Pocobor.

Toyota iQ Car Generated Font

I normally don’t get too excited about fonts.  I’m pretty happy with Times New Roman – go ahead, make fun of me, I can take it.  However, I recently came across a new font that caught my attention.  It is a font made by recording the motions of a car as it “writes” out each letter at the hand of a stunt driver.  The project was carried out by Happiness Brussels, an innovative advertising group in Belgium that has effectively integrated technology into many of their projects.

Beyond being a very innovative way to advertise the handling of a new car (the Toyota iQ), the font development project illustrates a real-world example of an object tracking system. By mounting a camera to the ceiling of the warehouse and attaching colored circles to distinct portions of the car, the specialized software can track the overall position of the vehicle in real time.  Further, it can track the path of each tire as the vehicle moves through space and really adds to the authenticity of the font.  The project effectively conveys the interplay between the physical world and electronics/software.

Check out more here.

Design to the People

The MICROFACTORY MOW

I came across a cool post about the MICROFACTORY MOW by DaeKyung Ahn on Core77 yesterday that really got me excited. DK’s MOW is an in-home manufacturing machine to produce products from scrap flat stock you may have lying around your house, like the brown cardboard/corrugate that lies around after the purchase of any new product. The concept relies on a community open source web-portal where users freely share/upload their custom product ideas so others can search and download the plans to their personal machine for home machining. Although it wasn’t clear to me how the machine instructions would be translated from the ideas, I can easily imagine a simple sketch pad interface on the website to translate a pattern to control code that users with basic geometry skills could master.

microfactory_body

MOW In Action

I am really excited about empowering everyday people to explore design in their own homes with simple manufacturing tools and by utilizing waste material. (Brian discussed this in his Democratization of Design post back in January related specifically to the RepRap machine.) So many people have amazing ideas that remain dormant because they don’t have access to the tools or don’t realize how easy it can be to prototype those ideas – maybe MOW can help bridge that gap. And the open source web-portal provides an extremely low barrier to entry; you can try out existing proven designs before experimenting on your own. Or maybe you just want to turn your garbage, bound for a landfill, into something valuable.

The video captures the iterative design process and a demo of the finished prototype. Check it out:

Hand Soldering – Part 2

Quad Flat No-Lead Chip

This post builds on my previous post, which discussed hand soldering surface mount passives and QFP chips. As I mentioned last time, these are vital skills for any circuit board designer – the ability to modify or rework a board is integral to a time-effective development process.

Today I’m going to talk a little about hand soldering QFN chips – these chips are extremely small, which can be very useful for tiny, densely packed boards but makes them a little difficult to work with by hand. As a reminder, these posts are building on some excellent tutorials created by Curious Inventor. The relevant information for QFN chips can be found here.

Quad Flat No-lead (QFN) chips are like QFP chips but don’t have leads extending beyond the sides of the chip; instead, they have pads on the bottom of the chip. For these types of chips, however, my experience diverges from the Curious Inventor tutorial a bit. Their method certainly works but I have found it easier and more effective to use solder paste with the hot-air station as opposed to tinning the pads with actual solder. In terms of equipment, you will need good tweezers, a hot air source (either hot air gun or dedicated soldering rework station), solder paste and solder flux.

The technique that we have found works best involves the following steps:

  1. Clean the chip and circuit board pads and make sure that the chip can lie flush on the board.
  2. Apply solder paste on all of the circuit board pads using an applicator syringe (below). Make sure there is paste on all pads but use sparingly – too much could lead to shorts.
  3. solderpaste

    Solder Paste

  4. Place the chip in the correct position on the board using tweezers. The solder paste may make it difficult to see if the chip is correctly aligned with the pads but use silkscreen markings on the PCB to index the chip’s location. Fortunately, surface tension effects with the large center pad will help the chip self-align as long as it is close to being in the correct position. Make sure that the chip is firmly pressed down on the board and is flush or as close as possible to it.
  5. Preheat the chip and board using the hot air gun to about 200 degrees Fahrenheit. Depending on your setup, this can be accomplished by varying the heat and flow rate of the gun or changing the distance between the chip and the hot air nozzle. The chip should remain in place without fixturing as long as the board is horizontal and the hot air is coming orthogonally from above.
  6. Turn up the heat to about 350 or 400 degrees. Once you see the solder melt, continue applying heat for up to 15 seconds more. You want to be sure that the solder has fully melted and reflowed to all of the pads but too long and you can overheat and break the chip and / or board.
  7. There will probably be excess solder along the sides of the chip. Apply flux and use a soldering iron and wick to remove this solder. Try to remove all accessible solder, not just visible accumulations.
  8. Verify that no shorts are visible with a loupe or microscope. Professional shops sometimes use x-rays to check underneath the chip and if this kind of equipment is available, it can be very helpful. However, in our experience it is not necessary.

qfn2

QFN chip mounted on a PCB

I’d love to hear what works (or doesn’t) for others so feel free to add your two cents in the comments.

Happy Soldering!