Extreme Pi Overclocking With Mineral Oil

November 30, 2018 by 31 Comments

Liquid cooling is a popular way to get a bit of extra performance out of your computer. Usually this is done in desktops, where a special heat sink with copper tubing is glued to the CPU, and the copper tubes are plumbed to a radiator. If you want dive deeper into the world of liquid cooling, you can alternatively submerge your entire computer in a bath of mineral oil like [Timm] has done.

The computer in question here is a Raspberry Pi, and it’s being housed in a purpose-built laser cut acrylic case full of mineral oil. As a SoC, it’s easier to submerge the entire computer than it is to get a tiny liquid-cooled heat sink for the processor. While we’ve seen other builds like this before, [Timm] has taken a different approach to accessing the GPIO, USB, and other connectors through the oil bath. The ports are desoldered from the board and a purpose-built header is soldered on. From there, the wires can be routed out of the liquid and sealed off.

One other detail used here that  we haven’t seen in builds like this before was the practice of “rounding” the flat ribbon cable typically used for GPIO. Back in the days of IDE cables, it was common to cut the individual wires apart and re-bundle them into a cylindrical shape. Now that SATA is more popular this practice has been largely forgotten, but in this build [Timm] uses it to improve the mineral oil circulation and make the build easier to manage.

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Packing Decimal Numbers Easily

November 30, 2018 by 12 Comments

While desktop computers have tons of computing power and storage, some small CPUs don’t have a lot of space to store things. What’s more is some CPUs don’t do multiplication and division very well. Same can be said for FPGAs. So suppose we are going to grab a bunch of three-digit decimal numbers from, say, a serial port. We want to store as many as we can, and we don’t want to do a lot of math because we can’t, it is slow, or perhaps it keeps our processor awake longer and we want to sleep to conserve power. We want a way to pack the numbers as close to the theoretical maximum as we can but with little or no math.

The simple approach is to store the numbers as ASCII. Great for processing since they are probably in ASCII already. If they aren’t, you just add 30 hex to each digit and you are done. That’s awful for storage space, though, since we can store 999 in 10 bits if it were binary and now we are using 24 bits! Storing in binary isn’t a good option, if you play by our rules, by the way. You need to multiply by 10 and 100 (or 10 twice) to get the encoding. Granted, you can change that to two shifts and an add (8x+2x=10x) but there’s no easy way to do the division you’ll have to do for the decode.

Of course, there’s no reason we can’t just store decimal digits. That’s call binary coded decimal or BCD and that has some advantages, too. It is pretty easy to do math on BCD numbers and you don’t get rounding problems. Some CPUs even have specific instructions for BCD manipulation. However, three digits will require 12 bits. That’s better than 24, we agree. But it isn’t as good as that theoretical maximum. After all, if you think about it, you could store 16 distinct codes in 4 bits, and we are storing only 10, so that 6 positions lost. Multiply that by 3 and you are wasting 18 codes.

But there is a way to hit that ten-bit target without doing any math. Its called DPD or densely packed decimal. You can convert three decimal digits into ten bits and then back again with no real math at all. You could implement it with a small lookup table or just do some very simple multiplexer-style logic which means it is cheap and easy to implement in software or onboard an FPGA.

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New Part Day: The Twenty Five Cent USB Microcontroller (With A Toolchain!)

November 30, 2018 by 40 Comments

Last year, Jiangsu Yuheng Co., Ltd introduced a new microcontroller. The CH554 is a microcontroller with an E8051 core with a 24 MHz clock, a little more than 1 kB of RAM, and a bit more than 14 kB split between the code and data Flash. In short, it’s nothing too spectacular, but it makes up for that with peripherals. It’s got SPI and ADCs and PWM, UARTs, and even a few capacitive touch channels. It’s also a USB device, with some chips in the series able to function as a USB host. You can buy this chip for a quarter through the usual retailers.

