Teardown: VTech Smart Start

Regular readers may be aware that I have a certain affinity for vintage VTech educational toys, especially ones that attempted to visually or even functionally tie in with contemporary computer design. In the late 1980s, when it became obvious the personal computer was here to stay, these devices were seen as an affordable way to give kids and even young teens hands-on time with something that at least somewhat resembled the far more expensive machines their parents were using.

Much Smarter: VTech PreComputer 1000

A perfect example is the PreComputer 1000, released in 1988. Featuring a full QWERTY keyboard and the ability to run BASIC programs, it truly blurred the line between toy and computer. In fact from a technical standpoint it wasn’t far removed from early desktop computers, as it was powered by the same Zilog Z80 CPU found in the TRS-80 Model I.

By comparison, the Smart Start has more in common with a desktop electronic calculator. Even though it was released just two years prior to the PreComputer 1000, you can tell at a glance that it’s a far more simplistic device. That’s due at least in part to the fact that it was aimed at a younger audience, but surely the rapid advancement of computer technology at the time also played a part. Somewhat ironically, VTech did still at least attempt to make the Smart Start look like a desktop computer, complete with the faux disk drive on the front panel.

Of course, looks can be deceiving. While the Smart Start looks decidedly juvenile on the outside, that doesn’t mean there aren’t a few surprising technical discoveries lurking under its beige plastic exterior. There’s only one way to find out.

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RGB LED Shutter Shades

[splat238] is back at it again with another cool RGB LED display project. We were contemplating whether or not our readers have had enough of these over the last few weeks, but we’ve learned over the years that you can never have too many LED projects.

Instead of making a cool mask like we’ve covered before, [splat238] decided to trick-out some shutter shades. What’s really cool is he used the PCB itself as the frame, similar to another hack we’ve seen, which we’re sure also made his design process that much more convenient.

[splat238] got his boards pre-assembled since it would be really difficult to solder all those LEDs by hand. There are 76 of them in this design. It’s pretty helpful that he walks the reader through how to get the boards assembled, providing information on reliable fabrication and assembly houses that he’s had good experiences with. Pretty solid information if you don’t already have a go-to one-stop-house or have never designed for assembly before.

The glasses use an ESP8266-based microcontroller since it has plenty of space for storing LED patterns and has the potential benefit of including WiFi control in later revisions. However, we think you’ll be pretty happy with simply toggling through the patterns with a simple pushbutton.

The LEDs use a whopping 2.5 A at maximum and rely on an external power bank, so you’ll probably want to be really careful wearing this over an extended period of time. Maybe consider doing a bit of PWM to help reduce power consumption.

Another cool project [splat238]! Keep them coming. Continue reading “RGB LED Shutter Shades”

A Face Mask That’s Functional And Hacker-Certified

[splat238] needed a mask for going out in public, but wanted something that fit his personal style a bit better than the cloth masks everyone else was wearing. So, he upcycled his old airsoft mesh mask using an impressive 104 NeoPixels to create his NeoPixel LED Face Mask.

The NeoPixels are based on the popular WS2812b LEDs. These are individually addressable RGB LEDs with a pretty impressive glow. [splat238] purchased a 144 NeoPixel strip to avoid having to solder each of those 104 NeoPixels one-by-one. He cut the 144-LED strip into smaller segments to help fit the LEDs around the mask. He then soldered the power and data lines together so that he could still control the LEDs as if they were one strip and not the several segments he cut them into. He needed a pretty bulky battery pack to power the whole thing. You can imagine how much power 104 RGB LEDs would need to run. We recommend adding a battery protection circuit next time as these LEDs probably draw a hefty amount of current.

He designed his own controller board featuring an ESP8266 microcontroller. Given its sizable internal memory, the ESP8266 makes it easy to store a variety of LED patterns without worrying about running out of programming space. He’s also hoping to add some WiFi features in later revisions of his mask, so the ESP8266 is a no-brainer. Additionally, his controller board features three pushbuttons that allow him to toggle through different LED patterns on the fly.

Cool project [splat238]! Looking forward to the WiFi version.

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Teardown: Cobra XRS 9740 Radar Detector

Drivers with a lead foot more often than not have Waze open on their phone so they can see if other drivers have spotted cops up ahead. But avoiding a speeding ticket used to involve a lot more hardware than software. Back before the smartphone revolution, that same driver would have had a radar detector on their dashboard. That’s not to say the gadgets are completely unused today, but between their relatively high cost (one of the top rated models on Amazon as of this writing costs over $300) and the inevitable false positives from so many vehicles on the road having their own radar and LIDAR systems, they’ve certainly become a less common sight over the years

The subject of today’s teardown is a perfect example of “Peak Radar Detector”. Manufactured back in 2007, the Cobra XRS 9740 would have been a fairly mid-range entry offering the sort of features that would have been desirable at the time. Over a decade ago, having an alphanumeric display, voice alerts, and a digital compass were all things worth shouting about on the box the thing was sold in. Though looking like some kind of Cardassian warship was apparently just an added bonus.

