New Arduino user/builder here. Been tinkering with electronics and robots for years. I needed a new hobby, so I picked up an Arduino UNO from Radio Shack.
While I'm waiting for the rest of my parts to show up, I wanted to say "hi" and ask a question or two.
For power, I will have separate batteries for the motors and UNO board. I plan on a 9V "snap top" battery for the UNO wired in through the power jack. The motors will run of a AA pack of 4 or 5 batteries. Maybe a NiCad R/C car-type battery.
Is the 9V ok for the UNO? At the moment, my sensors will be an ultrasonic rangefinder, two IR distance detectors, and two photo resistors. Will also have a motor shield attached to it.
If I remember to take pictures, will attempt a write up of what I do. From a small platform, I hope to eventually build a bigger version, like kitchen garbage can size robot. Hey, that is a good idea! Trash can that can take itself out!
9V battery is OK. Just remember to unplug the battery when the USB is plugged in. For my robot I use a 12 volt NiCad pack from an old drill and have a 7805 from that to power my rangefinders and other peripherals. So the 9v powers only the Arduino.
9v battery snap-top is ok, but has limited energy, and won't power the Arduino for v
ery long - maybe 10 hours or so. I typically use sets of NiMH AA-cells in my robots.
Once I get the chassis (DFRobot 2WD) and put everything together, ifnthere is enough room and motor power I'll probably go for another pack of AA's for board power. But I would need at least a 5 or 6 pack of AA for the UNO, correct? 7V is the "sweet spot" it seems for power.
I have a few NiCd packs from my R/C Mini-T that should fit the bill.
6 NiMH AA-cells will give you nominal 7.2V, which is perfect for the Arduino, and also in
terms of being reusable batteries rather than throwaway. I just get the ones from Walmart
and Target, as these are not super high-performance racing vehicles. A 6-cell NiCad pack
would also work, although their energy ratings are more like 600-mAh, while NiMH are
2000-2500 mAh.
For the DFRobot 2WD, initially I might try using just a single 6-cell NiMH pack for both
motors and Arduino, as the current reqs are not high for the motors. I would however,
wire extra caps at the point where the battery connects to the motor diver and Arduino
board. See Main Cap section, http://www.4qdtec.com/pwm-01.html#cap
I have a separate supply for the Arduino because I can't have the USB and the plug in to Vin at the same time. That way if I want to test the robot I can use the USB serial port for debugging and Arduino power with power from the 7805 for peripherals.
Be aware that 7.0 volts is the minimum input to the onboard regulator thru the plug (6.3 to Vin) because of the reverse polarity protection diode.
The DFRobot platform was better than I expected. I thought it was going to be plastic, but it was a well-machined piece of metal.
They included a 5-cell AA holder, which was nice. Wired that to the included power switch for running the motors.
The holes where you mount the Arduino board (on top plate, I assume), don't quite line up. I could only get three posts to line up, and then I could only actually screw in two of them.
Not that much room left for my breadboard, unless I cover the servo hole. Which I don't want to.
Need to figure out a way / a thing to mount my ultrasound rangefinder on to.
Now I am working on the fun part, programming!
I took pictures along the way to document. Actually, I forgot to take a few pictures I was so excited. So I un-assembled, took pictures, and re-assembled the robot.
But the coolest part of this project so far is getting my young son and daughter involved. Daughter is way young, just wants to "see the robot go", but my son helped put many of the parts together.
