Tag: Gadgets

Unlocking Smartwatches with Unique Heart Rhythms: A Missed Opportunity? | August 06 2025, 16:43

Why has no one made it so that smartwatches only unlock on the wrist of their owner, reading their unique heartbeat or other biometric data? This is in addition to having the owner’s phone nearby.

Officially, you can’t disable this in the settings of an Apple Watch — Apple intentionally made it such that when you put on the watch for the first time each day, it always requires a code, even if the iPhone is nearby. This is due to security policy: the watch may end up on someone else’s wrist, and the phone may just be nearby.

Moreover, every person has unique heart rhythm patterns, which include, for example, slight variations in the intervals between heartbeats, characteristics of the heart signal shape, and how the heart responds to different stresses. These microscopic differences create a unique picture” of heart rhythm that is difficult to fake or replicate. Watches have quite a lot of time, after being worn and before they are needed unlocked, to collect, process, and decide whether to unlock or not.

DIY Wireless Reaction Game: Building Interactive Button-Based Activities | July 28 2025, 22:26

Who knows their way around electronics? Any recommendations?

I want to make a thing some weekend. A big bulbous button. It lights up – you smash it. The app records the time from when it lights up to when it’s smashed. There might be several buttons and they could be scattered – on walls or the floor. WIRELESS. They might light up randomly – this is controlled by the app (phone or computer). Metrics like average reaction time are calculated on the fly for different understandings of the word ‘average’. For instance, you could place buttons on the ground a few meters apart and invent a moving game for the kids. Or attach them to a wall and smash them with a ball. Basically, it’s a technical question.

How would you do it – dumb buttons on an nRF24L01+ chip or smart buttons on an esp32 microcontroller?

In the first case, every such module listens to the radio: as soon as a command with its ID arrives from the central node, it turns on the light. After the button is pressed, it sends back a “pressed” message. The timer is on the side of the central node. Each button has an Arduino Pro Mini + nRF24L01+, but there will also be a central hub with either nRF24L01+ and Arduino Uno, Mega or ESP32, which collects the data and is connected to the computer (Bluetooth or WiFi).

In the second case, the buttons are connected via Bluetooth (BLE) or WiFi. The brains of the button is the ESP32, which needs to be programmed through a programmer.

Cost-wise, both approaches are roughly the same minus the cost of arcade buttons and 3D printing, somewhere around $10-15 per button.

The Art of Lawn Striping: Creating Light and Dark Patterns with Grass | July 14 2025, 14:42

We constantly drive past fields organized into stripes or checks. I finally found the time to look into how this is done. It’s called lawn striping, and the effect is achieved by bending the blades of grass in different directions.

The direction in which the grass bends determines whether a stripe will be light or dark. When the blades lean away from you, the lawn looks lighter because the light reflects off the broad and long surface of the blade. When the blades lean towards you, the lawn appears darker because you are looking at the tips of the blades (smaller reflective surface) and you see shadows under the grass. Therefore, mowing the lawn in opposite directions (up/down, left/right, north/south, east/west, etc.) creates the greatest contrast between the stripes. Interestingly, since the “color” of the stripe depends on the direction from which you look at it, a light stripe will appear dark if viewed from the opposite side.

This fuss over grass is a very American phenomenon. I overcome my laziness to mow the lawn only when the grass has indecently overgrown (the notion of “indecently overgrown” is also something I adjust each year after receiving tsk-tsk letters from the village administration). My neighbor, however, seems to do it every few days, and I once saw him kneeling in the grass—complaining that someone had dragged something across his lot, dropping some chips in the grass and ruining its perfection. Really, the only thing missing was a pair of scissors in his hands.

Persistent Notifications: The AirPods Pro Annoyance on a Flight | June 26 2025, 12:45

This weird thing appears on the phone and you can’t close it, it just keeps popping up again and again, every second. For about five minutes. It’s almost impossible to use the phone. Turns out, there’s a guy sitting one seat away from me on the plane, opening and closing an AirPods case, chatting with a girl. He’s got nothing better to do with his hands, darn it.

Discover Your Flight Gate Early with This Simple Plane Finder Hack | June 24 2025, 22:08

I just found a lifehack on how to determine your departure gate when it’s not yet displayed on the board. Go to planefinder net, enter your flight, and it shows the tail number of the airplane for that specific departure. Click on the link with the tail number, and it shows where the plane is arriving from—the gate it arrives at is known much earlier than the gate from where the new flight departs. So head to this gate, as it’s almost certain to appear on the board by the time someone gets around to updating it.

Yes, everything will go awry if they change the plane. But it’s very unlikely that the airplane will change, as any replacement has to be the same model otherwise it causes chaos with the already assigned seating, and airplanes are not changed often (although it has happened to me several times). Nonetheless, there’s nothing to do at the airport, and playing the game of guessing the gate is interesting.