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Airwave Inspector

Ryzen 7 cyberdeck boosted with Kraken SDR for mobile software radio fun powered by LiFePO4 batteries

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I like cyberdecks and the 2023 challenge gave me the excuse to resolve my issues with the Kraken SDR's reliance on the Raspberry Pi. Now you can take your deck on the go without resorting to ARM instruction sets!

This combines as many COTS hardware options as possible to make an off-the-shelf custom computer running a socketed Ryzen 7 APU. Everything is powered by a custom built LiFePO4 battery pack made of recycled cells.

**THIS PROJECT WILL CONTINUE TO BE IMPROVED BEYOND THE CHALLENGE DATE**

Power Supply

First the requirements:

DeviceVoltageLoad
PC
12V200W Max (~30W at idle)
Kraken SDR
12V/24V (USB)
12W
Screen5V (USB)
5W

Over-provisioning to 300W at 12V means I should expect to draw less than 25A, and at 24V just 13A.

Since I want to be able to charge quickly, 25A at 24V is also an ideal charging amperage.

The PowMr 60A MPPT charge controller can handle this easily, but it's bulky and it can only buck not boost. My friend and I are working on a replacement for this which has both buck and boost capacity in a wide voltage range. The PowMr can at least handle a wide voltage input for charging, for a 24V system it's 37V-105V. Additionally it can accept this from both a standard DC source, or from solar panels with MPPT charging.

To round things out, two USB PD Decoys in series will result in a 40V source that can feed the controller, which means I can use all those spare phone chargers I have laying around.

Power Storage

In order to support a higher charging amperage, 24v is just about the lowest voltage that seems reasonable. This gets us up over 550W which ensures I can always charge the battery at a good rate even under heavy load at the maximum provisioned 300W.

  • Sony 26650 US26650ft
    • When the cells are new they are 3000mah
    • Nominal voltage: 3.2V
    • Fully Charged Voltage: 3.65V
    • Fully Discharged Voltage: 2.5V
    • Max Continuous Discharge: 30A (10c)
    • Max Continuous Charge: 6A (2c)
  • 8S4P Battery Pack
    • Nominal Voltage: 25.6V
    • Fully Charged Voltage: 29.20V
    • Fully Discharged Voltage: 20.0V
    • Max Continuous Discharge: 120A
    • Max Continuous Charge: 24A

The battery pack is custom made using these used Sony cells and hooked in through a JiaBaiDa (JBD) BMS to protect the finished pack. The resulting pack has a nameplate capacity of about 300Wh, which is likely to last quite a long time doing simple tasks, but a but under an hour when doing something intense like running machine learning locally. The entire pack is wrapped in kapton tape to keep it in a nice solid unit.

Computer

Most cyberdeck builds are running raspberry pis, or some similar ARM based SBC.

Unfortunately a lot of the software for radio isn't compiled for ARM (which, obviously has a non-hardware solution), but even when it can be made to function, working with software such as RTL-SDR taxes most laptops, let alone SBC's. The solution? Make a maxxed out rig to take out into the field to run all sorts of radio goodies, with power to spare.

Additionally, there is the option to run local machine learning. While it might seem strange to want to do so locally, there are some quite valid reasons:

  • Live captions of radio conversations
  • Live captions to support a beginner stenographer at live speaker events
  • Transcription of recorded radio conversations for analysis and querying

Since radio is used in a lot of places where internet is unavailable, it may not be reasonable to farm out to a GPU cluster.

Radio

Thankfully Kraken SDR is a ready-made all-in-one board that gives me 5 RTL SDR boards, which is sufficient to listen to 2 or 3 P25 trunked systems at once, It just needs a 1A USB C input which can be provided by the USB power adapter. The data line is a separate USB C output that can be connected directly to the PC.

