Learn JTAG By Writing A Bit-banging Programmer

August 31, 2013 by Mike Szczys 17 Comments

j-tag-flow-chart

[Pesco] won one of Dangerous Prototypes’ PCB giveaways a few months ago. He opted for a CPLD breakout board. He just needed to put in a parts order and populate the components himself. But then what? He needed a JTAG programmer to work with the chip. Like any good autodidact he choose to make his own rather than buying one. He absorbed the JTAG specification and coded a bit banging programmer using an Arduino.

We’ve used JTAG many times to program ARM chips. But until now we never took the time to figure out how the specification works. If you’ve got an IEEE subscription you can download the whitepaper, but [Pesco] was also able to find one floating around on the interwebs. The flow chart on the left is the cheat sheet he put together based on his readings. From there he wrote the Arduino sketch which implements the programming standard, allowing him to interact with a chip through a minicom terminal window.

[via Dangerous Prototypes]

Free Hackaday Stuff At Next Week’s Open Hardware Summit

August 30, 2013 by Mike Szczys 8 Comments

If you’re headed off to the Open Hardware Summit next week we’ve got some free swag for you. Readers paying any attention know that Hackaday was acquired by Supply Frame over the summer. There had been some nervousness in the comments about what this all means. But I think you’ll agree it’s a good sign that Supply Frame is one of the major sponsors of the event at the ‘FANATIC’ level.

Several of the Supply Frame guys will be attending (which makes me jealous since I want one of those ePaper display badges so badly!). Details haven’t quite firmed up yet, but we believe there will be a Supply Frame booth were you can stop by, chat, and see if they’ve got any Hackaday T-shirts left to hand out. I don’t think they’ll run out of stickers so you won’t go away empty handed.

Also ask them for a beta code for the hush-hush new online tool which they’ve been working on. I got a preview when I visited their headquarters in Pasadena last week. It’s something that EE and hobby electronics enthusiasts will appreciate as it simplifies the planning and part choosing process of a design. Actually, now that I think of it, it solves a problem I’ve heard [Dave Jones] rant about before on the Amp hour. Obviously I’m under a bit of an info embargo until they get the service fully online but I’m sure we’ll cover it once they do. Incidentally, one of the devs on this project — [Ben Delarre] — founded CircuitBee.

Our own [Eric Evenchick] will be on hand as well. He’s still networking for future employment so you might not find him just sitting at the SF booth. He will have Hackaday stickers to hand out as well since I felt bad about not sending swag along with him to Def Con. Look for his recollection of the event once it is all wrapped up.

Worry not if you can’t attend OHS. [Brian Benchoff] is planning a trip to World Maker Faire later in September and he’ll be packing a stash of freebies as well!

Cooling Fan Speed Controllers Do It By Generating Heat

August 30, 2013 by Mike Szczys 82 Comments

cooling-fan-speed-controllers

We’ve never torn one apart ourselves, but it boggles the mind just a little bit to learn that these cooling fan controllers generate heat to do their job. We’d bet we’ll get shouted down in the comments, but doesn’t this seem counter-productive?

At any rate, we enjoyed reading two posts on this topic. [Göran’s] first adventure with the hardware started when he was trying to design his own speed controller. He saw a reference design in the LM7805 linear regulator datasheet which allows the adjustment of the output by changing the ground reference. When fed with 12V this ends up putting off some heat but it is a simple and reliable solution. He was a bit surprised to crack open a Zalman module and find the exact same circuit inside.

The controller in the background is an eBay purchase. He cracked that one open as well (that’s the link at the top) and found a circuit with a linear regulator in it, but this time it was a TL431 adjustable regulator. So here are our questions: Which one of these two is better and why. And can you do it relatively inexpensively without generating as much heat?

