, but I liked the idea and decided to start working on it. It sure makes a <s>good<\/s> cursed soldering challenge.<\/p>\n\n\n\n<p>The PCB design was done in <a href=\"https:\/\/kicad.org\">KiCad<\/a>, modifying existing footprints and their 3D models to get a nice preview. The position and size of the stones were extracted from a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Stonehenge#\/media\/File:Stone_Plan.jpg\">drawing on wikipedia<\/a>. Turns our every stone has a name\/number, so I did reuse them in the PCB design to keep things simple. The whole project lives in a <a href=\"https:\/\/gitlab.aachen.ccc.de\/cpresser\/stonehenge\">git repository<\/a>, check it out if you want to look at more details.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"881\" height=\"737\" src=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image.png\" alt=\"Screenshot from KiCad showing the PCB design with the drawing overlayed \" class=\"wp-image-462\" srcset=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image.png 881w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-300x251.png 300w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-768x642.png 768w\" sizes=\"(max-width: 881px) 100vw, 881px\" \/><\/figure>\n\n\n\n<p>Because everything needs LEDs, the &#8216;top&#8217;-stones are downward facing LEDs.<\/p>\n\n\n\n<p>The board outline is a rhombus shape inspired by artifacts from the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Bell_Beaker_culture\">Bell Beaker culture<\/a> which is related to the construction of Stonehenge. The silkscreen and copper artwork (which I did not do myself &#8211; it was gifted by friends) also draws inspiration from neolithic items. <\/p>\n\n\n\n<p>I made kits of this project that were available at <strong>#HardwareHackingArea<\/strong> at the dutch hackercamp #WHY2025 and during the #39c3 congress. The earlier #WHY2025 kit was very rushed and had some small issues. There are differences to the latest version &#8211; for details check the <a href=\"https:\/\/gitlab.aachen.ccc.de\/cpresser\/stonehenge\/-\/blob\/main\/README.md?ref_type=heads\">README<\/a> in the <a href=\"https:\/\/gitlab.aachen.ccc.de\/cpresser\/stonehenge\">git project<\/a>. The kit has all the parts required and a nice 3D-printed base for the PCB and temporary parts storage. <\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"622\" height=\"575\" src=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-1.png\" alt=\"top down image of the cradle containing all the parts of the kit. They are annotated with text.\" class=\"wp-image-463\" style=\"width:840px;height:auto\" srcset=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-1.png 622w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-1-300x277.png 300w\" sizes=\"(max-width: 622px) 100vw, 622px\" \/><figcaption class=\"wp-element-caption\">A single cradle with neatly arranged and labeled components <\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251217_130937-1024x768.jpg\" alt=\"\" class=\"wp-image-466\" srcset=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251217_130937-1024x768.jpg 1024w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251217_130937-300x225.jpg 300w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251217_130937-768x576.jpg 768w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251217_130937-1536x1152.jpg 1536w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251217_130937-2048x1536.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Colorful 3D printed cradles filled with a assortment of SMT components<\/figcaption><\/figure>\n\n\n\n<p>The #39c3 kits were partially sponsored by <a href=\"https:\/\/pcbway.com\">PCBWay<\/a>. Interestingly enough they did contact me via this blog and offered to sponsor some PCBs. I took that offer since I was about to order PCBs for this project anyway. The earlier version for WHY2025 was made by JLC, and the prototypes were ordered on <a href=\"https:\/\/aisler.net\/de\">aisler<\/a>. Here is a side-by side comparison of the 3 variants. Can you guess which one is which?<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"356\" src=\"http:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251201_193555_smol-1024x356.jpg\" alt=\"Side by side view of 3 mostly identical PCBs\" class=\"wp-image-464\" style=\"width:840px;height:auto\" srcset=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251201_193555_smol-1024x356.jpg 1024w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251201_193555_smol-300x104.jpg 300w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251201_193555_smol-768x267.jpg 768w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251201_193555_smol-1536x534.jpg 1536w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20251201_193555_smol-2048x712.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<ul>\n<li>Left: <strong>PCBWay<\/strong><\/li>\n\n\n\n<li>Center: Aisler<\/li>\n\n\n\n<li>Right: JLC<\/li>\n<\/ul>\n\n\n\n<p>I am really happy with the sponsored boards. They look excellent, the solder mask is &#8216;less green&#8217; than on the others, which gives a better contrast with the parts and looks a little better with the LEDs turned on. PCBWay sure did a nice job, shipping was also fast and I had no issues with customs\/import taxes.<\/p>\n\n\n\n<p>Apparently the kit was a success at #39c3, all 65 of them were handed out to hackers which had fun assembling them. Unfortunately the success rate was not good, there was not enough time to finish for most people and its not the best environment for such a challenging soldering job &#8211; especially when you are trying to learn doing tiny and unusual joints. While a experienced (and fast) person can assemble both sides in about 30-45minutes, a hacker that is new to this will surely need more than 2-3 hours. The workshop was only 2h30min, any longer also would be bad. Most people can&#8217;t concentrate for that long. So I am considering making it easier: the next iteration will at least have a different USB-Socket which has less pins with more spacing.