Curious Inventor Blog

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How Legos are Made

If you haven’t checked out Gizmodo’s videos from inside the lego factory, here’s another encouraging link. They also have video of the shelving system robots that automatically store and retrieve legos from over 65 square miles of equivalent storage space. A couple more Lego fun facts:

  • The tolerance on the bricks is less than .00008 in. Human hair varies between .001 and .01 in.
  • Only 18 / 1 million pieces fail inspection, according to this HowStuffWorks article.
  • Lego now makes some 19 billion bricks a year.

 

Homemade Solder Paste Stencils

All sorts of people are using toaster ovens and skillets to reflow (melt) solder paste on PCBs, but one bottle neck is applying paste to the pads. Using a syringe takes a long time, and getting custom made stencils is fairly expensive. tymm posted a cool instructable showing how to roll your own solder paste stencils. He uses the same process for etching your own circuit boards but does it on a thin piece of copper bought from a hardware store.

home made solder paste stencil

Robotic Ball Controlled by Music

Motors inside the ball work against a counterweight to allow it to move without external wheels. I believe certain pitches and sequences control how it moves. It can also play music itself–a piezo actuator uses the entire outer shell as a speaker to play back manipulated portions of what it hears. From a Robotics and Art conference that was taking place near RoboCup 06.

Screwdriver substitute for lost chuck key

Stick a screwdriver or hex wrench into one of the chuck key holes. Then use it as a fulcrum with a regular / flat screw driver to tighten or loosen the chuck. There’s probably a good chance this could harm your chuck if you do this regularly, but you need that hole NOW–new chucks can come later.

 

poor man’s clamp

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.
double_sided_tape

poor man’s surface mount prototyping

Don’t want to send out for a PCB when you just have a couple surface mount parts that need prototyping? Make your own surface mount PCB. Dremel a copper-clad board into regions, cover them with solder, and then drop in components. You could only add solder under the exact component locations, but shellacking the whole board is more fun and gives you more flexibility.
closeup_done

  • First, sketch a quick diagram showing component locations and connected regions–the regions will be nodes in your circuit.

layout

  • Next, transfer lines over to the copper with a sharpie and lightly dremel off the top copper layer.

dremel

  • Brush on some flux. If you use a thick enough solder, it may contain enough flux in the core already.

apply_flux

  • Now coat the regions with solder. The higher wattage the iron, the better, since you’re essentially soldering to a giant heat sink. A 30W will do the job, but it’ll take a while.

spreading

  • Add components:

overview