10 | November | 2022

We take shortcuts all the time with our physical models. We rarely consider that the wire has resistance, for example, or that batteries have a source impedance. It’s fine until the point it’s not. Take the case of the Navy’s Grumman F11F Tiger aircraft. The supersonic aircraft was impressive, although it suffered from some fatal flaws. But it also has the distinction of being the first plane to ever shoot itself down.

So here’s the simple math. An airplane traveling Mach 1 is moving around 1,200 km/h — the exact number depends on a few things like your altitude and the humidity. Let’s say about 333 m/s. Bullets from a 20 mm gun, on the other hand, travel at more than 1000 m/second. So when the bullet leaves the plane it will take the plane over three seconds to reach it, and by then it’s moved further and further away, right?

Continue reading “The Importance of Physical Models: How Not to Shoot Yourself in the Foot or Elsewhere” →

[Hack Club] is a group that aims to teach teenagers about technology by involving them in open source projects. One of the group’s latest efforts is Sprig, an open source handheld game console, and [Hack Club] have even given them away!

The console is based on a Raspberry Pi Pico, paired with a TFT7735 display. There is also a MAX98357A audio amplifier on board to provide audio. Other than that, there are ten buttons for control, some LEDs for feedback, and it’s all assembled on a custom PCB designed for easy soldering.

A lot of work has gone into making Sprig an accessible platform for first-time developers. Games can be created for Sprig and run either on the device or in an online editor. [Hack Club] is even running a program that will give away Sprig hardware to kids and teens around the world who write a game for the platform and submit it to the online gallery.

If you’re eager to get into game development while understanding both the hardware and software sides of things, Sprig might be just what you’re looking for. Since today’s microcontrollers are so cheap and so powerful, we’ve seen some other great handheld designs recently too!

Halloween may be behind us, but we couldn’t resist showing you [Mellow]his latest project: an automatic candy dispenser that takes the hard work out of serving trick-or-treaters. It’s a cool build that can serve as inspiration for next year’s Halloween project, or perhaps for a completely different occasion: think birthday parties or Valentine’s Day. After all, when is a bad time to give sweet treats to someone you love?

The basic concept is a scary face, made of wood, that sucks a certain amount of candy through its mouth after you press its nose. The dispensing mechanism is made from 3D printed mechanical parts as well as a piece of drain pipe. Candy is stored in the tube, with a servo-operated flap that releases a set amount each time the nose is pressed. [Mellow] cleverly designed the flap to be somewhat flexible so that it wouldn’t crush any candy bars that got stuck between it and the tube.

A Wemos D1 Mini reads out the nose switch and drives the candy-dispensing servo, as well as two additional servos that turn the eyes left and right for added visual effect. The original idea was to have the eyes swinging all the time, but because the mechanism turned out to be quite tall [Mellow] changed the code to only move them during the candy dispensing process.

We’ve seen several designs for automated candy dispensers over the years, ranging from a Jack-o-Lantern that holds enough candy to feed a small town, to a beautifully over-engineered machine more suitable as a Valentine’s Day gift.

Continue reading “Automatic Candy Dispenser Takes the Hard Work Out of Halloween” →