As the name implies these devices are primarily for detecting radar activity, but by this point they’d also been expanded to pick up infrared lasers and the strobe beacons on emergency vehicles. But false positives were always a problem, so the device allows the user to select which signals it should be on the lookout for. If you were getting some kind of interference that convinced the detector it was being bombarded with IR lasers, you could just turn that function off without having to pull the plug entirely.

But it’s important to remember that this device was built back when people were still unironically carrying around flip phones. Detecting laser and multi-band radars might sound like something pulled from the spec sheet of a stealth fighter jet, but this is still a piece of consumer electronics from more than a decade in the past. So let’s crack it open and take a look at what goes on inside a radar detector that’s only a few years away from being old enough to get its own driver’s license.

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Clock Uses Custom LED Displays To Keep Myst Time

The Myst fans in the audience will love this project because it displays the 25-hour timekeeping system of the D’ni. The hardware hackers will lean a little closer to their screen because it does so with custom made 25-segment LEDs, and the precision obsessed will start breathing heavily when they hear it maintains an accuracy of 0.001 seconds. As for which of those camps creator [Mike Ando] most identifies with, we can’t say. But we definitely respect his style.

We’ll spare you the in-depth description of the base-25 number system apparently used in the Myst franchise. If you’re interested enough you can click on through to the project’s Hackaday.io page and learn how to actually read the clock. Presumably you’ll then come back here and leave your comment in Klingon.

Let’s instead jump right to the part that really gets us excited, those custom displays. To create them, [Mike] cut the face out of black acrylic with a laser, and filled each void with a mixture of clear resin and very fine gypsum plaster. Getting the mix right can be a little finicky as the plaster can clump up, but the end result diffuses the light nicely. The acrylic front panel and a couple of cardboard “gaskets” to keep the light from leaking onto adjacent segments is then stacked on top of a PCB with corresponding 0603 SMD LEDs.

Beyond the soul-crushing number of wires required to hook everything up internally, the rest of the project is relatively straightforward. It uses a WeMos D1 Mini to connect to the WiFi network and pull the current time down from the geographically closest NTP server every couple of hours. Rather than putting a temperature controlled oscillator on the board, [Mike] has decided to pin his accuracy on a constantly on Internet connection and aggressive synchronizations.

From impressive curved bar graph modules to displays segmented with household items, we’ve seen our fair share of custom indicators. But we have to admit that building 25-segment LED displays for the alphabet of a fictional interstellar species sets the bar pretty high.

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Bask In The Glory Of This 336 LED Digit Display

[Chris Combs] recently took the wraps off of an incredible art piece that he calls Road Ahead which uses 336 seven segment LED digits to create an absolutely gorgeous display. With a piece of smoked acrylic to slightly diffuse the orange glow of the LEDs, the end result has a distinctively retro look that we’d gladly spend all day staring at.

For those looking to dig a bit deeper, [Chris] has put together some very impressive documentation over on Hackaday.io that goes into plenty of detail on how he designed and built this beauty. From the design of the PCBs that carry all of the 0.3″ SMD displays to the custom software running on the Raspberry Pi 3 that powers it, there’s no technical stone left unturned.

According to the build log, this is the second version of the display. The first one was housed in a rather attractive wooden enclosure, but as [Chris] explains, that was precisely the problem. He wanted something that looked cold and unfeeling as the nearly 340 digits flashed away with potentially ominous intent. So he ditched the wooden case for a powder coated steel one that looks more like the front panel of a mainframe than something you’d pick up at the craft store.

Another interesting point explained in the write-up is how the Python software is designed to treat the hardware as a contiguous graphical display rather than just an array of independent digits. Grayscale images can be reproduced on the by using PWM to adjust the brightness of each segment’s corresponding “pixel”; though admittedly it takes a bit of imagination to see the intended image with a resolution this low.

This project reminds us of the incredible LED hexdump display we saw not that long ago, down to the PWM trickery for squeezing “graphics” out of these exceptionally non-graphical elements. With any luck, perhaps these are the opening shots in an arms race to see who can build the largest array of multi-segment LED displays.

A Strange Display Gives Up Its Secrets

Providing a display for a project in 2020 is something of a done deal. Standard interfaces and off-the-shelf libraries for easily available and cheap modules mean that the hardest choice you’ll have to make about a display will probably relate to its colour. Three decades ago though this was not such a straightforward matter though, and having a display that was in any way complex would in varying proportion take a significant proportion of your processing time , and cost a fortune. [AnubisTTP] has an unusual display from that era, a four-digit LED dot matrix module, and the take of its reverse engineering makes for a fascinating read.

The LITEF 104267 was made in 1986, and is a hybrid circuit in a metal can with four clear windows , one positioned over each LED matrix. Inside are seven un-encapsulated chips alongside the LED matrices on a golf plated hybrid substrate. The chips themselves are not of a particularly high-density process, so some high-resolution photography was able to provide a good guess at their purpose. A set of shift registers drive the columns through buffers, while the rows are brought out to a set of parallel lines. Thus each column can be illuminated sequentially with data presented on the rows. It’s something that would have saved a designer of the day a few extra 74-series chips, though we are guessing at some significant cost.

This display may seem antiquated to us today, but it wasn’t the only option for 1980s designers. There’s one display driver from back then that’s very much still with us today.