The EEVblog is on a roll with interesting topics lately. In the latest episode [Dave] takes us through the nitty-gritty of switch mode power supply design. Using DC-DC converter IC’s in not especially hard. The datasheets tend to have fairly good usage schematics but there’s always a bit of heartache that goes into figuring out which external components will make for an optimal design. Get your calculator out and, in the video after the break, he’ll walk you through choosing component values based on the formulas for the MC34063 converter chip.
[Dave] makes the point that this is an extremely common chip, available from several manufacturers, and often found in consumer electronics. In fact, the switchmode supply hack from last month was using a regulator based around the MC34063. So you can buy it or scavenge for it. One thing to note though, we checked Mouser and Digikey and they’re pretty short on these chips right now. Plan your projects accordingly.
Continue reading “Building a power supply around a DC-DC converter”
[Ben’s] added some nice goodies to his Volvo in the form of an in-dash computer. The system monitors two pressure sensors for boost and vacuum, as well as reading RPM, O2, and exhaust directly. All of this is tied into the touch interface running on an eeePC 900A. But our favorite feature is that the system requires you to enter a PIN to start the ignition. The forum post linked above is short on details so we asked [Ben] if he could tell us more. Join us after the break for a demonstration video as well as [Ben’s] rundown on the system.
Continue reading “Car computer requires PIN for ignition”
Building an LED flashlight is simple, right? Take a battery, connect it to an LED by way of a resistor. Alright wise guy, now make one that steps up the voltage for multiple LEDs and don’t use a boost-converter IC to do so.
[fede.tft] shares a flashlight built inside of a used glue stick case. It’s the perfect size for one AA battery (we’re always on the lookout for good battery cases), and a shape that we’re familiar with as a flashlight. The problem is that he wants two white LEDs but with just one AA cell he’s never going to have more that 1.5V available. He licked that problem, getting to 7.2V by designing his own step-up converter using one transistor, an inductor, and three passive components. To get the inductor he needs, a stock part is disassembled and rewound to suit. Maybe you just end up with a flashlight when all is said and done, but then again, the Sistine Chapel is just some paintings on a ceiling.
[Steve] let us know about his MultiDisplay car monitoring system. Unlike traditional systems that rely on interfacing with the OBD-II protocol and existing car computer, the MultiDisplay uses an Arduino and custom shield with a combination of sensors; including temperatures, pressures, throttle, Boost, and etc. The data collected can then be displayed on a 20×4 LCD or streamed to a PC with visualization and event recording.
It’s nice to see half a years worth of work finally be complete and presented in such a clean and professional manner, keep up the good work [Steve]
Phasers come with two settings: stun and kill. [Luke] took this seriously when he put two Blu-ray lasers into a toy raygun. He picked up the toy from Amazon for about twenty bucks and set to work.
The laser diodes are both pulled out of a 6x BD-R burner, which we think is a pretty expensive source to scavenge from. [Luke] removed the toy circuitry, reusing the trigger, top switch, and battery pack. The two diodes are mounted on a swiveling carriage which is turned 180 degrees to switch between the two diodes. A boost driver converts the 3v from the batteries up to 7v for the diodes.
This is a skillful conversion and [Luke] should be proud. Don’t miss the video after the break and if you’re thirsty for more take a look at the last hand held laser we featured.
Continue reading “Laser raygun boasts 300mW, hunts Klingons”