Faking TV Remote Control With Paper And A Lighter

February 7, 2017 by Steven Dufresne 114 Comments

Cut slots into a piece of paper to represent the IR remote control bitstream for putting your TV into standby. Insert it between your TV’s IR receiver and the flame from a lighter, and pull the slots along to generate the coded pattern. Get it just right and you have a paper and lighter remote control. That’s just what [ViralVideoLab] did and you can see it in action in the video below.

Think of this as just the germ of an idea. Imagine how you’d automate this and extend it to include more commands. A wheel with the various bitstreams cut into the circumference comes to mind. A servo would turn the wheel to the desired command and something else would fire up the lighter just as the slots pass by. Now take it a little further. You already have a remote control with keypad and IR light. Hack that to talk to a microcontroller which would control the servo and the IR light. And there you go. A useless but fun hack (hint hint).

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No-Etch: The Proof In The Bluetooth Pudding

February 2, 2017 by Elliot Williams 40 Comments

In a previous episode of Hackaday, [Rich Olson] came up with a new no-etch circuit board fabrication method. And now, he’s put it to the test: building an nRF52 Bluetooth reference design, complete with video, embedded below.

The quick overview of [Rich]’s method: print out the circuit with a laser printer, bake a silver-containing glue onto the surface, repeat a few times to get thick traces, glue the paper to a substrate, and use low-temperature solder to put parts together. A potential drawback is the non-negligible resistance for the traces, but a lot of the time that doesn’t matter and the nRF52 reference design proves it.

The one problem here may be the trace antenna. [Rich] reports that it sends out a weaker-than-expected signal. Any RF design folks want to speculate wildly about the cause?

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Op Amps Combine Into Virtual Ball In A Box

January 28, 2017 by Dan Maloney 14 Comments

What happens when you throw a ball into a box? In the real world, the answer is simple – the ball bounces between the walls and the floor until it eventually loses energy and comes to rest. What happens when you throw a virtual ball into a virtual box? Sounds like something you might need a program running on a digital computer to answer. But an analog computer built with a handful of op amps can model a ball in a box pretty handily too.

OK, it takes quite a large handful of op amps and considerable cleverness to model everything in this simple system, as [Glen Kleinschmidt] discovered when he undertook to recreate a four-decade-old demonstration project from AEG-Telefunken. Plotting the position of an object bouncing around inside the virtual box is the job of two separate circuits, one to determine the Y-coordinate and bouncing off the floor, and one to calculate the X-coordinate relative to the walls. Those circuits are superimposed by a high-frequency sine-cosine pair generator that creates the ball, and everything is mixed together into separate outputs for an X-Y oscilloscope to display. The resulting simulation is pretty convincing, with the added bonus of the slowly decaying clicks of the relay used to change the X direction each time a wall is hit.

There’s not much practical use, but it’s instructional for sure, and an impressive display of what’s possible with op amps. For more on using op amps as analog computers, check out [Bil Herd]’s “Computing with Analog” article.

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Forth: The Hacker’s Language

January 27, 2017 by Elliot Williams 240 Comments

Let’s start right off with a controversial claim: Forth is the hacker’s programming language. Coding in Forth is a little bit like writing assembly language, interactively, for a strange CPU architecture that doesn’t exist. Forth is a virtual machine, an interpreted command-line, and a compiler all in one. And all of this is simple enough that it’s easily capable of running in a few kilobytes of memory. When your Forth code is right, it reads just like a natural-language sentence but getting there involves a bit of puzzle solving.

robot_forth_had-colors — From Thinking FORTH (PDF)

Forth is what you’d get if Python slept with Assembly Language: interactive, expressive, and without syntactical baggage, but still very close to the metal. Is it a high-level language or a low-level language? Yes! Or rather, it’s the shortest path from one to the other. You can, and must, peek and poke directly into memory in Forth, but you can also build up a body of higher-level code fast enough that you won’t mind. In my opinion, this combination of live coding and proximity to the hardware makes Forth great for exploring new microcontrollers or working them into your projects. It’s a fun language to write a hardware abstraction layer in. Continue reading “Forth: The Hacker’s Language” →

A Heart For His Girlfriend

January 26, 2017 by Elliot Williams 22 Comments

[Decino] made a nice LED animated blinking heart box for his girlfriend. That’s a nice gesture, but more to the point here, it’s a nice entrée into the world of custom hardware. The project isn’t anything more than a home-etched PCB, a custom 3D-printed case, a mess of LEDs and current-limiting resistors, a shift register, and a microcontroller. (OK, we’re admittedly forgetting the Fifth Element.) The board is even single-sided with pretty wide traces. In short, it’s a great first project that ties together all of the basics without any parts left over. Oh, and did we mention Valentine’s day?

Once you’ve got these basics down, though, the world is your oyster. Building almost anything you need is just a matter of refining the process and practice. And if you’ve never played around with shift registers, a mega-blinker project like this is a great way to learn hands-on.

Not everything we write up on Hackaday has to be neural nets and JTAG ports. Sometimes a good beginner project that hits the fundamentals with no extra fat is just the ticket. What’s your favorite intro project?

Ultrasuede Bench Power Supply Got Style

January 26, 2017 by Elliot Williams 15 Comments

From the look of it sitting on his bench, you’d never guess that [3nz01]’s power supply was actually a couple of el-cheapo modules from eBay, but now we all know the dirty truth.

Re-using or re-purposing an enclosure can be a great way to get a project done faster and get on to the next one. In [3nz01]’s case (tee-hee!), it was an old clock with a broken and annoying buzzer that needed to go. The clock was a nice piece of wood, but that Plexiglas front panel just wasn’t cutting it. That’s why it’s good to have a tailor for a father — a suitable piece of ultrasuede wrapped around the plexi makes the build look swank.

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Bench Power Supply Uses Server Voltage Regulator

January 24, 2017 by Dan Maloney 15 Comments

If you stuff a computer into a rack with a bunch of other machines, you’d better make it a tough machine. Server-grade means something, so using server parts in a project, like this high-wattage power supply using server voltage regulators, can take it to the next level of robustness.

But before [Andy Brown] could build this power supply, he had to reverse-engineer the modules. Based on what he learned, and armed with a data sheet for the modules, he designed a controller to take advantage of all the capabilities of them and ended up with a full-featured power supply. The modules are rated for 66 watts total dissipation at 3.3 volts and have a secondary 5-volt output. Using an ATmega328, [Andy] was able to control the module, provide a display for voltage and current, temperature sensing and fan control, and even a UART to allow data logging to a serial port. His design features mainly through-hole components to make the build accessible to everyone. A suitable case is yet to come, and we’re looking forward to seeing the finished product.

Can’t scrape together some of these modules on eBay? Or perhaps you prefer linear power supplies to switched- mode? No worries – here’s a super stable unregulated supply for you.

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