Servo - May 2017

Any ideas on what my next steps should be?

Robert Gomez McAllen, TX

A. HUGE PROJECT, wow! I’ll barely scratch the surface here. The Stingray (Figure 7) is a beautiful and capable chassis; it’s a pity that Parallax stopped selling it.

The only problem IMO is that the gear motors are too fast in general, and WAY too fast for a telepresence robot. Any Wi-Fi video link will have nearly a second of lag, and you need to drive very slowly to avoid crashing.

I found some much slower 70

RPM motors for my Stingray on eBay for $10, which should be your first step. See my video at https://www. youtube.com/watch?v=cAbjISH5W S4 and search eBay for item

332053386842 or “DC Gear Motor 12V 70 RPM 37 mm High Torque 8 kg.cm.” You have so many choices for control and the video link. You can use a traditional RC control system with a wireless camera link. If you can live without sound, there are any number of $20 Wi-Fi drone cameras available to send video via Wi-Fi to a smartphone/tablet. (See my article on Wi-Fi cameras in the SERVO February

2016 issue.)

Full two-way comms is a lot more work and a subject of a book, not a magazine article.

I will close by mentioning Wowwee’s Rovio circa 2008 (Figure

8). Rovio was a full telepresence bot: Wi-Fi; two-way comms; Internet access; Northstar navigation;

Mecanum omni-directional wheels; auto recharging dock; you name it. It was WAY ahead of its time and under-appreciated. It set the bar very high.

You would do well to get one of those to study; they can be commonly found in mint condition on eBay for

$100. Quite frankly, it will probably do everything you need.

The main limitation is that software and firmware development stopped somewhere around 2010-12. There’s 32-bit Windows 7 software available at www.wowweezone .com/kb/ faq.php?id=75 and https://sourceforge. net/projects/ rovio/files. It’s certainly worth your while to track one down, even if you have to dig up a 32-bit computer to run it on. That’s a wrap for this month. Thanks for all your great questions. Keep ‘em coming to roboto@ servomagazine.com and let’s see what we can do. SV