Ulvain
@Ulvain@sh.itjust.works
- Comment on US Border Patrol detained a nursing mother and separated her from her infant daughter to the point that she needed medical attention as a result of not being able to nurse 3 days ago:
Why?
“If you don’t look Aryan, we want you to feel like this is not a country you’re welcome in. Get out.” Is the message they’re passing, with illegal cruelty as the medium.
- Comment on Tumult in U.S. Treasurys shows Trump's 'big, beautiful bill' might be disaster 3 days ago:
All I’m gonna say is that this image of Trump seems to be begging to be defaced. Nuff said.
- Comment on Parasitology 1 week ago:
Wasn’t there a whole weird theory that toxoplasmosis was also driving a bunch of human behaviour?
- Comment on I wonder what the specs are on the technology that disables shopping cart wheels 4 weeks ago:
This might actually be a good opportunity for an AI answer:
–
First, understand the basic principle you’re working with:
Shopping cart wheel locks respond to a specific RF (radio frequency) signal (typically around 7.8 kHz to 10 kHz for many systems, but it varies by brand).
In normal operation, the boundary wire emits this signal constantly.
The unlocking posts emit a different coded signal to reset the wheel.
So to design a portable device that could lock and unlock wheels manually anywhere, you would need:
- Identify the Signals
You must figure out the exact frequencies and modulation patterns used by the cart system.
Different companies (like Gatekeeper Systems, Carttronics, etc.) use slightly different RF signatures.
Usually lock signal = basic broadcast (constant tone) Unlock signal = special modulated unlock code or sequence.
This might require:
A spectrum analyzer
Or reverse-engineering an existing unlock station.
- Design the Portable Emitter
The portable device needs:
A programmable low-frequency RF transmitter (around 8–10 kHz range, low power)
A microcontroller (Arduino, ESP32, etc.) to generate the right modulation if the signal is coded
An amplifier to make the signal strong enough to reach the cart wheels (they usually detect it within 3–10 feet)
Optionally:
Two modes: a “lock” mode (sending the boundary signal) and an “unlock” mode (sending the unlock code).
- Basic Hardware Components
Low-frequency oscillator (to generate 7.8–10 kHz wave)
Microcontroller (to handle switching, coding)
Coil antenna (for strong near-field transmission — like a small induction coil)
Amplifier circuit (boost the signal so carts sense it a few meters away)
Battery pack (portable, rechargeable — say 12V lithium-ion)
Mode selector switch (Lock / Unlock)
- Software
Simple microcontroller code to:
Emit plain carrier signal = Lock mode
Emit modulated code = Unlock mode
Example (pseudo-Arduino code):
if (mode == LOCK) { generateContinuousTone(8kHz); } else if (mode == UNLOCK) { generateUnlockCode(); }
- Important Challenges
Matching signal format exactly: If the unlock signal is digitally modulated (like FSK or ASK), you must match the timing perfectly.
Power levels: Too much power could fry circuits or interfere with nearby electronics. Keeping it safe is key.
Legal considerations: Broadcasting radio signals, even low-power ones, can be restricted depending on the country.
Simple Concept Sketch:
[Portable RF Cart Lock/Unlock Device]
Size: About a large walkie-talkie
Two buttons: Lock / Unlock
Coil antenna: About 3–6 inches
Range: 1–3 meters effective
Display: Small LED indicators (Locking / Unlocking / Signal OK)
In short: You’re essentially building a portable invisible “fence” generator with two channels: a “keep away” signal (lock) and a “come back” signal (unlock).
- Comment on Bad UX is keeping the majority of people away from Lemmy 3 months ago:
Thanks for sharing! Very much aligned with what i have in mind… Only difference would be to narrow down to 1 or 2 (if at all) on the landing screen - maybe all other options are under a “advanced user? Click here to expand server selection” or something like that…
- Comment on Bad UX is keeping the majority of people away from Lemmy 3 months ago:
Couldn’t we design an “onboarder” where when you get started on lemmy, a “let’s get you started” wizard asks you 2 or 3 questions and based on your answers, it proposes 2 or 3 servers (or directly assigns you to one)?
- Comment on Also available in chocolate. 3 months ago:
The company never took off… Never could get over the hump.
- Comment on Enshrouded's "largest update so far" is out with a new mountain region, pets and single-player pausing 6 months ago:
Been playing for the last month - it’s an awesome game, how come it wasn’t lauded with fanfare and trumpets by the community?!
- Comment on Subnautica 2 is coming in 2025 with four player co-op - here's the announcement trailer 7 months ago:
I hope they inspired themselves from how Grounded integrated multiplayer, sandbox world building and storytelling together
- Comment on Trying to earn a record for "youngest person to <insert a thing>" is just an IRL speedrun 7 months ago:
Incidentally, “youngest person to insert a thing” is a slippery slope and a great way to end up on a list. Shit.