Gyros vs. Accelerometers
Some quadcopter flight control boards come equipped with only gyroscopes while others have gyros and accelerometers. The ones that have both are a bit more expensive. So what do gyros and accelerometers do? Well, understanding the underlying science makes my brain hurt and is beyond the scope of this blog post. However, for those who want to understand the finer points, a basic Google search for “accelerometers vs. gyros” yields plenty of good information. What I care about is how it effects the way my quadcopter flies. Here is what I have found…
How differently do they fly?
As a beginner quadcopter pilot, I notice a major difference in how the two types of flight control boards fly. Quadcopters equipped with gyros and accelerometers require virtually no stabilization by the pilot. They automatically stay level with the earth without the pilot having to learn how to “hover”. This is a great feature for a beginner because it makes the quadcopter much easier to fly. On the other hand, gyro only boards do a certain amount of stabilization, but still require piloting skills to keep the quadcopter level. Interestingly, more experienced pilots may actually like to fly without the additional stabilization accelerometers provide, because it gives them more control over the aircraft.
Recommended Flight Control Boards
Well written software/firmware is a must to correctly use the data provided by gyroscopes and accelerometers to keep the quadcopter level and stable. Also, the hardware itself must be good quality and within spec. I recommend avoiding cheap clones to insure you are getting a quality product.
Update – 7/19/12 Time has passed and new boards have come along, while others are not being manufactured anymore. I now recommend the Hobbyking KK2.0 Multi-rotor LCD Flight Control Board as a great choice for a low cost flight control board with gyros and accelerometers. There are lots of other good alternatives, some of which are listed here.
The two boards that I have used and recommend highly are the OpenPilot CopterControl and the FH-X46 TMF Pro . Both of these boards have gyros and accelerometers and do a great job of keeping quadcopters level and stable.
The CopterControl board is very flexibile and is highly configurable with the free OpenPilot GCS software. The default stabilization settings work well for most quadcopters. For more precise stabilization, the variables used within the stabilization algorithms in the firmware can be set in the GCS software.
The GCS software is great! Three other items GCS allows me to configure that are really helpful include:
- The startup speed of the motors
- Custom throttle curves
- Axis lock to keep the quad facing in one direction
One downside is that the CopterControl board is usually backordered and hard to get. However, the OpenPilot folks will soon manufacture a board called CC3D that should be more readily available.
FH-X46 TMF Pro
The TMF board is very much plug and play and is usually available, but it costs a bit more.
There are probably lots of other good alternatives available. Here is a link to a post I did a while back comparing price and features of various boards. The data in that post may be somewhat dated since new boards and features are being added all of the time.