Accelerometer Test

A simple circuit to test the functionality of a 3 axis accelerometer I purchased from Sparkfun.com recently. It uses 3 analog to digital converter channels on a PIC 16F887 to read the accelerometer values and sends the data through an RS232 port on the micro. The data is then sent though a couple XBee wireless transceivers to a simple VB app on my computer.

Category:

Science & Technology

Tags:

• accelerometer
• pic
• microcontroller
• xbee
• wireless
• transceiver
• logic
• level
• converter
• usb16F887

[IblesjunkieMrMcCoy]

I presume you're using the MMA7260Q breakout there and it has 4 g settings, which g level did you set it to there?

[vasago17]

@IblesjunkieMrMcCoy, You are correct, this is the MMA7260Q breakout board from SparkFun Electronics. I used the 1.5g settings, tying GS1 and GS2 to ground. These pins have an internal pull-down resistor so you can leave them disconnected for this setting as well. I used the 1.5g setting because this gives you the maximum resolution for small changes in acceleration.

[vasago17]

@IblesjunkieMrMcCoy, You are correct, this is the MMA7260Q breakout board from SparkFun Electronics. I used the 1.5g settings, tying GS1 and GS2 to ground. These pins have an internal pull-down resistor so you can leave them disconnected for this setting as well. I used the 1.5g setting because this gives you the maximum resolution for small changes in acceleration.

[hohenheim1107]

Hi, i was wondering if you have a blog or something to see how you used the pic16F887 to sen data to computer, because im using the same pic to control the xbee, but im having troubles to send data, i dont know if the trama is wrong, or the pic. are you using the api mode to send data ?, and how is your data frame on the pic to send on the xbee ? Saludos!!

[vasago17]

@hohenheim1107 Unfortuanetly I don't have a blog or any online resource for you to see how I configured the XBee transceivers. I had a hard time setting them up at first too since. I used the XBee Pro Series 2 transceivers which are more for mesh networks rather than simple point to point serial comms. You have to set one up as the base station and the other as a node on the network. I'll have to hook them up to my computer an retrieve the setting for you.

[rashidme]

hey, nice work. I was wondering if i can use the accelerometer in an autonomous helicopter to achieve a hover.

[vasago17]

I think you probably could to some extent. Since this is a 3 axis accelerometer, the roll, pitch, and z-axis acceleration could be measured with the accelerometer. If there isn't any positive or negative acceleration in the z-axis and no tilt on the pitch and roll, it would be assumed that the helicopter is level and not ascending or descending. You wouldn't be able to measure the yaw of the helicopter though. I was also thinking about doing this, and it's why I used wireless transceivers.

[florezescobar]

Hi, I'm trying to do something like you did with this, but i have a Parallax Accelerometer. I'm wondering if you could give some guidance with the SPI port configuration for the PIC, because I'm lost.