3D Printed Raspberry Pi Rack Mount with Heat-sink (Passive Cooling)

With now 6 Raspberry Pis lying (hanging) around inside and around my server rack I’ve started to look for a nice and clean way to mount them in my server rack. On thingiverse I’ve seen a few 3D printed Raspberry Pi brackets and I immediately liked the idea; but as I wanted a simple design with the ability to add a heat sink, I had to start from scratch. Also, at the time I started the design, there weren’t any brackets for the newest Raspberry Pi 4. So, the result of my effort can be seen here:

After a about half a dozen iterations over the last two months, the following 3D print is ready to be equipped with heat sinks and mounted in my server rack:

I’ve prepared two versions of the RasPi Rack holder, one for the the older Raspberry Pi 3 Model and one for the Rasperry Pi 4. The STL files for 3D printing are available for download and licensed under CC-BY-SA 4.0: RasPi_RackMount.zip

The heat sink was bought on ebay (link) and is the upper half of a passive cooled aluminium Raspberry Pi case.

The 2 HE rack panel was bought at Musicstore.de, but I’ve also seen them on ebay and Amazon. They also sell small panels to cover 1 or 2 empty slots, if necessary. The 2 HE panel can take up to 10 modules (i.e. Raspberry Pis).

The RasPi’s are currently all powered from the back side, each with their own power supply. I’m currently planning on inserting a 5x USB charger into one of the module slots to power up to five at the same time.

Whoopsie…

I’ve just seen how much time has passed since I’ve updated my website. Time to add a few projects I’ve been working on over the last yearā€¦

Got my Hands on a few dozen Fidget Spinners…

Got a few fidget spinners that were sorted out due to defects. Repaired most of them an played a little with them. In the end I did not have any use for a few dozen figet spinners so I donated them to a charity tombola…

But I kept a few of the LED circuits… just because they were blinking… you know…

PONG… I’m online and answering again…

I did not post anything for quite a while… we bought a house and moved into it. This consumed most of my spare time and my ‘hacking capabilities’ during the last few months. But the good news is: I’ve now got a whole room in the cellar which I’m currently turning into a hacker lair / electronics shop without having to care too much about the the WAF.

I just just returned from a business trip to the US and wanted to ‘report back’ with a nightly impression of New York / Manhattan. (Please forgive the low quality as the photo was taken with my smartphone from the airplane window.)

KiCad Design Files for the LH5801 Sharp Microprocessor

I’m currently working on a custom development board, based on a quarter of a century old microprocessor, the Sharp LH5801. This microprocessor is the heart of the Sharp PC-1500(A) Pocket Computer, also known as Tandy TRS-80 Model II.

I’ve got plenty of documentation on the processor and the Sharp PC-1500, but what I did not have was a spare processor to play with. Recently, I got hold of a dozen of them, so no excuse anymore for not playing with them. šŸ™‚

I started the design process by measuring out the package sizeĀ in mm and wondered about the strange results I got… Well the size of LH5801 package is – bang on – 0.7 inches. It also has an odd number of pins for such a package size: 76 pins. Both make it pretty impossible to use the standard footprints provided by various package libraries. At least a short round of googling for packages for Eagle CAD or KiCad was unsuccessful.

So I had to design my own footprint which was smoother than expected. I used a already present layout with the correct footprint pitch and adapted copied/adapted the pins.

The part was made with KiPart (based on a CVS table). Ā The pin description and layout was taken from the Sharp PC-1500 Technical Reference Manual.

The resulting KiCad part and footprint is in my Sharp PC KiCad Library at GitHub.

KVM over IP Switch: Cross-vendor Firmware Upgrade via hidden Option adds VNC Server

At work we have a KVM over IP switch from Inter-Tech, a KVM IP-KVM101. It is really a small and versatile device that,Ā in combination with 16-port KVM switches, allows us to control a complete rack with test hardware.

The KVM switch provides a web interface with a Java Web Start applicationĀ for remote access. ButĀ the latest browser security updates disabled and removed theĀ Java Web Start supportĀ . This move was announced quite someĀ time ago (Oracle White Paper). Still, the vendor of the KVM switch, Inter-Tech, was not able to provide a valuableĀ solution toĀ cope with this problem.

After a bit of Googling I found an AmazonĀ reviewĀ aboutĀ this particular KVM switch where the reviewer stated to have installedĀ the firmware from another brand, the LINDY KVM over IP Switch. The LINDY switch looks identical (besides a different sticker) and – even better – their latest firmware provides a VNC server. This would allow us a browser and even operating system independent access to the KVM.
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