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Off-The-Shelf Hacker: Raspberry Pi vs. Arduino

15 Jun 2019 6:00am, by

While talking with a guest right before this month’s Orlando Robotics And Maker Club meeting, the question of starting out with a Raspberry Pi or an Arduino came up.

As fate would have it, our club organizer had asked me if I could do a little show and tell since we didn’t have any formal presentations planned for the day. I usually carry a gadget-augmented tech talk with me to events about my Raspberry Pi and Arduino based steampunk conference badges, and it seemed like a great way to bridge the topic with this group. So that’s what I did.

Jerry, one of my robot club colleagues, who teaches physical computing, said he gets the same question all the time.

Why Two Kinds of Badges?

I started the robot club talk by explaining that I use two kinds of badges at a conference. The Arduino one is worn during an actual tech talk and the Raspberry Pi model is used when walking around the venue and show floor.

Both badges were shown to the audience as I walked to the front of the room.

I opened the talk by relating that the Arduino is made for speed and that it is so fast it can even pick up multiple contact events when pressing a push button. I then mentioned that the Arduino has a simple job… read inputs, do a few calculations and set outputs. The audience seemed interested and I dove into a quick side note of accounting for “switch bounce” in the firmware code.

The Arduino badge is simple and fairly light with a small square brass frame, an Arduino Nano and a three-color LED on a leather panel. A wide flexible plastic magnet is attached to the back of the leather panel with a matching flexible magnetic strip that goes under my shirt, holding the badge in place. There’s a thin two-conductor wire power cable connected to a 6-volt AA battery pack in my pocket.

Here’s a shot of the Arduino Nano badge:

Functionally, it runs a tiny Arduino program that fades through the red, green, and blue LEDs in a loop. I attached a clear decorative plastic “crystal” on top of the three-color LED for a little added glitz.

About three minutes in, I transitioned over to the Raspberry Pi-based badge. I plugged the badge into the projector and powered it up. Soon the familiar desktop appeared on the screen and I pointed out that the audience was looking at a full-blown Linux “chest-top” computer. It is a badge, after all. I used a tiny remote keyboard/mousepad during the presentation with the mini receiver plugged into a USB port. Although the chest-top has a touch screen, navigating around the desktop and clicking on things is much easier on a miniature mouse pad. I even pulled up a recent tech talk I gave at OSCON and flipped through a couple of slides. Always carry your miniature remote keyboard/mousepad with you.

The Gen 4 and Gen 5 badges side by side

Of course, the Pi badge has a Raspberry Pi 2 model B, a 3.5-inch color LCD touch screen, a handmade brass and leather frame, a digital thermometer, an accessory Arduino Nano attached to the ultrasonic sensor. The Nano sends data to the Pi over a serial line. The Pi can display distance measurements using an on-screen analog gauge written in the Processing programming language. I held the badge up and pointed out various parts as it was running the desktop and slides while still plugged into the HDMI cable.

Audience members certainly realized that the Pi-based badge was a radically different animal than the Arduino model.

Here’s this week’s clip of the two badges running side-by-side. The Pi has the promo video playing and the Arduino model has the “orbing crystal.”

And, yes, I shot the videos freehand, so there is some camera movement.

‘Show’ the Contrast

Contrasting differences with a real-world, hands-on demo is a great way to bring attention to something. The audience could readily see the Arduino badge softly orbing away on my lapel as I started LibreOffice and brought up my slides on the Pi badge. Audiences appreciate your expert running commentary as they see the gadgets actually working. Nobody is distracted by notes or slides. I recommend doing a physical demo over a straight slide show, whenever possible. Augment your stand-up demo “show” with appropriate slides, if you can weave them seamlessly into your program. You are the show, never the slides.

Speaking of the show. Back when I was in Toastmasters, we had a couple of hard chargers who blew through the first few skill levels in record time. At one meeting I brought up the importance of “the show” when speaking and they became instantly indignant. Speaking was serious business and shouldn’t be a… show. There was no convincing them. Very quickly, I drifted away from the discussion, just scratching my head.

Audiences want action. They want a little drama. They want some pizzazz and something that will hold their attention. They want something fun. Hardware demos are absolutely made for “the show” mindset. It lends itself to letting your imagination run wild and delivering a cool presentation that they’ll talk about with their friends when they get back home.

As off-the-shelf hackers, we should put on a good show. Everybody wins.

Catch Dr. Torq’s Off-The-Shelf Hacker column, each Saturday, only on The New Stack! Contact him directly for consulting, speaking appearances and commissioned projects at doc@drtorq.com or 407-718-3274.

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