Thomas Jensen

TL;DR: Winter-Thomas needs to stop writing checks that summer-Thomas has to cash — especially when summer-Thomas would rather be outside than rebuilding a broken Ceph cluster in the basement.

https://www.cavelab.dev/posts/simplicity-is-king/

#simplicity

After two years of #roadtripping in #Norway, first with Airbnb and then tenting — we have bought a teardrop #camper; A #HeroCamper 😀

With a rooftop tent on the car and a rooftop tent on the trailer, we have three bedrooms with sleeping space for six people.

It's a pretty awesome looking things, with lots of clever solutions. We named it Rulle (Norwegian for Rolly).

https://www.cavelab.dev/posts/rulle-ranger/

#camping

And here is the blog post. I write about the differences between the old and new #keypad, and the alarm panel implementation in my #RaspberryPi #Python alarm system code.

https://blog.cavelab.dev/2026/01/rpi-alarm-keypads/

Here is a demonstration video of the new #keypad in action, using both PIN and RFID.

https://iframe.mediadelivery.net/play/175117/990b7b3e-5df4-4445-b433-a39481eca151

On my #RPiSecuritySystem — I started with a simple #Zigbee #keypad that could only send actions. I have later replaced it with a more advanced one, that can also receive states and supports RFID. (And looks much cooler) 🤓

I am working on a blog post to explain how it is integrated with my system.

It's been three years since I last posted about my #RaspberryPi security alarm project. The project is alive and well, constantly developed, and used daily.

Here is my attempt at breaking the writer's block and get it documented:

https://blog.cavelab.dev/2025/12/rpi-diy-alarm-update/

#RPiSecuritySystem

Lots of things changed in my #homelab the last few weeks.

- Replaced the Lenovo Thinkstation E32 node
- 4 #Proxmox servers in cluster
- #ProxmoxBackupServer with qdevice
- Each server having 2x #10Gbit, one being a dedicated SAN network
- Enterprice NVMe for ZFS datastore
- Replaced all fibers in the rack with DACs

I'm seeing high temperatures in both my SFF nodes. Need to figure out a way to push some more air in. No fan headers, so I've ordered some #Noctua S-ATA to 4-pin adapter (NA-SAC5).

After a lot of back and forth; I decided to buy a #MikroTik CRS309-1G-8S+IN and dedicate it to the SAN. I thought a lot about 25 and 100 Gbit, but ultimately decided I'm not ready for the investment. Each server will have 2x #10Gbit, which will just have to do for now 🙂

Ordered lots of things for the #RPiSecuritySystem project:

- Flush mounted buzzer/sounder for the entryway, to replace the homemade one
- More fire alarm stuff; interface card, two more smoke sensors and a laser tester
- Ceiling mounts for the Bosch #PIR sensors, to use in the basement

Here we can see the different stages of the #battery test period, and recharging after.

From the left; the pulse stage, were the voltage varies from 12.7V - 14.4V.

Then we see the test period, where the voltage drops until the battery reaches 50%.

Now charge stages; bulk (ramping up to 14.4V), absorption (keeping 14.4V), analyze (check if dropping below 12V) and float (keep 13.6V). After 10 days of float the pulse stage starts again.

#CTEK has this well documented in their user manuals.

Three voltage levels are measured in the #RaspberryPi alarm system: 5V, 12V auxiliary and the battery voltage.

A drop in the 12V auxiliary is used to detect a mains power failure.

The battery voltage is used to estimate battery level, this is done with a dictionary of voltage to percentage where the missing values are interpolated with scipy.

Once a month a battery test is performed, where the charger is stopped, and the battery voltage monitored until it reaches 50%.

#RPiSecuritySystem

It looks like I've also found the reason why the voltage measurements by the #arduino was so unstable.

Simply a user error — wrong size load capacitor, mounted too far away from the voltage reference. Soldered on a new voltage ref. with load and input capacitors, very close and correct values this time :)

#RPiSecuritySystem

I've spent the last few days working on my #RaspberryPi security system. This house used to have phone outlets here and there, I've repurposed some of those for a hidden buzzer/sounder.

One in the 2nd floor den, and one in the main living room. They can do two sounds; continuous 970 Hz and 800 to 970 Hz sweep 1/s.

Still have the "homemade" buzzer in the entryway. Going to replace that as well :)

#RPiSecuritySystem

It only took me 30 minutes to implement #PageFind, and it produces nice looking results right out of the box. Amazing! https://blog.cavelab.dev/search/

I got a few #Reolink cameras last summer, and made a simple #NVR using a #MediaMTX and #FFmpeg https://blog.cavelab.dev/2024/01/diy-nvr-ffmpeg/