First off, I realize that the Project 14 competition Simple Electronic Repairs has ended. Congratulations to all of the winners. However, I really want to repair my Mebo robot and I think it will be fun to document the process. So, I will start back at the beginning and tell you all about it.
What is Mebo?
Mebo is essentially a remote tele-presence robot. What I mean by that is you can do many of the things that you could do in a room if you were there, only from a distance whether it be a block away, a city away, or even across the globe. For instance, you can control the robot directly from an app on your smart phone. You can make Mebo maneuver around a room. There's a built in webcam, so you can see where Mebo is going and what's going on in front of him. There's a microphone so you can hear what's going on in the room. There's also a speaker so that you can speak to anyone that's in the room as well as make all sorts of weird and/or rude noises. Even better, Mebo has a robotic arm. You can pick up small items around the room and move them anywhere that's within Mebo's reach. This isn't an advertisement, but you can find out more about Mebo at http://meborobot.com/.
What happened to Mebo? How did he break?
The short answer is I don't know. I purchased the robot from a discount store in the US. Basically, the store buys returned merchandise from various retailers and puts it on their shelves. Most items are opened, damaged, missing parts, or otherwise unfit for putting back on the shelf. The store has a strict "no returns" policy so it's the ultimate buyer beware situation, but most things are deeply discounted. In this case, I saw Mebo sitting there and ended up walking out of the store with him for just 20% of his original retail price. A gamble, yes, but I figured I could make use of the platform and/or parts at the very least.
What's wrong with Mebo?
Once I made it home with Mebo, I pulled him out of the box, attached the wheels, inserted the battery, and turned on the power switch. And nothing happened. No lights, no sounds, no movement, no anything. I downloaded the app and tried connecting to Mebo over WiFi, but he wasn't there. He was essentially DOA. I checked the battery. It showed a full charge so at this point I know something has failed inside of Mebo. A short time later, I had my trusty screwdriver out and was removing all the screws from the undercarriage of Mebo. Once I removed the cover, I got a whiff of that peculiar but unmistakable odor ... of fried electronics. After removing both wheel assemblies and carefully labeling and removing all of the cable harnesses from the main board, I was able see the problem.
A switch mode regulator on the motor driver board had failed catastrophically. So, the only thing getting power was the H bridge motor driver chip which gets its power directly from the battery. Nothing else was powered.
To be continued...
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