Overclocking The Raspberry Pi 3 For Tasty Speed Increases

March 3, 2016 by Richard Baguley 47 Comments

Some people are never happy. [Jackenhack] got hold of a couple of shiny new Raspberry Pi 3s, and the first thing he did is to start overclocking them. Fortunately, he knows what he is doing, so none of the magic smoke escaped, but it seems not all Pis are happy with the process.

For one of the three seemingly identical Pi 3, adding heat sinks let him push the CPU from the native 1.2GHz up to 1.45GHz. That did involve a bit of overvolting (increasing the voltage to the CPU), but that can be easily done in software. He also experimented with adding heat sinks to the memory, then bumping up the speed of the memory to increase throughput. Again, he was able to make some impressive gains, bumping the speed up from the native 400 Mhz to 500 Mhz. Both of those are stable overclocks: he was able to run the system at 100% CPU load for an extended time, and has incorporated the overclocked Pi into his system that contributes to the NTP pool project.

However, when he tried the same overclock with the second of the Pi 3 ~~victims~~ test subjects, it failed due to the CPU overheating. So, it seems that there is a lot of variation in the individual bits of silicon on the Pi 3. Perhaps some liquid nitrogen would help? It did for an Arduino…

Hack A PS/2 Keyboard Onto Your Pi Zero

March 2, 2016 by Elliot Williams 31 Comments

Hacking for the Raspberry Pi Zero is a tricky proposition. Whatever you do, you’re working with a nominal five dollar board, so your hacks can’t be too highfalutin. For instance, a decent PS/2 to USB adapter will cost you as much as the Zero did, if not more. But if you just need to drive your Pi Zero from your old Model M (we hear you!) you’ve got to do it on the cheap.

So when prolific Pi hacker [mincepi] set out to build a PS/2 adapter, some corners were cut. PS/2 is a clocked data protocol, but the good news is that the clock doesn’t start and stop all the time as in I2C or SPI. This means that if you poll the data line at just the right frequency, at least in principle you’ll be able to ignore the clock.

So that’s what [mincepi] did. As you can see in the schematic and the banner image, there’s nothing to it. Two resistors provide the pullup voltage for the clock and data lines. And here’s a gem: a green LED with a drop voltage of about 2 V converts the 5 V data line down to something that the Pi Zero’s 3.3 V won’t get fried with. Cute, and very much in keeping with the spirit of the hack. You might be tempted to scrounge up a 3.3 V zener diode from somewhere just to be on the safe side, but remember, it’s a five dollar computer you’re protecting.

The last piece is a custom kernel module for the Pi that polls the PS/2 data line at just the right frequency. If you’re not a Linux person and “compiling a kernel module” sounds scary, [mincepi] has even put together a nice guide for the Raspbian distribution that he’s using. It should work with minor tweaks for any other distro.

We said [mincepi] is a prolific Pi hacker and here’s the proof: we’ve covered his quick-and-dirty VGA output hack and a scheme to get analog sound input into the Pi Zero just in the last couple of weeks. Hack on!

Star Trek Pi

March 1, 2016 by Al Williams 26 Comments

Every time we yell out, “OK Google… navigate to Velvet Melvin’s” we feel like a Star Trek character. After all, you’ve never seen Captain Kirk (or Picard) using a keyboard. If you get that same feeling, and you have a Raspberry Pi project in mind, you might enjoy the Raspberry Pi LCARS interface.

You can see the results in the video below. The interface uses PyGame, and you can customize it with different skins if you don’t want a Star Trek look.

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Pi 3 Benchmarks: The Marketing Hype Is True

March 1, 2016 by Brian Benchoff 123 Comments

The spec bullet list for the latest Raspberry Pi begins as you’ve already heard: WiFi and Bluetooth, now standard. While this is impressive itself, it doesn’t tell the whole story. The Pi 3, with an ARM Cortex A53, is up to 50% faster than the Pi 2 from last year. That’s an astonishing improvement in just 12 short months.

In playing with the Pi 3 for a few hours, it’s apparent the Pi 3 is fast. It passes a threshold of usability. The Raspberry Pi isn’t a computer that just sits on a shelf and runs a few cron jobs and blinks LEDs anymore – this is a computer that’s usable as a computer. But how fast is it? By stroke of luck, the official website for the Cortex A53 gives us a direct comparison between this chip and the CPU in the Raspberry Pi 2:

In real devices, the performance improvement from the Pi 2 to the Pi 3 is somewhere between 40 and 60 percent. At least that’s what ARM and the Raspberry Pi foundation are claiming. Is this true? There are tests we can run, and the marketing speak, for once, isn’t too terribly off the mark.

