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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Hackaday Prize Entry: From Q To NAND

The apocalypse is coming, and the last time I checked, not many people have a semiconductor fab in their garage. We’ll need computers after the end of the world, and [matseng]’s project for the Hackaday Prize is just that – a framework to build computers out of discrete components.

The apocalyptic spin on this project is slightly exaggerated, but there is a lot someone can learn by building digital devices out of transistors, resistors, and diodes. The building blocks of [matseng]’s computer are as simple as they come: he’s using three resistors, four diodes, and one NPN transistor to build a single NAND gate. These NAND gates can then be assembled into any form of digital logic. You’re never going to get a better visual example of functional completeness.

A project like this must be approached from both the top down and bottom up. To go from a high level to ones and zeros, [matseng] built an assembler and an emulator. Some ideas of what the instruction set will be are laid out in this project log, and for now [matseng] is going for a Harvard architecture with eight registers. It’s a lot of work for a computer that will be limited by how much memory [matseng] can be wired up, but as far as ambition goes, there aren’t many projects in the Hackaday Prize that can match this tiny, huge computer.

The 2015 Hackaday Prize is sponsored by:

Discrete Transistor Computer Is Not Discreet

Every few years, we hear about someone building a computer from first principles. This doesn’t mean getting a 6502 or Z80, wiring it up, and running BASIC. I’m talking about builds from the ground up, starting with logic chips or even just transistors.

[James Newman]’s 16-bit CPU built from transistors is something he’s been working on for a little under a year now, and it’s shaping up to be one of the most impressive computer builds since the days of Cray and Control Data Corporation.

The 10,000 foot view of this computer is a machine with a 16-bit data bus, a 16-bit address bus, all built out of individual circuit boards containing single OR, AND, XOR gates, decoders, multiplexers, and registers.  These modules are laid out on 2×1.5 meter frames, each of them containing a schematic of the computer printed out with a plotter. The individual circuit modules sit right on top of this schematic, and if you have enough time on your hands, you can trace out every signal in this computer.

The architecture of the computer is more or less the same as any 16-bit processor. Three are four general purpose registers, a 16 bit program counter, a stack pointer, and a status register. [James] already has an assembler and simulator, and the instruction set is more or less what you would expect from a basic microprocessor, although this thing does have division and multiplication instructions.

The first three ‘frames’ of this computer, containing the general purpose registers, the state and status registers, and the ALU, are already complete. Those circuits are mounted on towering frames made of aluminum extrusion. [James] already has 32 bytes of memory wired up, with each individual bit having its own LED. This RAM display will be used for the Game of Life simulation once everything is working.

While this build may seem utterly impractical, it’s not too different from a few notable and historical computers. The fastest computer in the world from 1964 to ’69 was built from individual transistors, and had even wider busses and more registers. The CDC6600 was capable of running at around 10MHz, many times faster than the estimated maximum speed of [James]’ computer – 25kHz. Still, building a computer on this scale is an amazing accomplishment, and something we can’t wait to see running the Game of Life.

Thanks [aleksclark], [Michael], and [wulfman] for sending this in.

Increasing The Brightness Of A Philips LivingColors Lamp

[Martin] recently purchased a Philips LivingColors lamp. It’s a commercial product that basically acts as mood lighting with the ability to change to many different colors. [Martin] was disappointed with the brightness of his off-the-shelf lamp. Rather than spend a few hundred dollars to purchase more lamps, he decided to modify the one he already had.

[Martin] started by removing the front cover of his lamp. He found that there were four bright LEDs inside. Two red, one green, and one blue. [Martin] soldered one wire to the driver of each LED. These wires then connected to four different N-channel MOSFET transistors on a piece of protoboard.

After hooking up his RIGOL oscilloscope, [Martin] was able to see that each LED was driven with a pulse width modulated signal. All he had to do was connect a simple non-addressable RGB LED strip and a power source to his new driver board. Now the lamp can control the LED strip along with the internal LEDs. This greatly extends the brightness of the lamp with minimal modifications to the commercial product. Be sure to check out the video below for a complete walk through. Continue reading “Increasing The Brightness Of A Philips LivingColors Lamp”

Adding A Backlight To A Cheap Multimeter

We don’t all need super high quality electronic testing gear. Sometimes second-hand or inexpensive equipment is accurate enough to get the job done. Though it can be a bit annoying to miss out on some of those “luxury” features. [Ekriirke] had this problem with his cheap multimeter. He wished the LCD screen had a backlight for easier visibility, so rather than upgrade to a more expensive unit he just added one himself.

After opening up the multimeter [Ekriirke] found that it ran on a single 12V battery. He realized that the simplest thing to do would be to wire up four white LEDs in series. The four LEDs were arranged within the case off to each side of the LCD, one in each corner. The leads were bent at 90 degree angles and soldered together “dead bug” style. Thin strips of copper foil tape were attached to the PCB in such a way that the anode and cathode from the LEDs would make contact when the case was closed back up.

The tape wraps around to the other side of the PCB where there was more room for the next piece of the circuit. A capacitor, resistor, and transistor are used in conjunction with a momentary switch. This circuit allows [Ekriirke] to turn on the light for about ten seconds by pressing the button one time. The circuit also runs through the meter’s dial switch, preventing the LEDs from being turned on while the meter itself is turned off.

[via Reddit]

Retrotechtacular: The Genesis of the Transistor

Few births are easy. Even fewer result in a Nobel Prize, and hardly any at all are the work of three men. This 1965 film from the AT&T archives is a retrospection on the birth of the transistor nine years after its creators, [Walter Brattain], [John Bardeen], and [William Shockley] received a Nobel Prize in Physics for their discovery and implementation of the transistor effect.

The transistor is the result of the study of semiconductors such as germanium. Prior to the research that led directly to the transistor, it was known that the conductivity of semiconductors increases when their temperature is raised. The converse is true for metals such as tungsten. Semiconductor conductivity also increases when they are exposed to light. Another key to their discovery is that when a metal such as copper is in contact with a semiconductor, conductivity is less in one direction than the other. This particular property was exploited in early radio technology as seen in crystal radios, for copper oxide rectifiers used in telephony, and for microwave radar in WWII.

After WWII, AT&T’s Bell Labs put a lot of time and research into the study of semiconductors, as their properties weren’t fully understood. Researchers focused on the simplest semiconductors, silicon and germanium, and did so in two areas: bulk properties and surface properties. During this time, [Shockley] proposed the field effect, supposing that the electrons near the surface of a semiconductor could be controlled under the influence of an external electric field.

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What’s inside a 555?


The 555 timer chip is a ubiquitous piece of technology that is oft-considered the hardcore way of doing things. Of course, the old timers out there will remind us that discrete transistors are the badass way of doing things, and tubes even more so. It’s not quite at the level of triodes and transformers, but Evil Mad Scientist’s discrete 555 kit is still an amazing piece of kit.

Instead of transistors and resistors etched into silicon as in the OG 555, [Windell] over at EMS turned the basic circuit inside a 555 into a mega-sized version using discrete components. Your parts bins need new scale if you’re going to work with this and other up-scaled hobby electronic components.

Although the integrated stand that makes the whole package look like an overgrown DIP doesn’t break out the signals on the board, it does include some neat screw terminals for alligator clips and bits of wire so this kit can be used in a circuit. Because it uses discrete components, you can also take a meter or scope to check out how a 555 chip works from the inside.