GeoCrawler 3 (BASIC Stamp autopilot)

Chris Anderson
DIY Drones

June 12, 2007

Description: This UAV is designed for 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.

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 [ http://www.nesail.com/detail.php?productID=3401 ] ($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 [ http://parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/CategoryID/9/List/0/SortField/0/Level/a/ProductID/7/Default.aspx ], a Parallax GPS receiver [ http://parallax.com/Store/Sensors/CompassGPS/tabid/173/CategoryID/48/List/0/Level/a/ProductID/396/Default.aspx?SortField=ProductName%2cProductName ] and a FT639 Servo Controller chip [ http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=323977 ] all on a Parallax development board [ http://parallax.com/Store/Microcontrollers/BASICStampDevelopmentBoards/tabid/137/CategoryID/12/List/0/SortField/0/Level/a/ProductID/126/Default.aspx ] (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 [ http://parallax.com/Store/Accessories/MotorServoControllers/tabid/160/CategoryID/35/List/0/Level/a/ProductID/376/Default.aspx?SortField=ProductName%2cProductName ] that will also work. There is code for each at the link below. A tutorial on setting this hardware up can be found here: Part 1 [ http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A16788 ], Part 2 [ http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A16832 ], Part 3 [ http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A16948 ], Part 4 [ http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A17767 ], Part 5 [ http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A19488 ].
The software code is now in beta. You can read about it and download the files in this post [ http://diydrones.ning.com/profiles/blog/show?id=705844%3ABlogPost%3A625 ].
Stabilization: FMA Direct FS8 [ http://fmadirect.com/products.htm?cat=29&nid=7 ] Co-Pilot (infrared sensors, $115)
Imaging: Pentax Optio A30 [ http://www.amazon.com/gp/product/B000LY1UMC/102-3459531-0862524 ], which is the smallest high-res camera I've found that allows for IR shutter trigger, plus a Prism R/C-controlled IR trigger [ http://www.hexpertsystems.com/prism/ ]. (both are around $200). This is also good candidate for the IR stabilized camera mount described here [ http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A2525 ], 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.)

Notes:

--As noted in this post [ http://diydrones.ning.com/profiles/blog/show?id=705844%3ABlogPost%3A625 ], 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 [ http://www.parallax.com/propeller/index.asp ] (how appropriate!) chip. Paul Hubner [ http://diydrones.com/forum/topic/listForContributor?user=phubner ] has made a good start on writing the software needed here [ http://forums.parallax.com/forums/default.aspx?f=25&m=179159 ], and there's a very complete autopilot core here [ http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A17208 ].

11:00pm