{"id":226,"date":"2020-03-12T11:21:24","date_gmt":"2020-03-12T00:21:24","guid":{"rendered":"http:\/\/www.vk1zdj.net\/?p=226"},"modified":"2023-01-27T10:21:10","modified_gmt":"2023-01-26T23:21:10","slug":"the-world-of-raspberry-pi-clusters","status":"publish","type":"post","link":"http:\/\/www.vk1zdj.net\/?p=226","title":{"rendered":"The world of Raspberry Pi Clusters"},"content":{"rendered":"\n

(or – how to chuck a heap of computers into a small space… to do SDR functions.)<\/p>\n\n\n\n

So – One of my fellow Ham operators here in Canberra, Wade (VK1MIC) showed me a photo of his cluster of Pi computers connected to SDR dongles doing lots of interesting tasks, such as streaming audio from scanners, ADS-B, VHF WSPR, end lots of other stuff.<\/p>\n\n\n\n

I got excited, as I saw how useful these little Pi computers can be in the shack. It also reminded me of when I was building my own cluster, but hit a road block associated with how to sensibly mount the various boards without stuff lying all over the bench.<\/p>\n\n\n\n

A quick web surf later and I found an awesome case designed by C4 Labs, the Cluster case ( https:\/\/www.c4labs.com\/product\/8-slot-stackable-cluster-case-raspberry-pi-3b-and-other-single-board-computers-color-options\/<\/a> ) I liked the idea, but decided I needed to modify its height to allow the RTL-SDR dongle to be mounted inside the case. A couple of hours in front of the CAD software and laser cutter and I had an effective prototype.<\/p>\n\n\n\n

\"\"
First version of the a compute frame – I ended up making the tabs at the top of the board bigger to stop them snapping (Acrylic is finiky \ud83d\ude42 )<\/figcaption><\/figure>\n\n\n\n
\"\"
Pi Cluster case – Incorporating extra space for RTL SDR devices.<\/figcaption><\/figure>\n\n\n\n

When I designed the case, my focus was on making sure that the entire project was capable of running on 12V, so each card has a 12V -5V buck converter installed. I ran a bus system based on keyed 0.1 inch connectors that are easily available from Jaycar mounted on a strip of Veroboard.<\/p>\n\n\n\n

\"\"
View of the Power distribution bus.<\/figcaption><\/figure>\n\n\n\n

When I designed the frame supports, I was also careful to design a mount for a 2.5″ SDD, connected through a USB-SATA interface.<\/p>\n\n\n\n

I had to make some custom USB extension cables, so I used a Jaycar USB-A to USB-A bacle that I cut in half, and soldered a Jaycar USBA Socket (PS0924 – https:\/\/www.jaycar.com.au\/usb-type-a-pcb-mount-socket\/p\/PS0924<\/a> ) It was surprisingly simple to hand solder the cut cable onto the socket – I used a bit of heatshrink to protect it.<\/p>\n\n\n\n

The switch that I used is a secondhand Netgear GS108 – Is is a gigabit switch that can be run from 12V. I designed ample space at the bottom of the enclosure to allow installation.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Initially, I downloaded a standard version of Rasbian, and installed the standard SDR Shard software. Unfortunately, the result was terrible, with even WBFM Broadcast audio being jittery and blocky. So I searched for an alternate. I eventually found the amazing custom Pi Image developed by Luigi Freitas – PISDR ( https:\/\/pisdr.luigifreitas.me\/<\/a> ) Installing it was simple, and it worked beautifully.<\/p>\n\n\n\n

I have three cards installed at the moment, with space for two more and couple of SSDs. In all I’m pretty happy with the project so far.<\/p>\n\n\n\n

\"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

(or – how to chuck a heap of computers into a small space… to do SDR functions.) So – One of my fellow Ham operators here in Canberra, Wade (VK1MIC) showed me a photo of his cluster of… <\/p>\n","protected":false},"author":1,"featured_media":244,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false},"categories":[34],"tags":[],"jetpack_featured_media_url":"http:\/\/www.vk1zdj.net\/wp-content\/uploads\/2020\/02\/2020-03-11-21.47.24.jpg","_links":{"self":[{"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts\/226"}],"collection":[{"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=226"}],"version-history":[{"count":4,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts\/226\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts\/226\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/media\/244"}],"wp:attachment":[{"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=226"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=226"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=226"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}