What’s The Point?

March 2012
By Bryan Bergeron

I just purchased a pair of those R/C mini-helicopters for about $20 each. Consider that even if I could design such a craft, the parts for a remote control, battery recharging circuit, and radio receiver would cost more than $20. The helicopter body, servo motors, gyroscope, and gears would probably cost another $200, assuming I could find the parts and the plans to build the helicopter.

This reality is both cause for celebration and potential depression. On one hand, robotics has never been as affordable for the roboticist. If you’re looking for raw materials for your project, it’s simple enough to buy a fully functional device and strip it for parts. Stripping one of those helicopters yielded dozens of small parts that I couldn’t have located — much less made on my own. (Perhaps I could have made a few of the parts if I had one of those 3D printers.)

On the other hand, what’s the point of scuttling a perfectly good R/C craft? After all, why not just use the craft as a platform and try to attach a micro-camera? That’s a reasonable approach, and one that would allow you to focus on, say image recognition, as opposed to getting a micro-camera up in the air.

However, avoiding platform development is probably shortsighted. There’s a lot to be learned from building your own robotics platform. Even if your creation is heavier, bulkier, more expensive, and less maneuverable than what’s commercially available, there is the fringe benefit of learning how to engineer a platform on your own. That might translate to frequent crashes, delays, and some degree of frustration. However, in the long term, you’ll know not only how to flip a power switch, but how to repair, upgrade, and modify your creation.

I’m not suggesting you ignore all of the great bargains out there. Instead, leverage what you can get your hands on by performing nondestructive teardowns. Working incrementally, disassemble and then reassemble the device. For example, if you have one of those minihelicopters, start with the rear rotor. How is it wired? How large and how powerful is the motor? Are the blades fitted directly on the motor or through gears?

Next, examine the power supply. Use your DMM and a power resistor to determine the voltage and milliamphour rating of the Lithium battery. How is the voltage regulated during flight? Is there anything on board to protect the battery against overcharging? What can you learn from the charging station? What safety circuitry or physical barriers are in place to prevent overcharging or reversing the polarity of the charge? In short, what are the takeaway lessons that you can apply to your own designs?

Everyone loves a bargain. There is no rule that says you can’t enjoy a few toys while you’re experimenting with robotics. If you want to get a real feel for what it takes to create a robot however, you have to take out your tools, bag of parts, schematics, and get to work. After all, robotics is about the journey. SV

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