Tag Archives: sensor

Sensors

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I’ve been thinking some time about the control and guidance system and came up with a rather simple and versatile solution. I’ve been playing around a little with some sensors mounted on breakout boards to make life a little easier. I decided to reuse those in the copter, since I plan to build only one.

Gyroscope

I’ve chosen the L3G4200D 3-axis gyro module from ST. Parallax have it mounted on a breakout board making it easy to interface. Its wide range (250-2000°/s) and fast communication (up to 10MHz SPI) makes it suitable for this project.

Accelerometer

Finding a suitable accelerometer was a bit harder. This’ll probably also be the most important sensor as well. I finally found the Bosch BMA180 triple axis accelerometer mounted on a breakout board from Sparkfun. It also has a wide range (±1g to ±16g) and a fast SPI interface.

Magnetometer

To achieve full 9 Degrees of Freedom (9DOF) I’ve chosen the HMC5883L 3-Axis Compass Module from Honeywell. Parallax have it mounted on a breakout board as well. It has only an I2C interface, but I don’t expect polling it as often as the gyro and accelerometer.

Altimeter

For low level flight (less than 3 meter) I plan to rely on ultrasonic sensors, but for higher altitudes I’ll have to rely on an altimeter and/or GPS coordinates. I haven’t looked into this very much yet, but I decided to go for the MS5607-02BA01 Micro Altimeter Module from Measurement Specialties – just because Parallax had a breakout board for that one as well. It states it has a 20 cm resolution. I’m not sure if I’m believing it…

The Quadrocopter project

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A couple of weeks ago I started building a little quadrocopter. My main reason isn’t actually having it flying nicely, but to learn a bit more in detail about how modern sensors work. All my electronic stuff has been stored in boxes for almost ten years, so I thought it was well about time refresh my mind a bit.

I quite soon realized a lot has happened during these ten years and, among things, found out that my old AVR programmer didn’t work any longer in a modern OS. Nor doesn’t every computer have serial and parallell ports…

Instead of investing in a lot of new equipment, I found an old laptop that actually had a rs232 port. Installing a 32bit version of Windows also solved a lot of driver problems. So, after some struggle, I had a simple development environment up and running and created the mandatory Hello World program on a simple ATmega8515 CPU.

So, now I just needed a fun project to work on. I recently saw this amazing Ted talk about flying robots, and I though I may give it a try myself. Maybe I’ll make it half way and actually make it flying 😉