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"769\" src=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-2-1024x769.png\" alt=\"A somewhat messy table. lots of soldering irons, wires, tweezers, a microscope, instruction manuals and various other tools. \nThe hands of 4 people working on the stonehenge board can be seen.\" class=\"wp-image-465\" srcset=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-2-1024x769.png 1024w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-2-300x225.png 300w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-2-768x577.png 768w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-2.png 1156w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">A table at #HardwareHackingArea during the workshop<\/figcaption><\/figure>\n\n\n\n<p>The software utilizes the <a href=\"https:\/\/github.com\/cnlohr\/ch32fun\">ch32fun<\/a> framework by <strong>cnlohr<\/strong>, the original code was written by <a href=\"https:\/\/github.com\/casartar\/Stonehenge-fw\">Casartar<\/a> during WHY2025. It has evolved a little since and now does proper PWM charlieplexing of the LEDs. The <strong>RISC-V<\/strong> toolchain is reasonably accessible (at least on my ubuntu based linux machine). Together with the <a href=\"https:\/\/github.com\/frank-zago\/isp55e0\">isp55e0<\/a> bootloader one can upload software without the use an extra hardware interface. <\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"902\" src=\"http:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20260110_222230-1024x902.jpg\" alt=\"3 milled pieces, two brass and one aluminium\" class=\"wp-image-470\" srcset=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20260110_222230-1024x902.jpg 1024w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20260110_222230-300x264.jpg 300w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20260110_222230-768x676.jpg 768w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20260110_222230-1536x1353.jpg 1536w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/IMG_20260110_222230-2048x1804.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Milled Cradle<\/figcaption><\/figure>\n\n\n\n<p>Because I can, I also made one cradle from brass. To practice I also made one from aluminium (brass is rather expensive), its weight feels identical to the 3D-print. The brass is quite heavy, it gives a totally different feeling when you are holding it. All of them were milled on the desktop CNC machine in the <a href=\"https:\/\/ccc.ac\">CCCAC<\/a> hackerspace. Since the crade was modeled in <a href=\"https:\/\/freecad.org\">FreeCAD<\/a> it was only logical to also make the toolpaths in FreeCAD.<\/p>\n\n\n\n<figure class=\"wp-block-gallery has-nested-images columns-default is-cropped wp-block-gallery-2 is-layout-flex wp-block-gallery-is-layout-flex\">\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"538\" height=\"702\" data-id=\"472\" src=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-3.png\" alt=\"\" class=\"wp-image-472\" srcset=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-3.png 538w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-3-230x300.png 230w\" sizes=\"(max-width: 538px) 100vw, 538px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1025\" height=\"712\" data-id=\"475\" src=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-6.png\" alt=\"\" class=\"wp-image-475\" srcset=\"https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-6.png 1025w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-6-300x208.png 300w, https:\/\/ca.rstenpresser.de\/wp-files\/2026\/01\/image-6-768x533.png 768w\" sizes=\"(max-width: 1025px) 100vw, 1025px\" \/><\/figure>\n<\/figure>\n\n\n\n<p><\/p>\n\n\n\n<p><strong>I want to thank all the people that have helped making this project a success<\/strong>!<\/p>\n\n\n\n<ul>\n<li>The CCCAC hacker-space for somehow coming up with the idea as a shitpost <\/li>\n\n\n\n<li>The anonymous person that donated the artwork <\/li>\n\n\n\n<li>Casartar for helping with debugging, bring up and making the STM32 firmware<\/li>\n\n\n\n<li>All the friends that helped with component selection, 3D-Printing and encouragement <\/li>\n\n\n\n<li>The people that helped kitting (making kits by sorting and counting components)<\/li>\n\n\n\n<li>Workshop participants<\/li>\n\n\n\n<li>All the HardwareHackingArea people<\/li>\n\n\n\n<li>PCBWay for sponsoring the boards for the #39c3 workshop<\/li>\n\n\n\n<li>The authors, maintainers and contributors of all the open source software used <\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>During one of those evenings in the #CCCAC hackerspace talking about stuff and shitposting the concept of stacking components like a tori was discussed, and shortly after that the idea of the Stonhenge PCB was born. It is not quite clear who and how came up with it, but I liked the idea and decided &hellip; <a href=\"https:\/\/ca.rstenpresser.de\/blag\/2026\/01\/stonehenge-soldering-challenge\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Stonehenge soldering challenge<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":471,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[116,175],"tags":[11,156,177,176],"_links":{"self":[{"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/posts\/460"}],"collection":[{"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/comments?post=460"}],"version-history":[{"count":10,"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/posts\/460\/revisions"}],"predecessor-version":[{"id":485,"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/posts\/460\/revisions\/485"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/media\/471"}],"wp:attachment":[{"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/media?parent=460"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/categories?post=460"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ca.rstenpresser.de\/blag\/wp-json\/wp\/v2\/tags?post=460"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}