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This is a site for stuff I write that doesn’t fit in 280 characters or simple images.

Blocking spammy caller names with VoIP.ms Call Hunting

I made a small Rust VoIP.ms CNAME blocker.

The short version is that I wanted to block a caller by name instead of by phone number.

This sounds like it should be an option in VoIP.ms. For all the features VoIP.ms has, this is not one of them. So I made one for cheap.

The missing filter

VoIP.ms has a pretty capable CallerID Filtering feature. You can filter on specific caller ID numbers, phone book groups, anonymous callers, calls that do not match the North American number format, STIR/SHAKEN attestation level, and wildcard patterns like area-code-ish blocks.

That is all useful, but these asshole spam callers and scammers do not politely stick to one number. They rotate numbers. Blocking one just means the next call comes from another one. What I wanted to block on was the caller ID name.

VoIP.ms has CNAM support too, but as far as I can tell it is for displaying names, not filtering on them. Their blog post on stopping spam calls talks about filtering numbers, area codes, and anonymous callers, while describing CNAM as a way to identify callers before picking up. The Caller ID wiki page describes incoming Caller ID name lookup as an optional per-DID setting that can display a caller name for US and Canadian callers.

[... 718 words]

7:30 pm / Voip , Sip , Rust , Voip ms , Telephony

Unofficial MakerWorld PMM OpenSCAD Reference

I made an unofficial MakerWorld PMM OpenSCAD reference.

The short version is that I wanted Codex to help me make MakerWorld-customizable OpenSCAD models, and I did not want it guessing from old forum posts, UI behavior, and whatever I happened to remember at 1 AM.

This started because I wanted to use agents on my own OpenSCAD projects without re-teaching the same MakerWorld-specific weirdness every time.

The documentation problem

MakerWorld’s Parametric Model Maker is genuinely useful. OpenSCAD plus a web customizer is a great fit for 3D-printable stuff where the interesting part is “same idea, slightly different dimensions.”

If you have not run into it before, OpenSCAD is CAD by writing code. You write variables, modules, and geometry operations, and it turns that into a model. That makes it very good for customizable prints, and very annoying when a target platform has extra rules.

Unfortunately, the OpenSCAD side of PMM is documented in a very internet way. Some of it is in release posts. Some of it is in support replies. Some of it is in the actual web app. Some of it is people trying things and reporting what happened.

There is a Bambu forum thread literally titled Any Documentation on Parametric Model Maker?. The first post asks where to find the requirements for making customizable models. That felt familiar.

For a human, scattered docs are annoying. For a coding agent, they are a great way to get plausible garbage. It might write OpenSCAD that looks fine locally but misses MakerWorld’s actual rules. It might invent a PMM feature because it saw something sort of similar somewhere else.

I do not want an agent inventing // preview[...] as a PMM feature. I want it to know that // color is a thing, // font is a thing, mw_plate_N() is a thing, and default.svg is not just some random example filename.

So I made a reference.

What I collected

The repo is basically a practical map of the PMM OpenSCAD surface:

  • the PMM OpenSCAD API
  • an agent workflow for converting normal OpenSCAD into PMM-ready OpenSCAD
  • gotchas that agents are likely to mess up
  • compatibility rules
  • public source snapshots
  • patterns and checklists
  • a generated docs site

The small examples are the important ones:

accent = "#FF0000"; // color
font_name = "Roboto"; // font

module mw_plate_1() {
    // printable plate here
}

module mw_assembly_view() {
    // preview-only assembly here
}

svg_file = "default.svg";

None of that is hard once you know it. The problem is making sure the agent knows it before it starts “helping.”

I also made a PMM font index. It has 1881 MakerWorld PMM font families and 8267 exact PMM font strings. This got more elaborate than I expected, but fonts are exactly the kind of thing where an agent can confidently choose something that works on your machine and then does not work where the model actually runs.

Why agent-first

This is not meant to replace the official PMM UI or be a polished tutorial for someone’s first customizable model. It is mostly a pile of receipts and instructions for agents.

Point Codex or another coding agent at the repo, then ask it to adapt a .scad file for MakerWorld. The repo gives it rules to retrieve before it starts editing:

  • flatten local includes when PMM probably will not have them
  • do not remove bundled PMM libraries like BOSL2 just because arbitrary local includes are risky
  • use PMM upload defaults like default.svg and default.stl
  • add // color and // font only where those controls are intended
  • treat multi-plate output as a publishing decision, not just a module name
  • cite whether a claim came from an official app endpoint, official release, employee reply, community report, or inference

That last part matters. I do not want a pile of agent-generated confidence. I want the agent to say why it thinks something is true.

