Description: This UAV is intended mostly as an education platform to teach you the basics of microprocessors, embedded system programming and autopilot design. It will fly, but it's not designed to be a real production UAV. That said, it demonstrates the advantages of creating your own microprocessor-based autopilot: maximum flexibility and expandability by fully integrating the autopilot and the R/C control system.
Hardware level integration means that the onboard computer can control as many or as few aircraft and camera functions as we want. The downside is that the particular embedded processor we chose, the BASIC Stamp (which is the easiest to program), is also very limited in processing power and memory. But the same concept, extended to more powerful processors such as the Parallax Propeller or a Linux-based Gumstix, could be quite capable indeed, potentially allowing the autopilot to handle both navigation and stabilization functions, rather than using an off-the-shelf commercial unit for stabilization as we do in this UAV. Or, if you want something like Basic Stamp but more appropriate for a production UAV, follow along as we develop ArduPilot, the open source Arduino-based autopilot, here on this site
Features: Unlimited pre-set GPS waypoints, with programmable options such as circle and hold. GPS-controlled altitude hold. With Pentax A30 setup, autopilot can control camera to take pictures at waypoints or at a set interval along paths.
- Airframe: NSP Viking ($130. You'll need another $300 worth of batteries, a motor, and radio equipment in you don't already have them)
- Autopilot: Custom circuit board based on a Parallax Basic Stamp module, an EM406 GPS module and a FT639 Servo Controller chip all on a Parallax development board (someday we'll move that to a proper soldered circuit board). (around $200 all told). Note: if you don't mind the extra size, Parallax also has a very good servo controller board that will also work. There is code for each at the link below. A step-by-step tutorial on setting this hardware up can be found here.
- The software code is now in beta. You can read about it and download the files in this post.
- Stabilization: FMA Direct FS8 Co-Pilot (infrared sensors, $115)
- Imaging: Pentax Optio A30, which is the smallest high-res camera I've found that allows for IR shutter trigger, plus a Prism R/C-controlled IR trigger. (both are around $200). This is also good candidate for the IR stabilized camera mount described here, which doesn't require the Prism trigger.
- Target cost: between $700 and $900 depending on how much of the required stuff--such as a suitable camera--you've already got laying around.)
--As noted in this post, the Basic Stamp is easy to use, but somewhat limited. For a more powerful chip with built-in floating point, more memory and video functions (for real-time telemetry in the video stream, for example), you may want to consider upgrading to a Parallax Propeller (how appropriate!) chip. Paul Hubner has made a good start on writing the software needed here, and there's a very complete autopilot core here.