Normally, this isn’t huge news. The 8051 is the most copied microcontroller on the planet, and there are probably billions produced each year. Cheap parts are only cheap if your time is free; you’ll usually spend ages trying to digest the datasheet and get a toolchain up and running. That’s where this chip is a little different. There are multiple efforts to bring an Open Source toolchain to this chip. And they’re doing it in Windows and Linux. Someone really cares about this chip.

The current best option for an SDK for this chip comes from Blinkinlabs, with a port of the CH554 SDK from Keil to SDCC. There are real, working code examples for this chip using an Open Source toolchain. Sure, it might just blink a LED, but it’s there. If you can blink a LED, you can do just about anything from there. Programming the chip happens over USB with the ‘official’ WCHISPTool (Windows) or LibreCH551 (command line). The end result is a completely Open Source toolchain to program and upload a hex file to a cheap chip.

There are a few more chips in the CH554 series, ranging from the CH551 in an SOP-16 package to the CH559 in an LQFP48 package, with more features available as the chips get bigger. It’s an interesting chip, with some somehow implementing a USB hub, and could be a very cool chip for some low-level USB hacking.

Buy Or Build An Autonomous Race Car To Take The Checkered Flag

November 30, 2018 by 7 Comments

Putting autonomous vehicles on public roads takes major resources beyond most of our means. But we can explore all the same general concepts at a smaller scale by modifying remote-control toy cars, limited only by our individual budgets and skill levels. For those of us whose interest and expertise lie in software, Amazon Web Services just launched AWS DeepRacer: a complete package for exploring machine learning on autonomous vehicles.

At a hardware level, the spec sheet makes it sound like they’ve bolted their AWS DeepLens machine vision computer on an 1/18th scale monster truck chassis. But the hardware is only the tip of the iceberg. The software behind DeepRacer is AWS RoboMaker, a set of tools for applying AWS to robot development. Everything from running digital simulations on AWS to training neural networks on AWS. Don’t know enough about machine learning? No problem! Amazon has also just opened up their internal training curriculum to the world. And to encourage participation, Amazon is running a DeepRacer League with races taking place both digitally online and physically at AWS Summit events around the world. They’ve certainly offered us a full plate at their re:Invent conference this week.

But maybe someone prefers not to use Amazon, or prefer to build their own hardware, or run their own competitions. Fortunately, Amazon is not the only game in town, merely the latest entry in an existing field. The DeepRacer’s League’s predecessor was the Robocar Rally, and the DeepRacer itself follows the Donkey Car. A do-it-yourself autonomous racing platform we first saw at Bay Area Maker Faire 2017, Donkey Car has since built up its documentation and software tools including a simulator. The default Donkey Car code is fairly specific to the car, but builders are certainly free to use something more general like the open source Robot Operating System and Gazebo robot simulator. (Which is what AWS RoboMaker builds on.)

So if the goal is to start racing little autonomous cars, we have options to buy pre-built hardware or enjoy the flexibility of building our own. Either way, it’s just another example of why this is a great time to get into neural networks, with or without companies like Amazon devising ways to earn our money. Of course, this isn’t the only Amazon project trying to build a business around an idea explored by an existing open source project. We had just talked about their AWS Ground Station offering which covers similar ground (sky?) as our 2014 Hackaday Prize winner SatNOGS.

An Englishman And 48 Gameboys Walk Into A Bar…

November 29, 2018 by 23 Comments

The original Nintendo Gameboy is perhaps one of the most revered platforms for the music known as chiptune. Primarily, artists will use the console with software like LSDJ or Nanoloop to produce their compositions. Some artists will even use two consoles when performing live. However, that’s all fairly quaint as far as [LOOK MUM NO COMPUTER] is concerned.

Back in 2016, a rig was constructed with three Gameboys. With each console having 3 oscillators and a noise channel, this gave plenty of scope. There was even a facility to detune the oscillators for a fatter sound.

