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This sms-to-LED tutorial shows how to automate the manual button input on this $13 scrolling LED belt buckle with an arduino, and then how to pass SMS messages through it. A USB Host shield connects an android phone that passes SMS messages on. Full code is on the tutorial page.







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The Scanalog 2 is a great inexpensive tool for hobbyists looking to debug digital issues, especially if they can't afford an oscilloscope.  Debug SPI, I2C, Serial UART, 1-Wire, Maple Bus (more to come with software updates). You can even inspect that PWM or RC servo signal to make sure your arduino is outputting what you think it should.

Features:

• 20Msps on 4 channels
• 1.8V - 5V level detection
• 256k samples of storage on each line
• Playback on all 4 lines, or just 2 while reading from other 2

Wishlist:

• Better Triggering
• More flexible output--static pwm to control RC servos, for instance, or just for a clock generator.

 

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 Here's a quick video of drag soldering--a technique that enables you to quickly solder entire sides of ICs by simply dragging the iron across all the pins.  The key is starting with the right amount of solder, and adding generous flux.  The results are often better and more uniform than individual pin soldering. 

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A common mistake we've seen in our classes--as well as from experienced 'solderers'--is to clean the tip before putting the iron back in its stand.  This habit leaves the tip exposed to oxygen in the air which works quickly to oxidize (basically rusting) the end of the tip.  Almost all metals oxidize in air, and they do so much faster at higher temperatures.  When your tip is thoroughly oxidized, it will look burnt, and no solder will stick to it. And if solder won't stick to it, you won't be able to create a "heat bridge" of solder between the iron and part, and very little heat will transfer.

To avoid this, coat the tip with a large blob of solder every time before returning it to its stand.  While flux in the solder gradually eats away at the tip, oxidation will cause problems much faster. 

You may notice that new tips actually come coated with solder. We've seen manufacturer documentation recommending that you hold solder against a new tip the first time you heat it up so that the tip gets coated as soon as it's hot enough to melt solder.

Cleaning tip: If your tip is starting to look brown, and won't 'hold' solder, or the solder acts like water on a freshly waxed car, you can help restore it by repeatedly applying solder and wiping it off.  The flux in the solder acts like a cleaning against against the built up oxides.  It may take 20 or more cycles of this to get the tip back into shape.

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Here's an instructable showing how to Control a Hand Drill with an Arduino / roboduino to spool solder. This may not be on the top of everyone's project list, but a hand drill is strong enough to do a lot of tasks, so we hope this will be helpful to someone with another project idea,... maybe spooling guitar pickups.

Rather than use TRIACs to mess with the 120VAC, we found a servo was an easy and safe way to control the drill's trigger / throttle.  The setup also uses a home made optical encoder that triggers an interrupt in the arduino code.  The code is available here, and contains some useful bits like lookup-table speed control, state machine menu system, and interrupt based speed sensing.

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While SMT leds typically have a dot or small green line indicating their cathode, it can be hard to remember.  A quick way to test a LED is by touching the ends with a multimeter in 'Continuity Test' mode.  The multimeter generates a small voltage in order to detect a closed circuit, and this is enough to light the LED.  Although we couldn't burn out any LEDs with this Fluke, there's no guarantee your meter won't over-do the current, so we recommend doing just a quick touch, or putting a resistor in line.

 

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Inspired by Steve Chamberlin's post evaluating kicad vs eagle for someone new to both, here are some more opinions from the perspective of someone who uses both equally, (about 20 projects for both), but is certainly not an expert at either.

Summary: Eagle is more straightforward, has better library support of out of the box, and better community support (ladyada, sparkfun, etc.).

Kicad is free, and is maybe 1 or 2 revisions from being great.

Click the entry for our list of pros and cons:

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This video demonstrates how to solder a QFN or MLF chip without solder paste or stencils.  While solder paste and a stencil will product the most consistent results, this demonstration only uses an iron, flux, hot air and regular solder to get the job done.  

Future videos will demonstrate how to use a solder paste syringe, as well as the recommended method of using a stencil.

Equipment used in this video:

• Aoyue 6028 Hot Air SMD Rework Station
• Tweezers for Surface Mount Devices (SMDs)
• Alcohol Dispensing Pump Bottle
• Chipquik No-Clean Paste Flux Syringe
• Liquid Flux
• Flux / Alcohol Bottle
• Desoldering wick/braid
• .02 SAC (lead free) solder
• Horse Hair Brush (ESD safe when wet)
• Hakko 50W Soldering Station
• 10X Magnifying Loupe

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Inspired by the desks at atlanta's hackerspace, we made a new work station with a white board as a surface. For $12, you can get a 8x4 foot piece of panel board from Home Depot / Lowes. Read More

If breadboard jumper kits seem too expensive, you can easily make your own with 22 AWG solid core wire. Just strip off a half inch of insulation from the ends and you'll be able to make hundreds of jumpers for the price of a small spool. Read More

Tan Tran came up with a cheap substitute for aluminum standoffs: nylon tubing. Polyethylene does a decent job too, and can be had for under $.10 a foot at your local hardware store. The 1/4" OD (outside diameter) stuff shown in these pics accommodates up to #8 size screws.

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When soldering a lot of surface mount chips, or when you don't have a clamp handy, sometimes the best solution is just a piece or two of double-sided tape between the board and desk. "De-stick" the tape a little by touching it with your fingers to avoid permanent additions to your desk and to make it easier to rotate the board when needed. Only a small amount of tape is needed. Read More