Partlist Wednesday: LEDs

Every Wednesday we highlight a component from the updated partlist. This week: LEDs.

Surface mount LEDs feel a bit smaller than capacitors and resistors in the same package. Despite moving to 0603 C and Rs, we still use 0805 LEDs. It’s not just because we’re stuck with a reel of them, we find 0603 LEDs to be more difficult to work with.

As a rule of thumb on a quick prototype we use a 2K resistor with SMD LEDs at 3.3volts, and 4.7K or 10K at 5.0volts. Both are common values we have in bulk. The exact current at those values depends on the exact LED, but usually that’s less then 1mA.

Also on the partlist are two through-hole infrared LEDs. One is fairly narrow (25degrees) one is a little wider (50degrees). Both have a operating current of 100mA, and a pulse up to 1A.

Lots going on behind the scenes today, so the partlist post had to be short. What are your thoughts on LEDs?

MakerBot sends Colbert into space

MakerBot sends Colbert into space:

After scanning Stephen Colbert‘s head in preparation for Bre’s appearance on the Colbert Report, we encouraged Thingiverse users to mashup the Colbert model with all sorts of other objects. (And got to work ourselves.)

Not content to confine ourselves to mashups, we initiated the MakerBot Space Program with a mission to send a bust of Stephen Colbert into space on a weather balloon with a Flipcam and a GPS enabled cell phone.

Check out the video after the break. Continue reading “MakerBot sends Colbert into space”

TI deals: EZChrono at $24.50 only

octal apparently followed up on our TI Deals discount site post and ordered this Chronos wireless watch for half off! He writes:

Leave it to Texas Instruments to bring you the coolest development platform that harnesses the wireless capabilities of the CC430F6137 microcontroller. The eZ430 – Chronos development tool is all of that and MORE. Not only does it utilize the ultra-low power advantages of an MSP430 microcontroller, but also features a fully integrated sub-1GHz wireless transceiver in the same chip.

Building a classic Mac hardware clone

Build a Classic Mac clone, a plan for everything but the disk drives:

The classic Mac hardware clone seems almost doable, except for the floppy drive. Without a working floppy drive (or equivalent), the Mac clone would do nothing but boot up to the screen showing a disk with a question mark (remember that one?), or the “sad Mac” screen. If there’s no floppy, then there’s no Mac clone, end of story. But there’s also no simple way I can see to build and test a Mac clone floppy subsystem in isolation, without all the rest of the pieces present first. It appears that the only realistic path is to build everything at once, and hope the floppy problem can be solved, otherwise the rest of it will be useless. That’s not very appealing.

Dockstar debricking – JTAG with Bus Pirate

RedoX documented his Dockstar debricking with the Bus Pirate:

I recently bricked my Seagate Dockstar, so I had to use JTAG to restore it…
At the time, I didn’t have any JTAG adapter. I tried with a parport Wiggler, but without the correct chip it didn’t work. So I bought a Bus Pirate. And so, here’s the story of the Dockstar…

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

Free PCB coupon to RT #1 & #12 @dangerousproto

Every Tuesday we give away some extra PCBs via Twitter. This post was announced on twitter. The #1 and #12 person to retweet it get free PCBs. Thanks for the heads-up on auto-retweeters JT!

This week we’re giving away two PCB codes. Pick your own PCB from the free PCB drawer.

Don’t forget there’s free PCBs three times a every week:

  • Free PCB Sunday. The classic. Every week, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs while you wait for the weekend

There’s an extra Cygni ARM dev-board from Teho labs in the free PCB drawer this week.

Continue reading “Free PCB coupon to RT #1 & #12 @dangerousproto”

Enough Already: an Arduino based audio-b-gone for TV

Matt Richardson over at MAKE presents this cool solution to listening to the audio portion of the garbage overload known as entertainment news. He has design this project known as Enough Already which mutes the audio portion of a TV program when certain words are mentioned.