Yet there remains a universal human philosophy – more is always better. In this vein, the plan is to create a monster machine consisting of 48 Gameboy consoles. This offers a somewhat maddening 144 oscillators and 48 noise channels to play with. The plan is to produce a massive synthesizer capable of producing incredibly thick, dense tones with up to six note polyphony.

The hardware side of things is at once simple and ingenious. Buttons on the consoles are connected together for remote control using ribbon cables and transistors. System clocks for the consoles are provided by a LTC1799 oscillator chip, which allows the clock to be modulated for audio effects. Initial tests with up to six Gameboys running from a single clock source have been remarkably successful.

Any mad scientist could see the genius involved in this project, and we can’t wait to see the full rig in operation. If you’re just getting started with Gameboy music, check out this primer on modding your Gameboy for hi-fi sound. Video after the break.

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MIPI CSI-2 Implementation In FPGAs

November 29, 2018 by 31 Comments

[Adam Taylor] always has interesting FPGA posts and his latest is no exception. He wanted to use a Zynq for image processing. Makes sense. You can do the high-speed parallel parts in the FPGA fabric and do higher-level processing on the built-in CPU. The problem is, of course, you need to get the video data into the system. [Adam] elected to use the Mobile Industry Processor Interface (MIPI) Camera Serial Interface Issue 2 (CSI-2).

This high-speed serial interface is optimized for data flowing in one direction. The camera, or the master, sends a number of bits (at least one) serially with one clock. To increase speed, data transfers on both rising and falling clock edges. The slave also has a pretty standard I2C master to send commands to the camera which, for the purposes of I2C, is the slave.

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Adopting An Orphaned Ultralight

November 29, 2018 by 69 Comments

Owning and flying your own small airplane offers a nearly unmatched level of freedom and autonomy. Traveling “as the crow flies” without having to deal with traffic on the ground immediately shrinks your world, and makes possible all sorts of trips and adventures. Unfortunately the crippling downsides of plane ownership (storage and maintenance costs, knowledge that you might die in a fiery crash, etc), keeps most of us planted squarely on terra firma.

But not [ITman496]. His dream of owning an ultralight has recently come true, and he’s decided to share his experience with the world. He’s got a long way to go before he slips the surly bonds of Earth, but there’s no better place to start than the beginning. In a recent blog post he documents the process of getting his new toy home, and details some of the work he plans on doing to get it airworthy.

The plane in question is a Mini-MAX that [ITman496] has determined is not only older than he is, but has never flown. It was built by a retired aircraft mechanic who unfortunately had problems with his heart towards the end of assembly. He wisely decided that he should find a safer way to spend his free time than performing solo flights in an experimental aircraft, so he put the plane up for sale.

After a considerable adventure transporting the plane back home, [ITman496] found it was stored in such good condition that the engine started right up. But that doesn’t mean it’s ready for takeoff by any stretch of the imagination. For his own safety, he’s planning on tearing down the entire plane to make sure everything is in good shape and assembled correctly; so at least he’ll only have himself to blame if anything happens when he’s in the air.

One the plane’s structure is sound, he’ll move on to some much needed engine modifications including a way to adjust the air-fuel mixture from inside the cockpit, improvements to the cooling system, and installation of a exhaust system that’s actually intended for the two-stroke engine he has. When that’s done, [ITman496] is going to move onto the real fun stuff: creating his own “glass cockpit”.

For Hackaday readers who don’t spend their time playing make believe in flight simulators, a “glass cockpit” is a general term for using digital displays rather than analog gauges in a vehicle. [ITman496] has already bought two daylight-readable 10.1″ IPS displays which he plans on driving over HDMI with the Raspberry Pi. No word on what his software setup and sensor array will look like, but we’re eager to hear more as the project progresses.

If you’re not lucky enough to find a mostly-complete kit plane nearby on Craigslist, you could always just make your own airplane out of sheets of foam.