A Commmand Center For Children With Sensory Needs

Toys for children are meant to be fun and interactive, but they’re even better if they’re educational as well. For [carrola1], a parent of a 4-year-old suffering from from medical disabilities, sensory needs, and autism, a more personalized approach seemed best. The electrical engineer built a wall-mounted command center with plenty of switches, buttons, and knobs to trigger to keep any child happy.

Apart from basic inputs, the device also has a color sensor – the command center can ask the child for an object of a particular color and congratulate them with a song when they’ve successfully acquired one.

The software for the audio and light controls was written in C for a STM32L0 series MCU, with CMSIS as the hardware abstraction layer and STM32CubeIDE as the IDE. The design uses SPI and I2C for serial communication and I2S for communicating between the digital audio devices. Physical inputs include toggle switches, rotary switches, and key switches to provide variety, with all physical hardware connected to the MCU on a custom PCB.

The audio output, sourced from a library of wav files, seems like the most challenging part of the build: the amps needed to be changed from left channel mono configuration to stereo, the output had to be LC filtered, and the code for had to be optimized for size to allow the audio files to play.

You can check out a video of the command center in action on the Reddit post.


Repurposing A Toy Computer From The 1990s

Our more youthful readers are fairly likely to have owned some incarnation of a VTech educational computer. From the mid-1980s and right up to the present day, VTech has been producing vaguely laptop shaped gadgets aimed at teaching everything from basic reading skills all the way up to world history. Hallmarks of these devices include a miserable monochrome LCD, and unpleasant membrane keyboard, and as [HotKey] found, occasionally a proper Z80 processor.

It started, as such things often do, with eBay. [HotKey] found that the second hand market is flooded with these decades-old educational gadgets, often selling for just a few bucks. As it turns out, children of the smartphone and tablet era don’t seem terribly interested in a “laptop” from 1991. At any rate, he ordered about a dozen different models and started tearing into them to see what made them tick.

He found that the VTech machines of around 20+ years old were using the Z80 processor, and what’s more, they shared a fairly standardized external cartridge interface for adding additional software or saving data. Upon attempting to dump some data from the cartridge port, [HotKey] discovered that it was actually connected to the computer’s main bus. He realized that with a custom designed cartridge, it should be able to take over the system and have it run his own code.

After more than a year of tinkering and talking to other hackers in the Z80 scene, [HotKey] has made some impressive headway. He’s not only created a custom cartridge that lets him load new code and connect to external devices, but he’s also added support for a few VTech machines to z88dk so that others can start writing their own C code for these machines. So far he’s created some very promising proof of concept programs such as a MIDI controller and serial terminal, but ultimately he hopes to create a DOS or CP/M like operating system that will elevate these vintage machines from simple toys to legitimate multi-purpose computers.

We’ve seen VTech hardware hacked in the past, but it’s generally been focused on the company’s more recent hardware such as the Linux-powered InnoTab. It will be interesting to see if these educational toys can fulfill some hacker’s dreams of having a cheap and portable box for Z80 tinkering.

The GENIAC Lives Again

[Mike Gardi] credits his professional successes in the world of software development on the fact that he had access to logic-based educational games of a sort that simply don’t exist anymore. Back in the 1960s, kids who were interested in electronics or the burgeoning world of computers couldn’t just pick up a microcontroller or Raspberry Pi. They had to build their “computers” themselves from a kit.

One of those kits was the GENIus Almost-automatic Computer (GENIAC), a product which today is rare enough to essentially be unobtainable. Using images and documentation he was able to collect online, [Mike] not only managed to create a functioning replica of the GENIAC, but he even took the liberty of fixing some of the issues with the original 60-odd year old design.

Fundamentally, the GENIAC is composed of rotary switches which feed into each other to perform rudimentary logical functions. With banks of incandescent bulbs serving as the output, users could watch how placing the switches in different positions would influence the result.

This might seem a little silly to modern audiences, but thanks to a well written manual that featured a collection of compelling projects, the GENIAC managed to get a lot of mileage out of a couple light bulbs and some wire. In fact, [Mike] says that the GENIAC is often considered one of the first examples of an interactive electronic narrative, as the carefully crafted stories from the manual allowed players to go on virtual adventures long before the average kid had ever heard of a “video game”. A video about how one of these stories, “The Uranium Shipment and the Space Pirates“, can be seen after the break. Even today it would be an interesting enough toy, but back in 1955 it would have been mind-blowing.

Construction of this replica will require access to a laser cutter so you can approximate the original’s drilled Masonite backing and rotors. From there, [Mike] has produced an array of 3D printable components which are attached to the board to serve as contacts, spacers, and various other pieces of bric-a-brac. Some of the parts he couldn’t find pictures of, so he was forced to come up with his own designs. But considering the finicky nature of the original, he thinks his printed parts may actually be better than what the toy shipped with.

If you like his work with GENIAC, be sure to check out the 3D printed replica of “The Amazing Dr. Nim” that [Mike] made last year, or his breathtaking recreation of the Minivac 601.

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