The hardware consists of an Arduino and the Video Experimenter Shield which reads the closed caption data from the NTSC video signal and sends the Mute command to the TV via an IR LED. You can download the Arduino sketch from this Makezine Google code page. As written the program keeps the TV muted for 30 seconds when one of the programmed trigger words (‘PALIN”, “TRUMP”, “KARDASHIAN”, “JEFFS”) appears in the caption data string. You can modify the code to include your own words, change the duration of the mute, etc. You could even modify it only unmute when certain words were used.

Novel technology allows LCDs to recycle energy


The idea that LEDs can act as light detectors as well as emitters is well known. Now researchers at UCLA are looking at LCDs with an eye toward using them to produce electric energy in addition to functioning as your smartphone display.

The UCLA engineers have created a novel concept for harvesting and recycling energy for electronic devices — one that involves equipping these devices’ LCD screens with built-in photovoltaic polarizers, allowing them to convert ambient light, sunlight and their own backlight into electricity.

The UCLA Engineering team created a new type of energy-harvesting polarizer for LCDs called a polarizing organic photovoltaic, which can potentially boost the function of an LCD by working simultaneously as a polarizer, a photovoltaic device and an ambient light or sunlight photovoltaic panel.

Via PhysOrg.

KiCad open source PCB layout package reviewed

T Boyd wrote a review of the open source schematic and PCB layout program KiCad:

That makes the third PCB CAD package I’ve spent hours getting to know a bit about. And I like it, at 8/11. Looks like the hours I spent trying to learn the other two were partly wasted.It is early days yet… maybe I will find something in KiCad that I can’t live with… but I suspect I won’t.

Via the comments.

Accurate milliohm measurement

Kerry writes:  I have just completed a project for accurate milliohm range resistance measurements. The details are on my blog .  I’d love to share this with your readers.

To effectively measure small resistance values in the milliohm range, we need to accurately measure the current flowing through and at the same time accurately capture the minute voltage drop across the terminals.

To accurately measure small voltages, one can use a programmable-gain precision instrumentation operational amplifier such as National Semiconductor‘s LMP8358. While you can use other op-amps with varies gains, one of the key benefits of using a programmable-gain gain precision instrumentation op-amp is that there is no need to match the gain setting resistors. LMP8358′s gain can be programmatically set to 10, 20, 50, 100, 200, 500 and 1000, which is superb for amplifing the millivolts voltage drop.

Thanks Kerry! Via the contact form.

Dangerous Prototypes hackerspace passport stamp

Dangerous Prototypes has a stamp for your hackerspace passport. To get a ‘visa’, find us at the Open Hardware Summit, Maker Faire, or your local hackerspace.

We studied several actual passport stamps when making the design. It has a few official boxes to tick with a (different-colored) ink pen, ostensibly the continent of the meeting. The @ line on the side is to indicate the location or event. Original Illustrator files are in the art folder of the SVN repository.

Making a stamp was cheap and easy. We exported Illustrator artwork to a high-resolution .PNG image, and sent it to an online stamp maker. The boxes on the HSPP are not the same size, but we found that 1.5×1.5inches is a good size that won’t encroach on neighboring stamps. Two laser-cut 1.5×1.5inch stamps cost $10 each. There’s a bunch of online stamp makers with about the same pricing, we used RubberStamps.NET because it’s next door to our Iowa office and shipping was super fast ($2 local, $6 worldwide).

Thanks to Tayken for design advise!

Samsung to launch banned tablet on Dutch market

Samsung to launch banned tablet on Dutch market:

South Korean electronics giant Samsung will Tuesday launch its Galaxy Tab 10.1 on the Dutch market in the midst of a legal stand-off with rival US-based Apple and sales banned elsewhere in Europe.

…

The case before the Dutch court is the latest episode in the battle between Samsung and Apple, manufacturer of the iPad, who have been pursuing legal action against one another since April over design rights.

…

A Dusseldorf court a week ago granted a separate injunction halting the sale of the Galaxy Tab 10.1 across Europe, with the exception of the Netherlands.

Silliness.

