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Arduino Survival Guide: Workbench Edition

Pullup Voltage Divider

Pullup Voltage Divider

Herewith, the slides for the talk + lab session I’m doing today for Squidwrench:

Arduino Survival Guide – Workbench Edition

Unlike most Arduino courses, I assume you’re already OK with the programming, but are getting tired of replacing dead Arduinos and want to know how to keep them alive. The course description says it all:

Learn how to help your Arduino survive its encounter with your project, then live long and prosper. Discover why feeding it the proper voltages, currents, and loads ensures maximum Arduino Love!

Ed will describe some fundamental electronic concepts, guide you at the workbench while you make vital measurements, then show you how to calculate power dissipation, load current, and more. You’ll understand why Arduinos get hot, what kills output bits, and how you can finally stop buying replacements.

Among other lab exercises, we’ll measure the value of the ATmega’s internal pullup resistors, which everybody assumes are 20 kΩ, but probably aren’t. Hint: you can apply Ohm’s Law twice to that simple circuit and come up with the right answer, but only if you’ve measured the actual VCC voltage on the board.

The Mighty Thor will detail how to not prepare Fried Raspberry Pi.

In the unlikely event you’re in Highland NY, stop by: you’re bound to learn something.

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  1. #1 by hexley ball on 2013-06-15 - 15:34

    Nice set of slides. One small note — when measuring the effective value of the pullup resistor one really wants a reasonably good multimeter. If one of your students uses a $10 analog meter from the auto parts store with a 2K ohms/volt sensitivity to measure the voltage across the 47K load resistor, well, his or her mileage will definitely vary due to the meter’s input current.

    But then I guess that would fall under the heading of A Teachable Moment :-)

    • #2 by Ed on 2013-06-15 - 15:45

      a $10 analog meter from the auto parts store with a 2K ohms/volt sensitivity

      They’re now $15 and this “analog” thing of which you speak, I know not what you mean. [grin]

      But you’re right: much to my astonishment, one can still buy analog meters. I’ll say “Digital multimeter” in the pre-reqs. Good catch… thanks!

      We actually pulled off that measurement this morning: 47 k on one chip, 43 k on another. I love it when a plan comes together!

      The Teachable Moment was discovering that some wall warts have negative center pins…

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