CNC-PBDU (pancake batter dispenser unit)

Flapjacks taste infinitely better when they’re machine-made. Well, that’s true for [Mexican Viking] who built an automatic pancake maker to the delight of his family.

Obviously, the building material of choice is Lego. The machine consists of a base with two linear gears on either side. A gantry is held high above this base, travelling upon geared towers to either side. The writing nozzle, fashioned out of ketchup bottles, can move back and forth along this gantry for a full range of motion along the X and Y axes. Lego pneumatic pumps supply pressurized air which forces the batter out of the bottle reservoir. This dispensing system is extremely clever and worth reading a bit more about. But if you just want us to make with the good stuff, you can see it grilling up pancakes in the video after the break.

The only thing missing is automatic flipping.

[Read more...]

Reworking Ball Grid Array circuit board components at home

[Jack Gassett] is developing a new breakout board for an FPGA. The chip comes in a ball grid array (BGA) package which is notoriously difficult to solder reliably. Since he’s still in development, the test boards are being assembled in his basement. Of the first lot of four boards, only one is functional. So he’s setting out to rework the bad boards and we came along for the ride.

To reflow the surface mount components he picked up a cheap pancake griddle. The first thing [Jack] does is to heat up the board for about two minutes, then pluck off the FPGA and the FTDI chips using a vacuum tweezers. Next, the board gets a good cleaning with the help of a flux pen, some solder wick, and a regular soldering iron. Once clean, he hits the pads with solder paste from a syringe and begins the soldering process. BGA packages and the solder paste itself usually have manufacturer recommended time and temperature guidelines. [Jack] is following these profiles using the griddle’s temperature controller knob and the timer on an Android phone. In the video after the break you can see that he adjusts the timing based on gut reaction to what is going on with the solder. After cleaning up some solder bridges on the FTDI chip he tested it again and it works!

[Read more...]

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