Introduction: Autonomous Hovercraft
This is a project I did for a high school engineering project. I had some of the stuff laying around, so it only cost about $200. I have experience using the Parallax BS2 (Basic Stamp 2), and had a spare board laying around. This is all after i finished. I had not planned on making this an instructable, but figured, what the heck!
Step 1: Materials
HB-25 motor controller (x3) ((Any motor controller that can accept a servo pulse should work))
IR-sensor pair (x2)
Hitec HS-322HD servo
EDF-50 style ducted fan (x3)
Foam Board roughly 13" by 9" (x2)
battery pack 7.2 volt
Optional 6v battery pack for microcontroller
first five from Parallax.com
servo lying around
fans from local hobby store
7.2 v Ni-Mh from hobby store
battery pack harness from Hobby store
forgot to add switch to mine...
Step 2: Collect Materials/test
i collected my materials, from around my classroom, my room, orders, and the hobby store. The first thing i did was a check of the BS2 board to make sure it could run the HB-25's. Then i thrust tested my fans to find the two with similar thrust as my lift fans, and my stronger fan as my steering fan. The last test step was to do a sensor test with the servo. I assume you know that the motor controllers, and the micro controller/board are completely personal preference... i have experience with the BS2, so chose it. I am sure an arduino would work just fine...
Step 3: Construction
I layed out my components and attempted to balance the masses of each around the board, and mounted. the BS2 board (with module) was located on the front, with the IR sensors and the gyro connected to the internal breadboard. Then I cut the foam board to size, and cut out holes for the trust fans. i also cut the top, and the foam out for the servo to drop in. The servo moves the pusher fan through ~180 degrees for steering, and the fan can reverse. i mounted everything, and checked my balance. Fixed the balance problem, and found i needed the base up, so cut a rectangle of foam board to act as a "pseudo" skirt, because i do not believe the fans pushed enough air to inflate it. If you have more powerful fans, a lighter set up, or just want to try a skirt, please let me know if it works/raises the platform more than an eight of an inch off the ground...
i DO not know what happened to the image notes on this page... but it is the EXACT same image as the first page.
Step 4: Programming
The final step before final testing is... PROGRAMMING! I took my inputs (gyro and IR) and figured out how they could work in a large if...then statement, and coded it. The gyro has not been reading properly, so it likes to spin... the gyro is to counteract the spin by telling the servo to turn the fan against the spin. The IR system is object detection/avoidance. It is set so that if it "sees" an object it will move away/back up. The reverse is not perfect... need to check the code on that.
The next step is loud, and high pitched... turn your speakers way way down. and make sure your cat is out of the room.
i do not have the program on this computer... i do not know why... and the image is too small in my window for me to put any real notes on it... sorry!
Step 5: VIDEO!!!! Turn Down Your Speakers...
Step 6: Reasoning
I have separate power systems so that if the motors suddenly call for a surge, the micro controller will not reset from power loss. The micro controller is powered by four AA batteries, which also power the steering servo. The fans and the HB-25's are powered by the Ni-Mh pack, which only allows for a few minutes of "flight", but it is plenty for my uses. With the current set up, i have limited to no spare lift, but larger, more powerful fans could easily give at least a few pound/kilos of lifting capability, and the HB-25's have a voltage range up to 12/13 ish... the fans are only 7.2v. and i have them running at factory voltages.
same as step four... sorry!