Core Memory for the Hard Core

[Brek] needed to store 64 bits of data from his GPS to serve as a last-known-position function. This memory must be non-volatile, sticking around when the GPS and power are off. Solutions like using a backup battery or employing a $0.25 EEPROM chip were obviously too pedestrian. [Brek] wanted to store his 64 bits in style and that means hand-wired core memory.

OK, we’re pretty sure that the solution came first, and then [Brek] found a fitting problem that could be solved, but you gotta give him props for a project well executed and well documented.

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Before Arduino There was Basic Stamp: A Classic Teardown

Microcontrollers existed before the Arduino, and a device that anyone could program and blink an LED existed before the first Maker Faire. This might come as a surprise to some, but for others PICs and 68HC11s will remain as the first popular microcontrollers, found in everything from toys to microwave ovens.

Arduino can’t even claim its prominence as the first user-friendly microcontroller development board. This title goes to the humble Basic Stamp, a four-component board that was introduced in the early 1990s. I recently managed to get my hands on an original Basic Stamp kit. This is the teardown and introduction to the first user friendly microcontroller development boards. Consider it a walk down memory lane, showing us how far the hobbyist electronics market has come in the past twenty year, and also an insight in how far we have left to go.

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Turning A Typewriter Into A Mechanical Keyboard

Is your keyboard too quiet? Is your Cherry MX Blue board not driving your coworkers crazy enough? If the machine gun fire of a buckling spring keyboard isn’t enough for you, there’s only one solution: [Russell]’s typewriter turned into a mechanical keyboard.

Converting typewriters into keyboards has been done for a very long time; teletypes, the first computer keyboards, were basically typewriters, and the 1970s saw a number of IBM Selectrics converted into a keyboard with serial output. Even in recent years, typewriters have been converted into keyboards with the help of some switches and an ATMega. [Russell]’s mechanical keyboard improves on all of these builds by making the electronic interface dead simple, and a project that can be done by anyone.

Instead of installing switches underneath every key or futzing about with the weird mechanics of a Selectric typewriter, [Russell] is only installing a touch-sensitive position sensor into the frame of the typewriter. When a key is pressed, it strikes a crossbar in the frame of the typewriter. With a single ADC chip and a Raspberry Pi, [Russell] can determine which key was pressed and use that information to output a character to a terminal.

It’s a very simple solution for an electrical interface to a mechanical device, and the project seems to work well enough. [Russell] is using his new keyboard with Vim, even, something you can check out in the video below.

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You Can Have my TIPs When You Pry them from my Cold, Dead Hands

We’ve seen a growing number of posts and recommendations around the net regarding components, specifically transistors. “Don’t use old parts” they cry,  “Go with newer components.”  You can often find these recommendations on Arduino forums. This all came to a head with a page called “Do Not TIP,” which was linked in the Arduino subreddit.  This page belongs to [Tom Jennings], creator of Fidonet, and one of the early authors of what would become Phoenix BIOS. [Tom] and a few others have been calling for everyone to send their old parts to the landfill – not use them, nor gift them to new experimenters. Get them out of the food chain. No offense to [Tom], but we have to disagree. These parts are still perfectly usable for experienced designers, and have a lot to offer new hardware hackers.

TIP is the part number prefix for a series of power transistors created by Texas Instruments.  In fact, “TIP” stands for Texas Instruments Power. The series was originally released in 1969. Yes, that’s right, 1969. Why are we still using parts designed when man first walked on the moon? The same reason people are still using the 555 timer: they’re simple, they’re easily available, they’re robust, and most of all, they get the job done. The TIP series has been used in thousands of classes, tutorials both online and off, and millions of projects over the years. Much of that documentation is already out there on the internet. The TIP series is also out in the distribution channel – they’ve been used for 40 years. Any retail shop that stocks a few electronics parts will have at least one of the TIP series.

The TIP series aren’t always the best transistors for the job. However, for most hobbyist-designed circuits, we don’t need the best performance, nor the best price – we’re going to use the parts we have on hand. There is always room to improve once you get the basic circuit working.

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Commodore C16 Resurrection with a Raspberry Pi

[lactobacillusprime] had a non-working Commodore C16 and too many Raspberry Pi computers, so he decided to bring the C16 back to life by emulating it on the Pi. At the heart of the project is the Pi, along with a small board that converts the old style Commodore keyboards (and joysticks) to a USB port.

Once you have the keyboard as a USB port, the rest of the project is more or less mechanics and software. [lactobacillusprime] did a nice job of getting everything in the new case, along with all the I/O wires routed through the existing ports. For software, Emulation Station does the job of launching the Commodore emulation on the Pi.

Of course, there’s no reason to limit yourself to just the Commodore emulator. Emulation Station along with the right back end emulators will allow this machine to play games that no real Commodore C16 could.

Of course, we were happiest to see him boot up Commodore 64 BASIC. Perhaps we should complete all those half finished C64 BASIC projects we started back in the 1980’s. In general, we hate to see old computers gutted instead of repaired, but at least this one will continue running its software. If you are upset about seeing a machine gutted,  you can always switch over to our previous coverage of putting Commodore guts in a new box.

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Crack Open a USB Car Charger to make it a Variable DC-DC Converter

[Boolean90] hacked a cheap USB car charger into a variable power supply. His proof of concept is to use this as a variable-speed motor controller. The best part is that nothing is being abused, the regulator inside is still running within manufacturer’s spec.

While we’ve seen similar hacks before, [Boolean90]s video is pretty cool and provides a nice insight into the components used in these cheap devices. Rather than a linear regulator, which would dissipate too much heat the device uses a common jelybean MC34063A (PDF) switching DC-DC converter which costs about 10 cents on eBay (about two dollars for twenty, shipped). Here it’s used to step the car batteries 12 volts down to 5, but can also be used in step-up and inverting configurations.

Like all switching buck converters the MC34063A uses a PWM (pulse width modulated) signal to drive an inductor and capacitor, which effectively form an LC filter. By controlling the pulse width, the output voltage can be regulated. [Afrotechmods] has a great tutorial on the basic principle. The regulation is controlled by feedback resistors. [Boolean90] simply added a variable resistor to allow the output voltage to be controlled.

Neat hack [Boolean90]! Continue reading “Crack Open a USB Car Charger to make it a Variable DC-DC Converter”

Emulating a Hard Drive With The Raspberry Pi

[Chris] recently moved a vintage IBM 5150 – the original PC – into his living room. While this might sound odd to people who are not part of the Hackaday readership, it actually makes a lot of sense; this PC is a great distraction-free writing workstation, vintage gaming machine, and looks really, really cool. It sat unused for a while, simply because [Chris] didn’t want to swap out piles of floppies, and he doesn’t have a hard drive or controller card for this machine. After reviewing what other retrocomputer fans have done in this situation, he emulated a hard drive with a Raspberry Pi.

The traditional solution to the ‘old PC without a hard drive’ problem is the XTIDE project. XTIDE is a controller card that translates relatively new IDE cards (or an emulated drive on another computer) as a hard drive on the vintage PC, just like a controller card would. Since a drive can be emulated by another computer, [Chris] grabbed the closest single board computer he had on hand, in this case a Raspberry Pi.

After burning an EPROM with XTIDE to drive an old network card, [Chris] set to work making the XTIDE software function on the Raspberry Pi side of things. The hardware on the modern side of the is just a Pi and a USB to RS232 adapter, set to a very low bitrate. Although the emulated drive is slow, it is relatively huge for computer of this era: 500 Megabytes of free space. It makes your head spin to think of how many vintage games and apps you can fit on that thing!