Artificial Horizon Progress 1

Today was a crucial day for this project because I tested the accelerometer breakout-board at work with an oscilloscope to view the actual variations in voltage associated with the movement of the board.

Just a few days ago I finished the assembly of the board. I planned to use 4 springs attached at one end to the 4 corners of the PCB and at another end to a solid back piece, so as to move the board and then release it, to come back to its original position. This didn't work unfortunately, looks like I need some serious springs, and the trouble of finding them is just not worth it.

Let me show you a couple of photos of the finished board:

In this last photo you can see the connector with 8 pins and 6 cables and a 3 pin connector for the power supply (don't worry, only two pins are actually used)



I stole a 3.3 V voltage from the second pin from the left and placed it on the last pin which is the SLEEP pin, and as you guessed it is activated in 0, so I need to set it to 1 so I can get a reading out of the X, Y and Z pins.

I have left 2 pins unconnected, because I want to leave the accelerometer in its default range of 800mV/g and a maximum of ±1.5 G detected on any axis. Thanks to the reading I got today from the oscilloscope, this range of detection is perfect for my application.

I must admit that this type of sensor is truly amazing, at a level state, the X and Y axis are at mid-supply (i.e 1.6V) meaning no G is detected, while Z axis signals it is sensing 1G (i.e. 2.4V). If I turn the sensor up-right, the Y arrow on the PCB points down so the Y pin is at 2.4V, meaning 1G, which is correct, because it is sensing the natural attraction force of the earth. Now if I turn it up side down, the Y pin is at 0.6V meaning -1G(the arrow for the Y axis is pointing away from the earth)

Feeling pretty happy right now... I leave you with my messy desk:

Shopping again

I went shopping for parts that help me mount and interface my PCB accelerometer to the PC/104 system from my Faculty.

So I bought :

• 2 9x15 cm perforated test boards
• 1 NSL 8 pin connector
• 4 springs hacked from 4 identical pens

Here are some pictures:



The design will become apparent later on, as It is hard to describe it in words.

I must mention that I have not tested the accelerometer yet, I will do that as soon as I solder the parts enumerated above.

First success and another challenge

I managed to finish the Etch a Sketch project. It has been a good learning trip for me, and I can not wait to start another project.

Today was a good day to pay tribute to international mail service, because I received an important package. My license project implies the use of an accelerometer, and after long searches on the Internet, I ordered the part from Sure Electronics, a company based in China. Well it came and can't wait to start fiddling with it.

Here is a picture of it:It's called 3-Axis low-g Accelerometer MMA7260 prototype PCB, and it measures the G forces on all 3 axis of orientation, it has analog outputs so I must use an ADC to convert the output voltages to useful digital data.

I will make another post to show you how I will mount this PCB onto a bigger control surface.