Year: 2020

Solid State Relay Simulation, Explained

February 19, 2020 by 16 Comments

[SaltyPuglord] needed a solid state relay for a project. We’d have just bought one, but he decided to design his own in LTSpice. Along the way he made the video below, which is pretty informative and a good example of a non-trivial design in LTSpice.

MOSFETs have made designs like this a lot easier, to the extent that it should be as easy as putting a pair of beefy fets in-line with the AC source and load. However, that has a few ramifications that [Salty] covers in the video.

The biggest concern comes in isolating the DC supply from ground. He used a transformer which is tricky to simulate in LTSpice. Beyond that the design of the power supply is quite simple, and as he mentions in the video, you don’t really need this complex of a regulator just to feed the gates of the MOSFETs.

Continue reading “Solid State Relay Simulation, Explained” →

The CarolinaCon 16 Badge Slithers Into Life

February 19, 2020 by 2 Comments

It’s something of an unwritten rule at this point that you can’t hold a hacking conference without providing a badge with at least a few LEDs on it. Not only can they be a great way to learn electronics for the attendees that tinker with them, but they’re a keepsake to commemorate the event. As a perfect example, [Matt Agius] recently wrote in to tell us about the badge he’s made for the upcoming CarolinaCon 16.

As [Matt] explains, the idea with this badge was to make it as easy as possible for attendees to assemble. In the final version there are only going to be three components that need to be soldered, so even if they’ve never touched SMD components before, they should still be able to get their badge lit up.

The badge largely makes up for its simplistic electronics with some fantastic board art on the flip side. The two red LEDs illuminate the eyes of a rather sinister looking octopus that’s ensnaring the unsuspecting state of North Carolina in its tentacled grip. The art was originally done by [Katie Dorn], with [Matt] spearheading its conversion into something that could be sent out for PCB fabrication.

Anyone looking to add this latest entry to their growing collection of badges will need to attend CarolinaCon on April 10th and 11th, where you’ll be able to catch a talk [Matt] is giving on the subject called “How to design Printed Circuit Boards for Hacking and for Art”.

Lil’ ESP32 Bot Does Remote Surveillance, And It’s Easy

February 19, 2020 by 7 Comments

Digital cameras have been around for a long time, as have small remote control robotics platforms. However, combining the two has really only come into its own in the last decade or so, as more bandwidth has become available to the home tinkerer. This ESP32-CAM surveillance bot is a great example of what was once hard becoming trivially easy.

It’s a case of standing on the shoulders of giants. The ESP32-CAM is a device that allows one to stream live video images over a network using existing example code. In this case, it’s combined with an L298N DC motor driver which allows the Adafruit robot platform to be steered like a tank via its two wheels. A pair of SG90 servos then serve as a pan/tilt mechanism to further improve the robot’s field of view.

If you aimed to attempt this back in 2010, you’d have spent six months figuring out how to get a microcontroller to talk to a small camera module. Only then could you consider solving the multitude of other problems presented by getting the video feed off the bot to somewhere useful. These days, you can order a bunch of parts online and have it up and running in a couple hours. This project from 2013 serves as an example of how much things have changed in the intervening years. Video after the break.

Continue reading “Lil’ ESP32 Bot Does Remote Surveillance, And It’s Easy” →

Machine Inside Of A Chip: How Sprite_TM Built The FPGA Game Boy Badge

February 19, 2020 by 12 Comments

Kids of the 1990’s would call you a liar if you told them that within thirty years you’d go to a conference and be handed a Super Nintendo Entertainment System to wear around your neck. But that’s what happened with the badge Jeroen Domburg, aka [Sprite_TM], designed for the 2019 Hackaday Superconference. It’s built in the Game Boy form factor, complete with a cartridge slot, beautiful screen, and the familiar button layout. But there’s so much more here, like the HDMI port on the bottom and the ability to completely reconfigure the device by dropping a binary file onto it over USB.

