Day: November 4, 2024

Reusing An Old Android Phone For GPIO With External USB Devices

November 4, 2024 by 29 Comments

Each year millions of old smartphones are either tossed as e-waste or are condemned to lie unloved in dusty drawers, despite the hardware in them usually being still perfectly fine. Reusing these little computers for another purpose once the phone’s manufacturer drops support is made hard by a range of hardware and software (driver) issues. One possible way to do so is suggested by [Doctor Volt] in a video where a Samsung Galaxy S4 is combined with a USB-connected FT232R board to add external GPIO.

The idea is pretty simple: the serial adapter is recognized by the existing Android OS and within the standard Android development environment this module can be used. Within this demonstrator it’s merely used to blink some LEDs and react to inputs, but it shows how to reuse one of these phones in a non-destructive manner. Even better is that the phone’s existing sensors and cameras can still be used as normal in this way, too, which opens a whole range of (cheap) DIY projects that can be programmed either in Java/Kotlin or in C or C++ via the Native Development Kit.

The only wrinkle is that while the phone is connected like this, charging is not possible. For the S4 it’s easy to solve as it has a removable battery, so an external power input was wired in with a dummy battery-sized bit of perfboard. With modern phones without removable batteries simultaneous USB/audio dongle and charging usage via the USB-C connector is claimed to be possible, but this is something to check beforehand.

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Three 3D printed, spring loaded contraptions sit on a wooden shield. There are arrow shafts connected to the end and a piece of monofilament fishing line extending away from them and through a small eyelet at the edge of. the shield.

How To Shoot Actors With Arrows Sans CGI

November 4, 2024 by 13 Comments

Today, movie effects are mostly done in CGI, especially if they’re of the death-defying type. [Tyler Bell] shows us how they shot actors with arrows before CGI.

Almost every medieval movie has someone getting shot with an arrow, but how do you do that non-destructively? [Bell] shows us two primary methods that were used, the pop up rig and steel pronged arrows. The pop up rig is a spring loaded device with one end of an arrow attached that pops up when a mechanism is triggered. [Bell] 3D printed his own version of the mechanism and shows us how it can be used to great effect on shots from the side or rear of the victim.

But what about straight on shots where the rig would be blatantly obvious? That’s when you get to actually shoot the actor (or their stunt double anyway). To do this safely, actors would wear wooden body armor under their costumes and arrows with two small prongs would be shot along a wire into the desired impact site. We appreciate [Bell] using a mannequin for testing before letting his brother shoot him with an arrow. That’s definitely the next level above a trust fall.

We even get a look at using air cannons to launch arrow storms at the end which is particularly epic. Looking for more movie magic? How about the effects from King Kong or Flight of the Navigator?

Thanks to [Xerxes3rd] on Discord for the tip!

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