Cooling can be provided by using thermal pads to spread the heat out to nearby components, and allowing the fan airflow to cool the entire system as a whole.

panel-nw.3mf

File for printing

3mf - 87.79 kB - 08/15/2023 at 04:56

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panel-se.3mf

File for printing

3mf - 15.04 kB - 08/15/2023 at 04:56

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panel-ne.3mf

File for printing

3mf - 48.13 kB - 08/15/2023 at 04:56

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panel-sw.3mf

File for printing

3mf - 21.36 kB - 08/15/2023 at 04:56

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cyberdeck panel.FCStd

FreeCAD file of the whole panel

x-extension-fcstd - 2.20 MB - 08/15/2023 at 04:56

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  • 1 × Case, Hard-Sided, Harbor Freight, Apache 4800 In bold orange to dazzle the oppo's deckkers
  • 1 × Motherboard, Gigabyte, A520i AC A small, low cost motherboard that can handle the last generation of AM4 chips
  • 1 × PSU, MiniBox, PicoPSU-160-XT DC-DC 12v PSU (or upgrade to 400W https://www.amazon.com/dp/B082J1FBDH)
  • 1 × CPU, AMD, Ryzen 7 5700G The last generation of AM4 CPU, has onboard graphics capability, and thus ROCM https://www.amazon.com/dp/B091J3NYVF
  • 1 × CPU Cooler, Thermalright, AXP90-x36 Low profile cooler to fit in the tight confines https://www.amazon.com/dp/B0B66TYL2N

View all 27 components

  • Printer machine broke

    Andrea08/25/2023 at 04:13 0 comments

    I broke my 3D printer.

    The final revision of one of the mounts came unstuck and became a giant evil glob on the hotend, and when I removed it I severed all the wires to the thermocouple and heater!

    I do have my first drafts, however.

    Heres a pic of the test fit with the bracket system.

    TThe intention is to use adhesive to bond the printed parts to the case, then use heat set inserts and screws to mount the hardware to the brackets.

    This will keep everything in place and still allow me to get in and remove or replace things if that's needed.

    The photos show off the stack of boards one at a time so you can see the way it all fits together.

    I will try to modify the existing prints by hand somehow to work.

    Bare brackets
    The motherboard and the BMS installed
    Kraken installed "hot" side upwards (the side with the sdr chips, in the real deal there will be a thermal pad instead of kapton tape
    Charge controller, heat sink facing down
    24c to 12v converter not pictured as my heat insert tubes were too bulky and the heat sinks don't clear them. Bracket pictured, however, so use the power of imagination

  • Modeling the reorganization

    Andrea08/23/2023 at 04:47 0 comments

    Reorganization

    With the reorganization idea in full swing and literally every component removed I re-measured everything and created a simple cad mockup of each board's physical volume.

    I combined that, some Tetris skills, and 3 YouTube videos to calm the ADHD. The result?

    I decided to mount everything directly to the case except the voltage converter, which will mount to the top of the charge controller. 

    Files will be uploaded after I finish printing and do a test fit to make sure I didn't mess up with the calipers.

    Battery Take 3

    I admit I don't always think ahead far enough and I forgot that the BMS needs a wire to each cell to keep them balanced. I carefully slit open the pack casing and soldered new wire to each tab.

    I closed the whole thing up and now I have an extended balancing wire harness so that the BMS can be mounted with the power cables facing the battery instead of the cable harness ports.

  • Revise and rewrite

    Andrea08/22/2023 at 03:34 0 comments

    She's got a big rear end, and it holds her down.

    The whole case won't stand because the battery in the back is too heavy and makes the back want to lay flat, instead of lean open like a laptop.

    The solution? Move the battery.

    I'm moving the battery from the rear to the small front side flap of the case, aka the lid.

    I decided to take the opportunity to tear the battery down and re-pack it.

    Each "cell" is composed of 4 sony cells in parallel. Each Sony cell is wrapped in a 50¢ coin wrapper to prevent damage to the wrap. Each set of 4 is welded with nickel strip with excesses on one side, then wrapped in laptop tape.

    The excess tabs are then welded together, folded over, and taped. This is done one after another to form the final battery pack.

    The final pack is then wrapped in tape to provide just a little more structure.

    Stranded copper wire in silicone jacket is soldered to the excess tabs that make up the positive and negative leads of the pack.

  • White Box Action Shots

    Andrea08/15/2023 at 05:21 0 comments

    I don't have a fancy photography setup, so the closest I have is the white carpet under my white desk. So here's the worst action shots you've ever seen.