The repo

The project is here:

https://github.com/nelsonjchen/unofficial-makerworld-parametric-model-maker-openscad-docs

The generated docs site is here:

https://nelsonjchen.github.io/unofficial-makerworld-parametric-model-maker-openscad-docs/

This is unofficial, not endorsed by Bambu Lab or MakerWorld, and not a license grant for any font, library, model, or web asset. It is practical documentation from public sources and reverse-engineering.

It is also probably incomplete or wrong in places. PMM keeps changing, and some of this stuff only becomes obvious after someone trips over it.

Anyway, this mostly exists so my agents stop making the same MakerWorld OpenSCAD mistakes. If it saves someone else from digging through forum threads while trying to publish a customizable model, great.

8:15 am / Bambu , Makerworld , Openscad , 3d printing , Codex

Cisco Catalyst 9800-CL on GCP: what a fight

I finally wrote up my notes on getting a modern Cisco Catalyst 9800-CL running on Google Cloud Platform.

The short version is that this was much more of a fight than I expected.

Cisco’s public GCP-facing material still nudges people toward Google Cloud Marketplace, but the Marketplace offerings I found were outrageously old: 16.12.1 and 16.12.2s from the 2019-2020 era, plus 17.2.1 and 17.3.5a from the 2020-2021 era.

That is a pretty bad situation if what you actually want is a modern WLC on GCP. The version I actually worked from was 17.15.04d, which Cisco’s software portal lists with a release date of 19-Dec-2025. Cisco’s public guidance still points at a path that appears stuck on software families from years ago, and it was not a good starting point for getting a current controller running.

The current downloadable image path is possible, but it turned out to involve more image surgery and boot-path archaeology than I had hoped for.

I put the actual handoff-style guide here:

That guide covers:

  • where to get the qcow2
  • why Marketplace is not a great baseline right now
  • what actually worked to get the controller reachable
  • how I validated it was really up
  • how to adopt an AP into the supported public-cloud path

One of the main conclusions is that Cisco’s built-in GCP bootstrap path seems to create real first-boot state that the appliance expects, which helps explain why simply editing /varied/iosxe_config.txt offline was not enough on a pristine raw image.

Anyway: what a fight. But at least the notes are in one place now.

1:15 pm / Cisco , Catalyst 9800 , Gcp , Wireless , Homelab

Bambu Lab Store Filament Tracker

I’ve been running a Bambu Lab Store filament tracker at bbltracker.com.

bbltracker dashboard

I recently got into 3D printing. A lot of what I print is practical: last-millimeter adapters, things like robot vacuum ramps around the house, and other tiny fixes that make daily life less annoying.

Bambu Lab released the P2S, their flagship midrange printer, and I picked one up after hearing how polished their ecosystem is. People call them the Apple of 3D printers, and I can see why. The hardware is solid, but the software and ecosystem are really what make it shine.

There is also a bit of a format war around filament. Bambu sells filament with RFID tags that are not easy for third parties to mimic. The RFID flow makes loading filament easy and automatically applies Bambu-tuned profiles. Some people feel those profiles run too fast, but for my functional prints, they have worked great.

Where the frustration started

I like having color options, and color can be functional too. But stock has been rough for a while, even after the holiday season.

That rough stock situation (and the need for a tracker) is really a symptom of how popular Bambu has gotten, especially over the holidays:

Handy chart showing Bambu popularity spike over the holidays

Source: Reddit comment

Then there is the constant bulk-sale mechanic on the Bambu Lab Store: buy 4+, get a strong discount, buy more, save more. In practice, that falls apart when the combinations you want are never all in stock at the same time.

At the time, the store UI also made this harder than it needed to be. Out-of-stock options were not clearly crossed out, so building a cart felt like guesswork.

That made me angry, but in a constructive way. So I built a tracker.

What the tracker does

At a high level, the tracker monitors store inventory over time, keeps historical snapshots, and renders a dashboard so I can quickly answer:

  • What is actually in stock right now?
  • What appears stable versus constantly draining?
  • What was the last major restock spike?
  • Are there ETA hints for restocks?
  • Is this likely to go out of stock soon?

I started with only the US store, then expanded to EU, CA, UK, AU, and Asia coverage.

I also reused a stock-quantity verification trick I had learned while documenting openpilot’s Toyota security key journey.

