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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?

#361

Post by aetch »

Older 1999-2007 model year Ford vehicles don’t come with an aux input audio option and they have a cd changer under the seat instead. I made an Arduino shield that emulates the CD changer and injects my iPhone’s audio pretending to be a CD. The shield also handles intercepting the car headunit’s playback commands when you press the physical radio buttons on your car so it does a second emulation of a earphone clicker and passes headunit playback commands back to control the phone over the aux cable.

In short I can control my phone’s audio playback using my retro radio headunit using only a wired connection and no Bluetooth.

My schematic and source code are available at https://github.com/ansonl/FordACP-AUX

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

#362

Post by JackMorgan »

I used to listen to lots of mp3s on my computer in the nineties, so I built a USB IR receiver that could interpret signals from a remote control and use it to control winamp.

I made a tool that tracks the current and historical prices of all sailboats in the world to look for possible good deals.

I made a website that let me track my student loan payoff (since I had 30+ different loans) that showed the total payoff as a big red thermometer. I also would track the dates of payments and used that to estimate the total payoff date

I made and open sourced an attendance tracking site for a local school that allows students to come and go throughout the day, but needs to ensure they at least showed up and returned before school let out.

I made a tool that would determine the most efficient way to build damage per second on each hero in a moba. It used linear optimization to calculate which items to build and in what order to get the highest DPS.

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

#363

Post by polygamous_bat »

mvcalder wrote: post #334

I trained the raccoons that visit my house at night. I started them out getting a peanuts from a water bottle. Then I tied the bottle to a rope. Then kept raising the bottle higher. At that point, I built an automated feeder system using a linear actuator activated by pulling the rope with the bottle attached. It had LEDs that were green / red to show when the feeder would / wouldn't dispense peanuts. It was all driv…

Now teach them how to do simple taxes and you'll have an army of ghost CPAs that can do a similar amount of good to Batman with much less violence.

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

#364

Post by arbuge »

I built this about 4 years ago... I have about half a dozen of them around the house right now showing stock quotes, weather, etc. and updating every 5 minutes.

https://foundrytechnologies.com/relay.php

One of them has been outside the front door showing messages to visitors and exposed to the Texas elements for all that time now - still going strong. About 2 years ago I replaced the plastic case, which was looking a bit warped.

Sold a few too - though not enough to scale things up. Hardware is hard.

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

#365

Post by shanebellone »

I believe tech has passed down inefficient solutions that represented the best solution given the hardware constraints of the time. For this reason, I began rebuilding my web stack.

Deployed applications:

Analytics, Object Database, and WAF.

Deploying shortly:

WSGI app and templating system.

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

#366

Post by giuliogabrieli »

I built myself a phototrap using a Raspberry Pi and a spare webcam. It was a proof of concept to demonstrate a function of a python package I developed for aesthetic analysis of images, that was presented at an international conference. The camera detects movements, and send an image to my via Telegram. I am now using it to take pictures of stray cats moving outside my house.

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

#367

Post by chrbr »

When I was house-hunting I ended up writing a console app for my wife and I to do a few things:

- Pulled down applicable YNAB savings envelope balances and future income calculations from a Google Sheets spreadsheet (which included stock prices for determining RSU payouts) to know how much cash we'd have for down payments at any time in the next 12 months

- Allowed us to either give a house price and have it output when we could afford it, or give a month and tell us how much we could afford if we bought on that month

- Do budgetary analysis of what the monthly payment would be, given fluctuating mortgage rates and estimated insurance from scraping Zillow/Redfin

- Calculated transit times to my office and my wife's office using Google Maps

- Allowed for swappable "scenarios" for all the above to show what would happen if we wanted to sell our current place first and then buy, buy and then sell, or buy-renovate-sell, so we could evaluate all options. We ended up going the buy-renovate-sell path in reality, and it was a huge stress relief to have hard numbers showing us the money was going to be fine.

- Output several months of cash reserves for each scenario after all transactions were done, so we could know if we would cut too much into savings

- Output a yes/no decision based on all of the above to keep us grounded and help prevent over-reaching for a house we couldn't afford - basically enforcing rules on ourselves

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

#368

Post by spyremeown »

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 awesome. Really nice!

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

#369

Post by jim_lawless »

I wrote a set of Python/PIL scripts to arrange image collages for print calendars, web backgrounds, ...etc. In one particular script I use to build backgrounds, the images remain the same height but they can be different widths. The images built are seamless. Here's an example of some comic book covers in a collage using one of these scripts:

https://jiml.us/bp/

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

#370

Post by StuGoss »

I like to fish at night. So I built 3D printed bobbers with an LED diode and scavenged LiPo batteries from vapes inside. It has a dime sized wireless charger receiving coil that is glued inside to a slightly flattened bottom. Externally I built a mini solar panel that charges a scavenged 18650 that charges the battery with a wireless transmitter. The bobber is about the size of a golf ball. I used a slow blinking LED diode that changes color of the bobber. Haven't caught a fish with it yet but it is mesmerizing watching it change colors and bob on the water.
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