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Introducing The Raspberry Pi 3

February 28, 2016 by Brian Benchoff 250 Comments

TL;DR: The Raspberry Pi 3 Model B is out now. This latest model includes 802.11n WiFi, Bluetooth 4.0, and a quad-core 64-bit ARM Cortex A53 running at 1.2 GHz. It’s a usable desktop computer. Available now at the usual Pi retailers for $35.

News of the latest Raspberry Pi swept around the Internet like wildfire this last weekend, thanks to a published FCC docs showing a Pi with on-board WiFi and Bluetooth. While we thank the dozens of Hackaday readers that wrote in to tell us about the leaked FCC documents, our lips have been sealed until now. We’ve been doing a few hands-on tests with the Pi 3 for about two weeks now, and the reality of the Pi 3 is much cooler than a few leaked FCC docs will tell you.

The Raspberry Pi 3 Model B features a quad-core 64-bit ARM Cortex A53 clocked at 1.2 GHz. This puts the Pi 3 roughly 50% faster than the Pi 2. Compared to the Pi 2, the RAM remains the same – 1GB of LPDDR2-900 SDRAM, and the graphics capabilities, provided by the VideoCore IV GPU, are the same as they ever were. As the leaked FCC docs will tell you, the Pi 3 now includes on-board 802.11n WiFi and Bluetooth 4.0. WiFi, wireless keyboards, and wireless mice now work out of the box.

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$79 Smart Mirror Uses Raspberry Pi

February 28, 2016 by Al Williams 17 Comments

[Nathan] wanted a smart mirror that cost less than the last one he built, which was about $500. He decided that you don’t see more smart mirrors because of the high cost. His latest build came in at only $79 (you’ll have to visit the blog’s home page to find the entire series).

The most expensive piece of the build is a 7-inch monitor ($45). Any Raspberry Pi will work, although [Nathan] uses a Pi B+. Although he managed to score a free one-way mirror from a local glass shop, you can buy one for about $13.

This is the kind of project that isn’t a big technical challenge. After all, it is a one-way mirror with an LCD screen behind it. However, getting the screen blacked out and set to provide the best possible effect is the trick and [Nathan’s] techniques will give you a head start.

You can see the mirror in the video below. We’ve seen smart mirrors that sense your presence as well as wireless mirrors before.

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Rasberry Pi Analog Input Using Only Passive Components

February 28, 2016 by Jenny List 18 Comments

The Raspberry Pi is a very capable device whose hardware has been pushed to the limit in all sorts of interesting ways. But even the most ingenious of experimenters have to agree on one point; it doesn’t possess an analog-to-digital converter. If you want analog inputs you will have to buy or build them.

[Mincepi] has done just that, but not as you might expect by adding an integrated circuit on one of the Pi’s interfaces. Instead the circuit [Mincepi] is using consists only of passive components, measuring the time taken to discharge the parasitic capacitance of one of the Pi’s inputs from logic 1 voltage to logic 0 voltage through a resistor into the voltage to be measured. This is a long-established approach to A to D conversion, one that was achieved back in the day with purpose-designed timers as microprocessor ancillaries.

The problem is that the Pi does not have a timer peripheral, so [Mincepi] has used the shift registers that form part of the Pi’s SPI and PCM inputs to perform this task on two channels. A sample rate of 100kHz and 6-bit resolution is claimed, with enough voltage range for a 1V peak-to-peak audio signal to be sampled.

Of course, simplicity does not guarantee a good ADC, and this circuit does not perform very well. It is noisy, non-linear, and as [Mincepi] puts it, probably sensitive to temperature. And though [Mincepi] talks in detail about the software to drive it, none is forthcoming. To quote: “It doesn’t include code since I’m in the process of writing a proper sound device module. My previous code was a simple character device, but it worked just fine, and served to prove the concept.”

We really want this to work, even if it’s not the best ADC ever. So we eagerly await the sound device module, and look forward to more news from the project.

This may be the simplest of simple ADCs we’ve yet featured here on Hackaday, but it’s not the first we’ve seen. There is this one using a comparator for example, or this one using a flip-flop. It is the essence of creative electronics to eke a function from a component that was never meant to be, please keep them coming!