Teardown on karl

TESmart HKS801-P23-USBK KVM Teardown

Sat, 17 May 2025 00:00:00 +0000

TESmart HKS801-P23-USBK KVM Teardown

Recently, one of the USB ports on my previous KVM switch failed. Since it’s a critical piece of equipment, I needed a replacement the same day. The original AliExpress product page was no longer available; the seller seems to have closed up shop entirely.

Fortunately, the OEM—XUFUNG—has released an updated version, now sold in the US as the TESmart HKS801-P23-USBK. It looks visually identical to the previous KVM switch, but the USB ports now feature the characteristic blue color indicating USB 3.0 support.

Solum 2.2 inch Electronic Shelf Label Teardown

Thu, 20 Jul 2023 00:00:00 +0000

Quick peek inside the EL029F3WRA

In light of the recent news that the OpenEPaperLink firmware has been ported to the nRF52811 series of chips, I decided to take a look inside the Solum EL029F3WRA to see if it was a viable candidate for a project.

As it turns out, it is very similar to the 2.9 inch tags. I hope to soon have a simple CAD model of the ESL which I’ll use to model a basic pogo-pin programming jig for this particular ESL.

Roborock S8 Pro Ultra Teardown

Sat, 06 May 2023 00:00:00 +0000

Roborock S8 teardown

I recently acquired the new S8 from Roborock to replace my rapidly failing roomba.

While I am patiently waiting for Dennis and Hypfer to add Valetudo support, I thought I’d have a peek inside to see if this model will be any more serviceable or maintainable than my current vacuum.

From what I’m told, the S7 and the S8 are supposed to be pretty similar so here’s to hoping that it’s not too much more of a wait.

Teardown and Home Assistant integration with two generic Chinese 'smart' power strips.

Sun, 15 Jan 2023 00:00:00 +0000

I love the Sonoff-S31 smart plugs. They’re cheap, well made and - most importantly - trivial to flash with ESPHome and integrate into Home Assistant. They do have one obvious draw back, though; optimized for a “traditional” US style outlet. When you try to deploy them to a power strip, you end up loosing about 50% of the outlets on the strip!

This is how you loose about 50% of the outlets on your power strip.

Quick look inside two Ali Express mmWave presence detection sensors

Tue, 01 Nov 2022 00:00:00 +0000

Millimeter Wave technology has recently hit “mass consumer product adoption” price points. A casual search for “human presence sensor” on Ali Express will turn up a seemingly endless number of sub $40 devices that can detect movement far more accurately than any old PIR sensor.

Each listing is fairly generic; there’s no explicit manufacturer details but they all use the same marketing images:

As the photos below will show, neither device is super well marked with a model number so I’ll just refer to each by either the color of the enclosure or by the radar sensor inside.

Quick look inside the OMRON Evolv BP7000 Blood Pressure cuff

Sat, 14 May 2022 00:00:00 +0000

A friend recently asked for my help with some reverse engineering. They wanted to know how difficult it would be to re-use some components from a lot of refurbished blood pressure cuffs they had recently acquired.

Sounds easy, right? At a high level, there’s going to be:

a pump and a pressure sensor and a valve
a micro controller to run the show
a way to communicate the readings back to the user

In the interest of expediting things, I asked for the FCC IDs from the devices so I could have a look inside… and was surprized to find out that there was no FCC listing for this particular model from the lot.

Quick look inside Venstar T7850 - One of the only 'no-cloud' WiFi Thermostats that plays nice with Home Assistant

Sat, 23 Apr 2022 00:00:00 +0000

Info

As of 2022-05-11, there is an update on my experience with the thermostat below!

This is another one of those posts from my never ending quest to integrate Home Assistant with All The Things!

The thermostat that was installed when I moved in was an early Nest thermostat. These thermostats are - for the most part - well reviewed and liked. I had no complaints… except one.