I tried finding Hidden Gems on AliExpress AGAIN! (Part 19)

Please never stop this series. This is Awesome.

Not really a hidden gem, but can you try a label printer?

>PicoCalc >look inside >no calculator

12:10 if you put a big magnet below a small magnet you are soldering at let it cool it wont lose any magnetic power

Err, RLCD is just basically going back to non backlit LCDs and calling it fancy "reflective"? :)

i guess most of your audience are not in the EU because no one has mentioned it but FYI: "Starting July 1, 2026, the EU eliminates the €150 duty-free threshold for low-value parcels from AliExpress, introducing a flat €3 customs fee per product category for shipments valued under €150"

I think that RLCD should use way less (RLCDs made by Sharp of similar size/resolution use 15-50uA for static image) and what you've measured is just poor sleep current of ESP32 (which is fair, if you're evaluating whole module).

Thank you for whoever submits those sponsorbolck segments so quick 🙏

I've made my own magnetic connectors. Take a strip of sheet copper or brass, solder a wire to it, then wrap it around a neodymium magnet. This way you don't need to heat up the magnet itself, so it won't lose its magnetism. Plus the copper sheet is what carries the current, so the magnet's resistance is irrelevant. And as the sheet is thin it won't interfere with the magnet's ability to stick to the battery.

A point about the magnet soldering. The curie point for neodymium magnets is a bit over 300C. You'll have to make sure your solder can wet below that point to make sure your magnets do not lose their function.

Dummy cell would be better if it had voltage regulator and thin cable with USB-C connector. ICs are pretty small that it could be placed inside the connector to negotiate highest voltage available, so more power could be delivered without raising current on those thin wires

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while the PicoCalc could definitely serve as a graphing calculator, it is NOT exam compliant in the US. They bar calculators with a QUERTY style keyboard like this has.

Love these Calculators, i had the TI-92 we could make simple programs and graphics ... loved it a lot, was 17 years old ... Regards Jean-François

Real ones will remember that reflective LCDs were extremely common in early PDAs. Some even came with sidelights that still allowed them to be illuminated when required, but provided the best possible viewing under ambient lighting without built-in illumination (at the time).

1:37 because the delivery is too damn expensive here ($77 or R$400 only for the delivery)

rlcd sounds a lot like the old tech we had in the gameboy color

6:53 It states on the specifications that it takes a specific frequency range, AND one specific modulation type(ASK). If the remotes send the signal with another modulation type. Like FSK or PSK. The circuit probably can't read the data. It's a much better choice to examine the signals with a SDR. And it only takes RF remotes. Seems like you are using an IR remote as well?

I used an RLCD for a sailboard instrument, and it performs exceptionally well outdoors, especially in direct sunlight, where it provides much better contrast than a conventional LCD. That's exactly the purpose of this technology, excellent visibility in bright environments. I think many people overlook its main advantages: very low power consumption and outstanding sunlight readability. This makes RLCDs particularly well suited for outdoor portable devices such as bike computers, sailing instruments, and marine electronics, where visibility and battery life often matter more than color reproduction or high refresh rates.

FYI: The WeAct Power Monitor board is sold out and already labeled as "No Longer Sold" for me on AliExpress.