Of course what makes this possible is the FPGA at the heart of the design. The story of how the badge was developed is shared in great detail during Sprite’s Supercon talk. The timeline, the hardware choices, and the oopses along the way make for a great story. But what you really don’t want to miss is how he built the machine inside of the FPGA — the collection of Verilog code known as “gateware” that brings together the System-on-a-Chip (SoC). From his delight at being able to spawn more processor cores by changing a single variable, to the fascinating SNES-inspired graphics subsystem, the inside story shared below is even more interesting than the physical device itself.

Continue reading “Machine Inside Of A Chip: How Sprite_TM Built The FPGA Game Boy Badge” →

Inputs Of Interest: Ears To Communication For Everyone

February 19, 2020 by 20 Comments

Welcome back to Inputs of Interest! If you haven’t heard, I am all ears when it comes to new ways of talking to computers and machines. And speaking of ears, did you know they can do useful tricks? If you squeeze your eyes shut tightly and/or yawn widely, you might hear a low-level rumbling sound like distant thunder. A decent percentage of people are able to move theirs voluntarily, but not everyone. Maybe you already knew you could rumble, and have used it to entertain yourself, or dampen the unpleasant sounds of life.

No, you can’t reach your tensor tympani with a Q-tip. Image via Research Gate

That rumbling is caused by a muscle in your middle ear stretching out. It’s called the tensor tympani, and its purpose is to shield your ears from loud sounds like chewing, and oddly enough, thunder. When the tensor tympani are activated, they pull the eardrums taut to keep them from vibrating and getting damaged. Unfortunately, they don’t react quickly enough to protect us from sudden sounds like gunshots.

Nick G is able to rumble on command, and wanted to see if he could somehow use it as an input mechanism that he calls Earswitch. He got a cheap USB otoscope camera and figured out that the tensor tympani’s stretching movement shows up well enough to trigger motion detection software. So far, [Nick] has been able to demonstrate control of a few things, like the Windows on-screen keyboard, Grid3 assistive software, and a head tracking utility.

Continue reading “Inputs Of Interest: Ears To Communication For Everyone” →

3D Print Your 3D Scanner

February 19, 2020 by 15 Comments

[QLRO] wanted a 3D scanner, but didn’t like any of the existing designs. Some were too complex. Some were simple but required you to do things by hand. That led to him designing his own that he calls AAScan. You can see the thing operating in the video below.

In general, you can move the camera around the object or you can move the object around while the camera stays fixed. This design chooses the latter. You’ll need a stepper motor with a driver board and an Arduino to make the turntable rotate. You also need a computer running Python and Meshroom. The phone also has to run Python and [QLRO] used QPython on an Android device.

Continue reading “3D Print Your 3D Scanner” →

MakerBot Targets Schools With Rebranded Printers

February 19, 2020 by 34 Comments

MakerBot was poised to be one of the greatest success stories of the open source hardware movement. Founded on the shared knowledge of the RepRap community, they created the first practical desktop 3D printer aimed at consumers over a decade ago. But today, after being bought out by Stratasys and abandoning their open source roots, the company is all but completely absent in the market they helped to create. Cheaper and better printers, some of which built on that same RepRap lineage, have completely taken over in the consumer space; forcing MakerBot to refocus their efforts on professional and educational customers.

This fundamental restructuring of the company is perhaps nowhere more evident than in the recent unveiling of “SKETCH Classroom”: an $1,800 package that includes lesson plans, a teacher certification program, several rolls of filament, and two of the company’s new SKETCH printers. It even includes access to MakerBot Cloud, a new online service that aims to help teachers juggle student’s print jobs between multiple SKETCH printers.

Of course, the biggest takeaway from this announcement for the average Hackaday reader is that MakerBot is releasing new hardware. Their last printer was clearly not designed (or priced) for makers, and even a current-generation Replicator costs more than the entire SKETCH Classroom package. On the surface, it might seem like this is a return to a more reasonable pricing model for MakeBot’s products; something that could even help them regain some of the market share they’ve lost over the years.

There’s only one problem, MakerBot didn’t actually make the SKETCH. This once industry-leading company has now come full-circle, and is using a rebranded printer as the keystone of their push into the educational market. Whether they were unable to build a printer cheap enough to appeal to schools or simply didn’t want to, the message is clear: if you can’t beat them, join them.

Continue reading “MakerBot Targets Schools With Rebranded Printers” →