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Ask HN: Most interesting tech you built for just yourself?

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Re: Ask HN: Most interesting tech you built for just yourself?

#431

Post by nXqd »

sriram_malhar wrote: post #149

My MIL is 93, and the only tech she can really deal with is turning on the radio and TV and changing channels. She is fond of music from old classics (from the 60's and earlier), so I hooked up a Raspberry PI with an FM transmitter and created her own private radio station. She tells me what songs she likes and I create different playlists that get broadcast on her station. It preserves the surprise element of radio,…

wow, I really enjoy the idea that basically, she just uses what works for her with better content. Really nice work

Re: Ask HN: Most interesting tech you built for just yourself?

#433

Post by nXqd »

jo-m wrote: post #254

I have a rail line right under my apartment, so I built a small computer vision app running on a Rasperry Pi which records each train passing, and tries to stitch an image of it. It has a frontend at https://trains.jo-m.ch/ . Edit: it's currently raining and the rain drops are disturbing the images a bit.

this is so cool :D

Re: Ask HN: Most interesting tech you built for just yourself?

#434

Post by tiborsaas »

During the lockdown me and my girlfriend to watch movies remotely synced, I wrote a service to sync VNC instances together via websocket. It worked via the web control panel of VLC and a Chrome extension was handling the websocket messages and clicking on the buttons. It even added some indicators to show if we both connected.

Re: Ask HN: Most interesting tech you built for just yourself?

#435

Post by michaeltbuss »

Every night, at 3 AM, my cat will meow and paw at the bedroom door like a banshee. I tried everything to get him to stop, including the off-the-shelf air sprayers that trigger with motion.

Eventually, I decided to build my own. I 3D printed a case and trigger for an air sprayer can, created some electronics with an ESP32 and RF trigger, and wrote my own "motion detection" logic - this time with an ultrasonic sensor, which works much better in the dark.

Now, the cat knows that a meow or paw will get him sprayed, and my wife and I can finally sleep!

I also built an air filtration system for my 3D printer, a level checker for my water softener, and a custom keepsake box that only opens with an RFID chip that you can read more about on my blog: https://www.mikebuss.com/blog

Re: Ask HN: Most interesting tech you built for just yourself?

#436

Post by JKCalhoun »

michaeltbuss wrote: post #435

Every night, at 3 AM, my cat will meow and paw at the bedroom door like a banshee. I tried everything to get him to stop, including the off-the-shelf air sprayers that trigger with motion. Eventually, I decided to build my own. I 3D printed a case and trigger for an air sprayer can, created some electronics with an ESP32 and RF trigger, and wrote my own "motion detection" logic - this time with an ultrasonic sensor,…

We need this.

Re: Ask HN: Most interesting tech you built for just yourself?

#437

Post by ludee0 »

After years of trying I've finally made something that my girlfriend would use without me nagging her to try. A small sveltekit app that registers our expenses and tracks who owns who, basically splitwise with way less features, but way more control over my data. I'm really happy every time I see her note down the expense into the app.

Re: Ask HN: Most interesting tech you built for just yourself?

#438

Post by turshija »

About 10 years ago when Droplr deprecated their free packages (and went to paid only) I've made my own free alternative - https://pics.rs followed with its own screenshot app for Windows (C#) and later Mac (Electron) and still use it daily... I needed a screenshot tool which allows me to select a part of the screen, uploads it and immediately copies URL to clipboard. Now I'm finding myself using it without app by doing CMD + CTRL + SHIFT + 4 which copies image directly in clipboard and then opening pics.rs and pressing CMD + V (paste event triggers upload if it contains image in clipboard)

I haven't touched the UI since then, its ugly but it works, I've tried allocating time to make more modern version and even started refactoring it a few times with a few friends in our spare time, but unfortunately finding time next to full-time jobs and family is much harder than it was 10+ years ago :)

I've never advertised it anywhere except shared with friends and used it on some forums in the past, but it slowly grew to 10k registered members and almost 200k uploaded pictures. At this scale (~100GB of data) its very cheap to keep it online since its using very small amount of resources on dedicated servers where I host some other important apps with regular off-site backups, but if it ever spikes and becomes problematic financially it will at least give me more motivation to make something more serious out of it or just slam ads onto it and call it a day (worst case scenario, not a fan of it).

Re: Ask HN: Most interesting tech you built for just yourself?

#439

Post by TrueDuality »

It's not personally useful but I wanted to see if I could design and build a navigation controller designed for a satellite with different configurations. I started with a sandbox simulator that emulated all the hardware sensors down to the noise (according to their data sheets) and a microcontroller emulator that ran real code compiled for a microcontroller I chose for the task (STM32G431).

I tested different control schemes and thrust firing plans, added support for different types of thrusters, errors in sensor readings, atmospheric drag depending on altitude, weird anomalies in the earth's magnetic field, simulated bit flip events and hardware lockups (I left the internal watchdog out of the hardware lockups which is probably not realistic).

In an effort to stress test my simulator I ended up writing a genetic algorithm solver for thruster, magneto-torquer, and reaction wheel placement on arbitrary craft bodies with different mission plans and let it solve it.

I ended up designing a physical circuit board matching the simulator, flashing the board with the same code that was running in the simulator and it worked! I roughly made an approximate cube sat (10cm^3) (had a mechanical engineer friend design me a frame and manufacture it for me) with some small cold gas thrusters out of pressurized CO2 cartridges, controlled by solenoids, and placed by my genetic algorithm.

I dropped it off a cliff that was ~600ft high (best I could do for a "zero gravity" environment that was away from people). It was able to completely arrest its angular rotation before slamming into the ground which is better than I was expecting.

Re: Ask HN: Most interesting tech you built for just yourself?

#440

Post by pwpw »

JKCalhoun wrote: post #386

I have a "TV channel" app running on a Raspberry Pi serving up local video content to a schedule I create. The Pi has a 5TB hard drive attached with perhaps 1000 videos or so. The app has a schedule and plays the videos according to the schedule. It starts up in the morning, plays tele-courses, moves on to old TV shows, an afternoon movie, after school shows begin around 3:00 PM, a comedy show around dinner time, an…

I have been thinking about doing exactly this for Saturday morning cartoons to stream anime to my PVM once I can figure out how to stream 480i from a modern device to RGB.

Would consider sharing how you set it up? I’d love to do something similar!

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