[Fran]‘s LEDs, Nixies, and VFDs.

FRAN LED

With a love of blinky and glowey things, [Fran] has collected a lot of electronic display devices over the years. Now she’s doing a few teardowns and tutorials on some of her (and our) favorite parts: LEDs and VFD and Nixie tubes

Perhaps it’s unsurprising that someone with hardware from a Saturn V flight computer also has a whole lot of vintage components, but we’re just surprised at how complete [Fran]‘s collection is. She has one of the very first commercial LEDs ever made. It’s a very tiny red LED made by Monsanto (yes, that company) packaged in a very odd lead-and-cup package.

Also in her LED collection is a strange Western Electric part that’s green, but not the green you expect from an LED. This LED is more of an emerald color – not this color, but more like the green you get with a CMYK process. It would be really cool to see one of these put in a package with red, green, and blue LED, and could have some interesting applications considering the color space of an RGB LED.

Apart from her LEDs, [Fran] also has a huge collection of VFD and Nixie tubes. Despite the beliefs of eBay sellers, these two technologies are not the same: VFDs are true vacuum tubes with a phosphorescent coating and work something like a CRT turned inside out. Nixies, on the other hand, are filled with a gas (usually neon) that turns to plasma when current flows through one of the digits. [Fran] has a ton of VFDs and Nixies – mostly military surplus – and sent a few over to [Dave Jones] for him to fool around with.

It’s all very cool stuff and a great lead-in to what we hear [Fran] will be looking at next: electroluminescent displays found in the Apollo Guidance Computer.

Videos below.

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Build an Audio Spectrum Analyzer the Analog Way

bandpass

[Ryan] wanted a spectrum analyzer for his audio equipment. Rather than grab a micro, he did it the analog way. [Ryan] designed  a 10 band audio spectrum analyzer. This means that he needs 10 band-pass filters. As the name implies, a band-pass filter will only allow signals with frequency of a selected band to pass. Signals with frequency above or below the filter’s passband will be attenuated. The band-pass itself is constructed from a high pass and a low pass filter. [Ryan] used simple resistor capacitor (RC) filters to implement his design.

All those discrete components would quickly attenuate [Ryan's] input signal, so each stage uses two op-amps. The first stage is a buffer for each band. The second op-amp, located after the band-pass filters, is configured as a non-inverting amplifier. These amplifiers boost the individual band signals before they leave the board. [Ryan] even added an “energy filler” mode. In normal mode, the analyzer’s output will exactly follow the input signal. In “energy filler” (AKA peak detect) mode, the output will display the signal peaks,  with a slow decay down to the input signal. The energy filler mode is created by using an n-channel FET to store charge in an electrolytic capacitor.

Have we mentioned that for 10 bands, all this circuitry had to be built 10 times? Not to mention input buffering circuitry. With all this done, [Ryan] still has to build the output portion of the analyzer: 160 blue LEDs and their associated drive circuitry. Going “all analog” may seem crazy in this day and age of high-speed micro controllers and FFTs, but the simple fact is that these circuits work, and work well. The only thing to fear is perf board solder shorts. We think debugging those is half the fun.

Inside The Clapper

clapper

Hackaday readers above a certain age will probably remember the fabulously faddish products developed by Joseph Enterprises. These odd gadgets included the Ove’ Glove, VCR Co-Pilot, the Creosote Sweeping Log, and Chia Pet (Cha-Cha-Cha-Chia) as mainstays of late night commercials, but none were as popular as The Clapper, everyone’s favorite sound-activated switch from the 1980s. [Richard] put up a great virtual teardown of The Clapper, that provides a lot of insight into how this magic relay box actually works, along with some historical context for the world The Clapper was introduced to.

Sound activated switches are nothing new, but the way The Clapper did it was just slightly brilliant. Instead of listening to every sound, the mic inside the magic box sends everything through a series of filters to come up with a very narrow bandpass filter centered around 2500 Hz. This trigger is analyzed by a SGS Thompson ST6210 microcontroller ( 4MHz, ~1kB ROM, 64 bytes of RAM, and 12 I/O pins ) to listen for two repeating triggers  within 200 milliseconds. The entire system – including the source code for the MCU – can be seen in the official patent, US5493618.

The Clapper sold many millions of units at a time when a lot of homes were assuredly in a pre-microelectronics world. Yes, in 1986, a lot of TVs had microcontrollers and maybe a washer/dryer combo may have had a few thousand transistors between them. Other than that, The Clapper was many household’s introduction to the ubiquitous computing power we see today, and all with less capability than an Arduino.

Hackaday Retro Roundup: Ultraportables edition

front

A few months ago, we rolled out an updated Hackaday, a badly needed new layout replacing the HTML and CSS that had remained unchanged since 2004. Of course a few people didn’t like change and complained about slow load times. We’ve experienced a slightly slower load time as well, so we’ll just wait until the year 2020 when our computers are many times faster and our Internet is provided by Google Fiber. Until then, our pokey battlestations and vintage computers can still check out a few classic hacks on our retro site. Here’s a few retro successes – Hackaday readers who pulled out their old tech and loaded up the retro site – that have come in over the past weeks and months.

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Making a nostalgic Apple mouse wireless

If you’ve got an old mouse sitting around that has that perfect retro look why not start using it again? We’d bet there’s just enough room in there to turn the input device wireless.

The hack does away with everything but the case. The guts from a brand new wireless laser mouse are used as replacements. For the most part this is a simple process of making room for the new board and laying it in place. It involves cutting off a few plastic case nubs, enlarging the hole on the bottom so that the laser has a clear line of sight to the desktop, and hot gluing the thing in place. The button cover had a bit of plastic glued in place so that it lines up correctly with the replacement mouse’s switch.

The only thing that didn’t work out well is the battery situation. The AA cell that the mouse needs was too big for the retrofit so it was swapped with an AAA. These have a lower capacity which means more frequent replacement.

[via Make]

Adding Compact Flash to an old sequencer

[Shoji] has a beloved sequencer that went out of production ten years ago. Unfortunately the storage options are also 10 year out-of-date as SCSI is the stock option for storing his loops. Using a series of adapters he added Compact Flash storage to his Akai MPC-2000 Classic. The board has a connector for 25-pin SCSI which he wired to a 25-pin to 50-pin SCSI adapter. From there he connects a SCSI to IDE board, and then an IDE to CF. Subsequent versions of the Akai Classic have floppy drives in the front left corner so he used this method to mount he CF slot. Now he’s got plenty of storage with very little change to the appearance of the looper.

Just the right controller for any game

[Patrice] hacked all of his classic controllers for use when playing games on an emulator. He made the base station starting with a USB gaming controller. From there he soldered wires connecting the PCB pads for all of the buttons to the pins of a d-sub connector. The same is done on the classic controller, allowing him to switch them out at will. If you do the wiring correctly you only need to configure your emulator buttons once. This is a lot easier than trying to find and use classic controller connectors but you do have to alter that vintage hardware.