  • New Screen, New Face

    Andrea08/15/2023 at 05:18 0 comments

    Since the old screen was not cooperating, I went with what I could find on amazon with fast shipping, to make it to the deadline of the contest.

    Also because I really wanted to see it work.

    Unfortunately I spent 2 days trying to figure out why my system would boot up, show the BIOS logo and NOTHING ELSE. I was convinced that I had really messed something up, that I had shorted the board somewhere.

    After talking to some friends on discord, I decided to try a new pico PSU, just in case, which turned out to be... not needed at all. Anyone need one?

    It turns out the board shipped with firmware that couldn't handle the CPU, so one flash later and we're in business.

    I reprinted the faceplate, pretty much a total redesign for the screen portion with the rest left untouched. there's fewer vents in this version, but more holes, so I think it evens out. In any case the idea is that the intake fans feed the CPU cooler which acts as the output fan.

  • Test Fit With The Big Screen

    Andrea08/15/2023 at 05:14 0 comments

    This is the original screen I intended to use, powered by 12V DC and having a discrete controller board it seemed ideal.

    Unfortunately I could get this screen to light up and nothing else.

    I'll continue to troubleshoot it and will return to this setup if I can.

    You can see the first iteration of nylon "welding" which is actually quite strong.

    Additionally this is 1mm vent holes, which seemed too small so I bumped them up to 2mm for the next iteration.

    The PowMr screen didn't fit AT ALL and I had to hack at the hole to make it fit.

  • Trying the PowMr

    Andrea08/15/2023 at 05:09 0 comments

    I found out the hard way that the PowMr was not putting out a small regulated DC voltage like most MPPT controllers claim to, and the output was in fact the whole 25V of the battery pack.

    The cable for the screen for it is also wayyyy to short to make it out from behind my screen

  • Protoype 1 - Rough Fit

    Andrea08/15/2023 at 05:06 0 comments

    At this stage I believed I needed to isolate the load from the input charge voltage.

    I used three different voltage controllers, one for normal battery charging, one for the PC, and an entirely separate one for charging the battery over USB.

View all 8 project logs

  • 1
    Prepare Cells

    Start by charging all the cells up to their maximum capacity. Once they're all charged you can use a multimeter to sort the cells by their voltage, trying to minimize the differential for each set of parallel cells.

    Place each cell into a $1 paper coin sleeve to prevent shorting/rubbing/damage to the wrap.

  • 2
    Connect Cells

    Connect all cells in the 8 series - 4 parallel configuration using the nickle strip. Ideally use a spot welder to minimize cell damage.

    The BMS re-balancing and sensor wires can be attached to the nickle strip using a soldering iron.

    Appropriate wires can be connected to the positive and negative strips at each end of the pack in the same way.

  • 3
    Wrap Pack

    Use kapton tape to wrap the entire battery pack. Since the cells are inside paper coin sleeves, this shouldn't result in damage to the cell wrapping if it needs to be removed later.

    The kapton tape should keep everything together and electrically isolated, but still let heat through.

View all 13 instructions

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Discussions

Swampy wrote 08/23/2023 at 07:01 point

This is a superb project, love the tidy battery work and that for once someone did a cyberdeck without a RPI. Also cute keyboard i didn't know they made these with a pointer :)
Best of luck onwards!

  Are you sure? yes | no

Andrea wrote 08/23/2023 at 12:19 point

Thank you!

I left a link to the keyboard in the components list if you want one. I originally was looking for a way to adapt a thinkpad keyboard but then I saw they made a standalone version.

I like the rpi but I do feel it's been done to death. I hope this will inspire people to do some cyberdeck maximalism.

This is my first battery!

  Are you sure? yes | no

Swampy wrote 08/24/2023 at 11:34 point

Awesome, thank you for the keyboard link, I only wish they made it in ISO format :P.

On the note of maximalist cyberdecks, I was looking into luggable computers like the Sharp PC-7000 and will compile a BOM for the project if I can get a hold of some small 10" OLED screens localy here.
By chance, do you have a link to the BMS that you used?

  Are you sure? yes | no

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