| ??? 09/02/11 21:06 Read: times |
#183596 - Response Back Responding to: ???'s previous message |
I try to describe w/o revealing product - move in any direction till someone shout 'stop', then go back to where you came from.
if this operation works, all is OK. MEMS gyros and acceleration are not exacting devices. The lower the cost the less repeatable and accurate they tend to be. the cost can be the equivalent of the HW to receive GPS I'll leave it to you to evaluate parts and their costs. I played with Analog Devices parts which were pretty expensive. (~15$ each) From the bit of playing around I did with such devices a few years ago I would say that successful application of these things requires -
- calibration will that be needed when the only use is as above I would think calibration is needed simply because if you wanted the gadget to track back home accuratly you have to be able to compensate for errors in motion detection due to transducer device tolerances and the errors introduced in device mounting. Sensors can sometimes also be affected by other nearby things. that add to the error band but which are not likely to be able to be calibrated out. monitoring of the inclination of the carrier platform (tilting) how critical for up to 25 degrees? this could be a problem. Some sensors will have outputs that vary from horizontal to vertical by a trig relationship. When wanting to translate the the sensor value back to a horozontal reference frame you need to know tilt to know how to apply the translation equations. Some of this may apply to your application and some may not. - temperature monitoring and compensation will that be needed when the only use is as above consider temp constant during the above operation but not the same when doing same thing next time Sensor outputs varied with temperature on the devices I played with. If you do not compensate how can you properly interpret the sensor outputs. Maybe it can null out if the idea is to take readings till the STOP and then simply reverse motions to return the gadget home whilst hoping that the sensors basically put out the negative of the initial readings. (Although the concept of "negative" is a fuzzy one when you are thinking of a anlyzing motion in a three axis space). - and lots of software. not an issue (mass market) That may be the "fun" part. I'll let you define what "fun" is. Michael Karas |
