My wife doesn’t like it that I call this robot Barbie, but I just can’t help myself. Looking at the pan and tilt tower with video and ultrasonic sensor, it looks like the robotic version of a naked Barbie Doll. So it’s name is Barbie.
Barbie started as a DFRobot 4WD platform kit. The platform was very complete, right down to providing a power switch and charging jack, motor wire and prebuilt DC Motor and gearbox combinations. It didn’t provide a battery tray and I actually appreciated that. I planned to run it off a NiMH pack that carried a little more oompf than a few alkaline batteries. I added a pan and tilt bracket and a pair of regular sized hobby servos, and added an ultrasonic range finder, and infrared reflecting ranger and hot spot locator.
Barbie viewed from the side
It’s powered by an Arduino coupled with an Adafruit Mshield. The Mshield is my absolute favorite controller shield. It will operate 4 DC motors and 2 servos. It will also operate 2 stepper motors and 2 servos. I directly power the motor shield with the NiMH pack and operate the Arduino with a standard 9v battery. This provides about 3 hours of robot use.
It has two main parts; the chassis which is a fully closed box inside which the drive systems and battery goes. The other part is the deck. The arduino us mounted to the chassis under the deck. It has a central position keeping wire runs shorter. On the deck is mounted the pan and tilt tree and the 9v battery is clipped to the bottom of it in the rear. I mounted the deck with parts from a Gilbert Erector Set. They were just the right size to amply hold the deck, but raise it higher by an inch than stock.
I use a regular DC charger wall wart that was mated to the battery in its earlier life in an R/C car. I put a standard male power plug on the charger so it jacks right into the batteries. There is a switch to disconnect the Mshield during the charging period. It also helps when tuning the robot. With the switch off, the servos and arduino will work but the motors are stopped. This allows focus on the servos as I tuned them for turn rate and angle.
It still needs tuning. It operates autonomously well enough except for an occasional glitch that causes it to rush the wall, crash, and then execute its avoidance move. Oops.
For a wheeled robot I
Barbie viewed straight on
like it. I especially enjoyed how complete the kit was. It makes up for there not being any instructions anywhere on assembling the DFRobot kit. However, it didn’t take but a couple of minutes to figure it all out. It was funny though; I went to their website and was able to see some clear photos of the assembled kit. But the entire site was in Chinese and so there was no way to read anything at all. But as I said, I succeeded.
It’s programmed in Arduese, at least that’s what I call it. It seems to be a combination of a number of programming languages like Basic, C, C#, Perl, and PHP. But I’m getting a handle on it and there is a lot of support on the various robot sites if you register. So far I have made two robots which operate autonomously –choosing their own destiny and doing a pretty good job. Once I find the glitch in Barbie, I’ll be able to send her and MyBot out for an afternoon patrol. You never know…