Fast forward from alpha – Agile Open Hardware Manufacturing

Here’s the summary for our breakout session with Eric from Seeed Studio. Come see us at the Open Hardware Summit next month:

Not everyone wants to etch PCBs and solder surface mount parts.  Manufacturing bridges the gap between hardware hackers and communities of firmware, software, and documentation developers who want to get involved. The production process can be treacherous however, and there’s lots of obstacles to success.

In this session, Eric Pan and Ian Lesnet discuss manufacturing for open hardware developers, covering four potential routes to production and the materials required. Attention is devoted to the barriers facing open hardware manufacturing. The session concludes with a proposal for a community-based open components library, to ease the process of turning ideas into tangible products.

Continue reading “Fast forward from alpha – Agile Open Hardware Manufacturing”

WIP – Bus Pirate milled case

fcobcn milled a Bus Pirate case:

I have been working over the week on this project.
It’s has taken a lot of time, mainly because I had to solve a lot of problems:

  • How to mill plastic; spindle speed, feed speed and cutting tool.
  • How to import the PCB design into a 3D CAD package in order to produce an accurate model.
  • How to generate the G-Code to use in EMC2.
  • And last, but not least, how to make it a good looking design.

More awesome DIY cases.

Via the forum.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

WIMM One – anywhere Android device

Wimm Labs has announced their development of the WIMM One platform, a go anywhere user programmable Android device. While their website doesn’t reveal the processor, they state the device will include a bi-modal display, capacitive touch screen, WiFi and Bluetooth, an accelerometer, magnetometer up to 32 GB memory and be housed in a water resistent 32×36×12.5mm case. The device will also include a 14-pin accessory connector.

According to their press release, they intend the device to be an open SDK/open hardware development platform.

Via iProgrammer.

DIY rover hacking with the Bus Pirate

hak8or is building a rover and posted pictures of DIY Bus Pirate:

Here is my bus pirate I am using for getting the contents of the EEPROM. I took the schematic from the original bus pirate, got rid of some stuff, changed some stuff, and made it a bit smaller. I should have used a SMD pic24f, but oh well. I mainly made it to break out a FT232 and practice making PCB’s and soldering. This was my first PCB I designed and soldered, and 0402 components were not THAT bad, just need a nice microscope. :P

Via the forum.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

XT-IDE adapter with CPLD builds

pietja built the XT-IDE controller with CPLD PCB, it will get further testing today.

“The XT-IDE project is a Vintage Computer forum driven project to develop and manufacturer an 8-bit ISA IDE controller. It allows any PC/XT class machine to use modern IDE hard drives or Compact Flash devices for long term storage.” (From the XTIDE project wiki)

Our version of the XTIDE controller replaces the 7400-series logic chips with a CPLD, a chip that can be programmed to replace dozens of individual logic chips. The logic is designed in software by drawing a schematic, and then uploaded to the CPLD. New logic circuits can be designed and tested without making new hardware each time.

If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.

PCB store survey results

Yesterday we asked how much you’d pay for a PCB from the PCB drawer. We played with the numbers and our findings are below. First, answers to some common questions.

Nothing will change with our weekly giveaways. We’d like to make boards available to people who want them, but don’t want to try to win one in a contest. We’ll still have free PCBs three times each week, and we’ll always send a free PCB to dedicated testers and developers. The unlimited PCB deal would be modified, purchased PCBs would not be eligible.

To start, we might stock 50-100 PCBs from the most popular projects. These would be proven designs, on 100% e-tested PCBs. You could buy draft/broken/prototype boards too, the kind we giveaway now, but our focus is on stocking specific boards such as the Bus Pirate.

Way more below the break.

Continue reading “PCB store survey results”

Simple Sunday circuit: variable voltage regulator

From time to time we’ll be posting shortcuts and hacks we use around the workshop that make a task easier and less expensive.

Here’s one example: a variable voltage regulator. We wanted to adjust the output from a 12 Volt solar cell to power projects needing lower voltages. The solution: construct a variable voltage regulator using an LM317, a fixed resistor and a potentiometer.

Continue reading “Simple Sunday circuit: variable voltage regulator”