Building it fast (and keeping it moving)

I used a lot of Google Antigravity while building this. Web scraping is tedious work, and large language models helped a lot with iteration speed and the constant tweaks.

The codebase is not pretty in every corner, but LLMs have made it very workable to maintain and improve continuously.

Later, I added depletion-rate estimation so the tracker can make a rough guess about when something might go out of stock.

Things that happened after launch

After I released it and posted it on /r/BambuLab, a bunch of interesting things happened:

  • Bambu nerfed the original stock-count hole the tracker used.
  • For a while, counts were capped at 200 in the US view, which reduced visibility.
  • Later, that cap moved to 400 in the US store. Maybe my tracker’s utility was actually a factor in that decision? I do see traffic from China, where there is no Bambu Lab Store of the same codebase as far as I can see.
  • Bambu improved their UI and added clearer out-of-stock cross-outs.
  • I added more quality-of-life indicators, including “stable stock,” ETA context, and restock-spike visibility.
  • I added a GoFundMe and a nice patron funded a custom domain and hosting for the tracker.

Backend at a glance

Keeping this online reliably has mostly been a deployment and operations problem:

If you print a lot and buy filament in batches, this has been much better than manually refreshing product pages and hoping for the best.

8:10 pm / Bambu , Filament , Duckdb , Typescript , Cloud run , Cloudflare pages

Surviving a power outage with fiber ONT and PoE setup (Frontier FOX222)

fox222

power supply

For some reason, it’s been a bit hard to find information on how to setup my particular fiber ONT so that it can survive a power outage with a PoE setup.

While of course, one could power a whole house with solar and batteries, I wanted to find a way to keep my fiber ONT and router powered during a power outage without having to invest in a full home battery system.

Costco recently had on sale a small EcoFlow RIVER 3 Plus Portable Power Station, which I installed into my home network setup with the power station being next to my router.

It’s been wonderful as an UPS!

My setup is a bit peculiar as my Frontier FOX222 ONT is a bit far from the power station, but the power station is next to the router and there is an Ethernet cable running from the ONT to the router. The RIVER 3 is also next to the router.

The only way to provide power to the ONT without also having to plumb AC backed by the power station: A PoE injector on the Ethernet cable between the ONT and the router and a splitter at the ONT end to convert the PoE to 16V DC power for the ONT.

[... 764 words]

6:12 pm / Fiber , Ont , Poe , Setup , Power outage , Frontier , Ecoflow , Ups

Talky Pet Watcher, a cat watching AI

Cat Watch

Github Project: talky_pet_watcher

I’m allergic to cats 😢. But a friend asked me to watch their cat. My family was more than willing to help but to be safe, I wanted to also monitor the cat to make sure she didn’t get into any shenanigans that were too much.

With some cheap TP-Link Tapo cameras, I set up a system to watch the cat remotely and ensure she was safe while I could not be next to her. It’s a Telegram bot that also sends me a message whenever the cat is doing something interesting.

It watches multiple cameras and tries to aggregate the data to provide insights on the cat’s behavior.

Here’s the project description:

Talky Pet Watcher is a tool to watch a series of ONVIF webcams and their streams. It captures video clips, uploads them to Google AI for processing, and uses a generative model to create captions and identify relevant clips. The results are then delivered to a Telegram channel. This project is designed to help pet owners keep an eye on their pets and share interesting moments with friends.

This was slapped together in a few days, as I only watched the cat for two weeks.

I was also interested in Google Gemini and how cheap they claimed to be for analyzing video. I figured that this would be a good way to test it out.

What went well:

  • The system was able to capture interesting moments effectively.
  • It was able to concantate multiple camera’s POV to provide interesting views.
  • The cameras were cheap!
  • Putting the results on Telegram was a good way to share the results with the cat’s owner and friends.

What did not go well (and there are many!):

  • I did not implement history, so the system basically reported the same thing over and over again.
  • Getting reliable clips from multiple cameras when motion was detected was iffy due to the TP-Link Tapo camera’s iffy web servers. It would stall and halt a lot.
  • The Google Gemini AI could only analyze video clips at 1FPS. For an agile kitten, this can sometimes make wrong assumptions about what the cat is doing.
  • Implementation wise, bun was very crashy and I had to restart it a lot.
  • The connection to the camera also had to be restarted a lot.

