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5118 Articles

Kids And Hacking: Blind Robotics

September 10, 2015 by 21 Comments

If you are a Hackaday reader, it is a good bet that when you were a kid there was some adult who infected you with the madness you have for science, engineering, tinkering, or whatever it is that brings you here. Maybe it was a parent or a teacher. For many of us, it was a local ham radio operator. But it was probably someone who had the passion for this kind of thing and you caught it.

Paying that debt forward can be very rewarding. Schools and youth organizations are always looking for people to share their passions with kids and at the right age and the right school, you could be that one push that moves a kid off a bad path.

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Video FPGA With No External A/D

September 9, 2015 by 23 Comments

You have an old PC with a nonstandard RGB video out and you need to bring it to a modern PAL TV set. That’s the problem [svofski] had, so he decided to use an Altera-based DE1 board to do the conversion. Normally, you’d expect reading an RGB video signal would take an analog to digital converter, which is not typically present on an FPGA. Instead of adding an external device, [svofski] used a trick to hijack the FPGA’s LVDS receivers and use them as comparators.

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See Actual Microwaves — No More Faking It

September 8, 2015 by 51 Comments

Last week we saw a lot of interest in faux visualization of wireless signals. It used a tablet as an interface device to show you what the wireless signals around you looked like and was kind of impressive if you squinted your eyes and didn’t think too much about it. But for me it was disappointing because I know it is actually possible to see what radio waves look like. In this post I will show you how to actually do it by modifying a coffee can radar which you can build at home.

The late great Prof. David Staelin from MIT once told me once that, ‘if you make a new instrument and point it at nature you will learn something new.’ Of all the things I’ve pointed Coffee Can Radars at, one of the most interesting thus far is the direct measurement and visualization of 2.4 GHz radiation which is in use in our WiFi, cordless phones (if you still have one) and many other consumer goods. There is no need to fool yourself with fake visualizations when you can do it for real.

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Pulse Density Modulation

September 8, 2015 by 34 Comments

[esot.eric] was trying to drive a motor and naturally thought of using pulse width modulation (PWM) to control the motor speed. However, he found that even with a large capacitor, his underpowered power supply would droop before the PWM cycles were complete. So instead of PWM he decided to experiment with pulse density modulation.

The idea is to use smaller pulses over a longer period of time and make the average power equal to the percentage motor speed desired. With a PWM system, for example, if the time period is T, a 50% PWM drive would have the  drive high for T/2 and low for the other half of the cycle. With pulse density, each pulse might be T/10 (as an example) and then the output would be on for 1/10, off for 1/10, on for 1/10 and so on, until by time T you’d still get to 50%. The advantage is the output capacitor gets a kick more often and has less opportunity to droop.

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The Rise Of The Rural Hacker

September 7, 2015 by 56 Comments

On the far side of the Boso peninsula lies Kamogawa. This isn’t the Japan of LEDs, Otaku and maid cafes, or that of wage slave salarymen collapsing from exhaustion. This is the Japan of rice farmers and fields, fresh fish and wild boar, electron microscopes and gigabit fiber, SMD assembly and 500Mhz 5 Gigasample oscilloscopes.

The world has changed. In the 20th century the life of a rural hacker was a constant hunt for technological innovation. We scratched around for whatever we could find. A (usually national) periodical would give its monthly injection of technological curios. And knowledge was locked tight within expensive textbooks, which even if you could afford them might take weeks to arrive.

So, as had been the case for the preceding 1000 years, innovation clustered around technological hubs, San Francisco, Cambridge, and Tokyo among others. And Hackers flocked to these centers where innovation flourished while Hackers exchanged knowledge and tools.

But then the world of the rural Hacker began to expand. The technological hubs that so many rural hackers had migrated to began to connect the world. Young Hackers could learn to program (as I learned C) from textfiles posted on BBSs and exchange knowledge linking national communities. Shortly after that the Internet came bringing its Eternal September. Hackers across the world, regardless of location could communicate.

On the flip-side tech centers were changing too. Venture capital, rather than bootstrapping became the norm. With the influx of cash the demand for skilled Hackers rose, increasing wages and further focusing tech talent around these hubs. But rents and expenses rose too. And Hackers became locked into their expensive lifestyles; eyes firmly focused on the promised million dollar payoff and the eternal dream of an “exit”.

For some though, the freedom to Hack is more important than that million dollar exit and so a new model is emerging. Groups of Hackers in rural communities with low cost lifestyles and access to the world’s best technical talent and equipment that would put the best startups to shame.

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Orange Is The New ($15) Pi

September 5, 2015 by 105 Comments

When the Raspberry Pi came on the scene it was hard to imagine that you could get a fairly complete Linux system for such a low price. The Pi has gotten bigger, of course, but there are still a few things you miss when you try to put one into a project. Wifi, comes to mind, for example. The first thing you usually do is plug a Wifi dongle in, consuming one of the two USB ports.

The Orange Pi is a direct competitor and has a few variants. Originally, the board cost about $30 but sports WiFi, a 1.6 GHz processor, 8 GB of flash, and a SATA interface. There’s now a reduced version of the board for about $15 that deletes the flash and SATA along with the WiFi and one of the original’s 4 USB ports. Still, the Raspberry Pi doesn’t have built-in flash. And the $15 Orange Pi PC has the things you’d expect on a Pi (HDMI and Ethernet) along with other extras like an IR receiver and an on-board microphone. Not bad for $15 considering it has a quad-core processor, a GPU and 1GB of RAM. Continue reading “Orange Is The New ($15) Pi” →

How To Build Anything Using Delrin And A Laser Cutter

September 3, 2015 by 58 Comments

Need a simple fab process to go from a humble vector graphic to a final part — in a matter of minutes? The CO2  laser cutter might be the right choice. As these tools open themselves up to widespread use through hackerspaces, I decided to give Delrin some well-deserved time under the spotlight.

The laser cutter yet-again proves itself a formidable tool with the construction of GameCube-Bot V2

This guide is a brief collection of tips and techniques that I’ve either learned from others or discovered on my own over the last couple years working with laser-cut Delrin (a.k.a Acetal) for functional prototypes. I hope this guide serves you well as we keep exploring the limits of the material.

As a disclaimer, keep in mind that in no way are these techniques unique or limited to Delrin. Many are not only years old but also common practice in either engineering design or the local machine shop. This article simply highlights the techniques shown here that perform both repeatably and predictably with Delrin and a couple hand-tools, and I hope to share them with a growing audience of laser cutter enthusiasts.

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