[Ken Shirriff] Completely Reverse Engineers The 1974 Sinclair Scientific Calculator

August 30, 2013 by Mike Szczys 46 Comments

Wow. Seriously… Wow! The work [Ken Shirriff] put into reverse engineering the Sinclair Scientific is just amazing. He covers so much; the market forces that led [Clive Sinclair] to design the device with an under-powered chip, how the code actually fits in a minuscule amount of space, and an in-depth look at the silicon itself. Stop what you’re doing and read it right now!

This calculator shoe-horned itself into the market when the HP-35 was king at a sticker price of $395 (around $1800 in today’s money). The goal was to undercut them, a target that was reached with a $120 launch price. They managed this by using a Texas Instruments chip that had only three storage registers, paired with a ROM totaling 320 words. The calculator worked, but it was slow and inaccurate. Want to see how inaccurate? Included in the write-up is a browser-based simulator built from the reverse engineering work. Give it a try and let us know what you think.

Now [Ken] didn’t do all this work on his own. Scroll down to the bottom of his post to see the long list of contributors that helped bring this fantastic piece together. Thanks everyone!

[Thanks Ed]

PlayStation 3 Analog Audio Out Hack

August 30, 2013 by Mike Szczys 34 Comments

ps3-analog-audio-out

Here’s the scenario: You’ve got the rage to play som CoD (we’re more GTA fans but whatever) but the monitor you’re going to play on has no speakers. You can get a crystal clear image using HDMI, but getting sound is a different matter. What’s the fix? Crack open your PS3 and solder on some audio connectors.

[Paul] knew there is a special cable that breaks out analog audio. Like original Xbox hacking of ages past, there is now plenty of information online about the internals of these machines. He grabbed a copy of the A/V pinout and found the analog audio pins. After soldering on this pair of RCA cables he ~~cut~~ savaged a hole in the case and put the console back together. The machine he’s working with is a salvaged unit with no Blu-ray drive — he links to his past posts on the repair process. You may be thinking what good is it without an optical drive? Remember, this is the beginning of the Internet age… everything is downloadable.

Bluetooth Low Energy Weather Lamp

August 30, 2013 by Mike Szczys 6 Comments

bluetooth_low_energy_ble_weather_lamp

This is a well-executed proof of concept which [Aaron Jeromin] threw together in a couple of hours. This lamp hosts a Bluetooth Low Energy weather display. The project was a way for him to get used to using the BLE module. But to make the most out of that hardware this should really be refined into an actual low energy circuit. We do think the timing is perfect to feature this project since we just looked at a BLE primer yesterday.

He’s using a BLE Mini board from RedBearLab. It uses a Texas Instruments CC2540 SoC. We’d love to see a follow-up that does away with the Arduino in lieu of code running on the TI chip. But we would have done the same thing (use the uC we were most familiar with) when testing the BLE board out for the first time. It gets weather data from an iPhone. The forecast is projected as one of three icons using an LED bulb and a stencil which is positioned by a hobby servo.

Other inanimate objects that can tell you if it’s storming include this color-coded umbrella stand.

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24-hour Hackathon Produces Respectable Accelerometer Labyrinth

August 29, 2013 by Mike Szczys 12 Comments

hackathon-labyrinth

We’re not sure if this was some type of corporate team building, but if it was sign us up for the next one. [Filipp], [Saluka], and [Michael] participated in a recent 24-hour hackathon hosted by Microsoft. They whipped up this labyrinth game controlled by a Nexus 4 Android phone.

This thing looks so well crafted we’re shocked that it’s a 24-hour build. Just putting together the walls of a maze that size takes some time. They then mounted it in a gimbaled frame which tilts the using servos. Check out the demo video below to get a look at the underpinnings. There are several elastic bands connecting the base to the maze. These act as shock absorbers to help keep the movement smooth and to prevent any oscillations from the frame flexing. For us this is an important design element that we’ll keep in mind (just in case we need to win another competition by designing a labyrinth).

An Arduino controls the servos, using Bluetooth to communicate with the phone. The team mentions some filtering used to help make the user experience more natural but we didn’t see many details on this aspect of the hack.

Continue reading “24-hour Hackathon Produces Respectable Accelerometer Labyrinth” →