If I had to do it again:

  • Use something that can pull from a NVR by relative timestamps. There was some Rust NVR but it was too complicated for me to set up in the small amount of time I had.
  • Implement a history system and maybe some memory bank system.
  • And so so much more! 😅

6:08 am / Catte , Google gemini , Vision , Telegram

comma three faux touch keyboard

🦾 comma three Faux-Touch keyboard

Long arms for those of us with short arms from birth or those who can’t afford arm extension surgery!

touchkey keyboard demo

Built a faux-touch keyboard for the comma three using a CH552G microcontroller. The keyboard is off the shelf and reprogrammed to emulat a touchscreen.

It’s a bit of a hack but it certainly beats gorilla arm syndrome while driving.

For $5 of hardware, it’s very hard to beat.

The journey started in January 2024 and ended in May 2024. Though it, I had to struggle with:

  • CH552G programming
  • Linux USB HID Touchscreen protocol
  • Instructions and documentation

It’s also been through that period of unintended usage. The Frogpilot project has had users who were surprisingly interested in using it as an alternative for some GM vehicles where there is no ACC button. They use the keyboard to touch the screen where ACC would be.

Part of the work also meant upstreaming to the the CH552G community. While I doubt it’ll have any users, it’s nice to give back to the community. There is now a touchscreen library for the CH552G.

The project is open source and can be found at:

https://github.com/nelsonjchen/c3-faux-touch-keyboard

There’s a nice readme that explains how to build and flash the firmware.

10:02 pm / Openpilot , Replay , Ch552g , Comma ai , Hardware

Replicate.com openpilot Replay Clipper

Web capture_8-11-2023_9551_replicate com

The replay clipper has been ported to Replicate.com!

https://replicate.com/nelsonjchen/op-replay-clipper

Along with it comes a slew of upgrades and updates:

  • GPU accelerated decoding, rendering, and encoding. NVIDIA GPUs are provided to the Replicate environment and greatly speed up the clipper.
  • Rapid fast downloading of clips. Instead of relying on replay to handle downloads sequentially in a non-parallel manner, we use the parfive library to download underlying data in parallel.
  • Comma Connect URL Input. No need to mentally calculate the starting time and length. Just copy and paste the URL from Comma Connect.
  • Video/UI-less mode. Don’t want UI? You can have it.
  • 360 mode. Render 360 clips
  • Forward Upon Wide. Render clips with the forward clip upon the wide clip
  • Richer error messages to help pinpoint issues.
  • No more having to manage GitHub Codespaces. Replicate handles all the setup and cleanup for you.

Unfortunately, there is a cost. It’s a very small cost but technically Replicate.com is not free. Expect to drop a cent per render. Thankfully, you have a lot a trial credits to burn through and the clipper can run on a free-ish tier.

10:28 pm / Openpilot , Replay , Replicate , Openpilot e2e long , Comma ai

Colorized-Project: A Project-Color restoration.

screenshot_c235a4a9-429b-4564-bfef-24e4f12bd9a8

GitHub Link: https://github.com/nelsonjchen/Colorized-Project

On IntelliJ IDEs, I’ve been using Project-Color to set a color for each project. This is useful for me because I have a lot of projects open at once, and it’s nice to be able to quickly identify which project is which.

Unfortunately, Project-Color hasn’t been updated in a while, and it doesn’t work with the latest versions of IntelliJ.

After a few months of using IntelliJ without Project-Color, I decided to try to fix it. I’ve released the result as Colorized-Project.

Thre are a few rough edges, but it’s mostly functional. I’ve been using it for a few weeks now, and it’s been working well. I’ve also submitted it to the JetBrains plugin repository as well.

It still needs some polish like a nicer icon, and I’d like to add a few more features.

10:28 pm / Intellij , Kotlin

GitHub Wiki SEE: Search Engine Enablement: Year One

It’s been near a year since I supercharged GitHub Wiki SEE with dynamically generating sitemaps.

Since then a few things have changed:

  • GitHub has started to permit a select set of wikis to be indexed.
  • They have not budged on letting un-publically editable wikis be indexed.
  • There is now a star requirement of about 500, and it appears to be steadily decreasing.
  • Many projects have reacted by moving or configuring their wikis to indexable platforms.

As a result, traffic to GitHub Wiki SEE has dropped off dramatically.

stats

This is a good thing, as it means that GitHub is moving in the right direction.

I’m still going to keep the service up, as it’s still useful for wikis that are not yet indexed and there are still about 400,000 wikis that aren’t indexed.

Hopefully GitHub will continue to move in the right direction and allow all wikis to be indexed.

9:04 pm / Github , Wiki , Seo , Flyio

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