The WORKBENCH part 5

Looks like the latest Microchip MPLAB ICE 4 emulator, programmer, debugger is out and available in stock with latest IDE support available for download if interested (AVR, SAMD users et al)


Think I’ve just found the idea power supply for my next LoRaWAN GPS Tracker development:


Now how can this be adapted/adopted to support remotely deployed RPi based gw’s? Main weakness is vulnerability for SD card corruption, usually during uncontrolled power out, so if this could help fix…? :thinking:

Pity it’s only Pi 4 onwards…to many 2b/3b+ & 0Ws deployed so far… (less power draw than Pi4’s)…

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Only if they are on a network as they have to download ~1Gb as a minimum - although could be via LTE but it has to be an external network to the Pi as it can’t do anything until it’s installed.

It would also need to be able to detect a corrupt SD Card and trigger a refresh - bit hard to do if the OS is borked - but a watchdog could intervene - but it would be a sophisticated watchdog with a network - maybe another Pi?

Perhaps you could create a spec for a remote setup so we can have an alternative to Balena and then the community could come together to create a solution …

Academic at present but stock coming mid March …

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How about using CM4 with eMMC on Sourcekit PiTray Mini. No more corrupt SDcards. Combined with balena a winning combination.

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Have you hacked my file server??

But still largely Unobtainium - the challenge I have is not investing in a 100 or so of all the bits I could buy as they become available before I’ve got a design. Perhaps the first step is to get a group buy scheme of all the things we’d like to have on hand.

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Not on my workbench - the Microchip LDO I’ve designed in to a pile of boards and just run out of - or the 8 pin PIC we use in our security timer products. Two and a half hours of finding alternatives …

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No, I’ve deployed a couple of these combinations with a concentrator card == gateway.

Currently waiting for more CM4 with eMMC. Initial delivery when ordered last year was march, by now pushed back to mid august. Seeed had some in stock but those were top end model when the simplest is sufficient and I refuse to pay triple.

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Hi everyone!

I just constructed a small holder for the Browan TABS sensors, so you do not have to glue them somewhere. Now its easier to replace the battery for example or move them around. Its a OpenSCAD file so you can adjust a number of things, like want to use glue/screw/magnets to hold it to the wall/surface, need a bit of height adjustment for the door/window sensor to get good connection to the magnet? Its just customizeable. You can find the files here:

And a picture from a installation with height adjustment:
2022-02-14 12.17.19

Have fun with it, its under CC-BY-SA


After a long wait finally received Raspi 0W Mk2 - just in time for another low power GW build as update to previous 0W MK1 ‘Owls’… so approriate that its…



Looks very interesting, especially given the ongoing shortage in chips of all kinds.

Have you published anything from this project? I tried to find something (Gerber files, source code) but didn’t find anything.

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Yes, you’ll see in my post the PCB I used, the wiring diagram and all the details for the source code I used …

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How did your Z2W gateway work out @Jeff-UK ?

I have a RPi Zero W gateway using @Charles interface PCB/RAK831 and code from his repo and it is super robust. I also have a RPi Zero2 W whch uses Balena ‘Basic Station’ and a RAK831 radio also. There were a couple of bugs in this that prevented the software from generating TTN credentials from MAC address on boot but Balena (Marc) were pretty dynamic in fixing this, works an absolute charm now and is super easy to support with the default tunnel etc in Balena.

What is the spec of your low power gateway? I should test both of mine for power shouldn’t I? Neither are deployed in ‘working’ scenarios but would appear suitable.


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Such is the state of the Unobtainium Vortex and it’s capture of any reasonable priced MCU in its evil grasp, Adafruit have started a new YouTube feature:


Life in the old 8-bit work horses yet! (Pair with a COTS LoRaWAN module so you don’t have to play SW eng and wrangle a critical s/w stack…… simples :slight_smile: )

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MVIO on the AVR-DD parts is useful - but what would be more useful would be for them to make more of the recent parts that are completely Unobtainium - like the megaAVR 0-series. Plus some of the venerable but super useful SAMD21.

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Wireless update to RPi Pico….and Eben claims not made from Unobtainium so need to think of some use cases…. :wink: Could be a nice update for a PAX counter type device?

Maybe, but it’s WiFi, not LoRa …

Usual pax counters sniff for peoples BT &/or WiFi radios as a proxy for # of bodies - an indicator vs actual count. Then send count data over LoRa :slight_smile: For privacy its not usually considered good to capture the MAC’s for long term storage centrally so some level of edge processing can be a good thing - repeat visitor detection, data extraction, duration/location ‘dwell’ time evaluation etc. good for monitoring people & traffic flows, congestion analysis, popularity eval, etc.

Another interesting snippet given choice of WiFi solution (CYW43439 from Infineon):

CYW43439 supports both Bluetooth Classic and Bluetooth Low-Energy – we have not enabled Bluetooth on Pico W at launch, but may do so in the future.

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