### Author Topic: velocity  (Read 1137 times)

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#### g44

• Jr. Member
• Posts: 38
##### velocity
« on: April 01, 2010, 05:52:49 PM »
velocity .
« Last Edit: May 05, 2010, 06:42:50 AM by g44 »

#### Soeren

• Supreme Robot
• Posts: 4,672
##### Re: velocity
« Reply #1 on: April 01, 2010, 06:46:55 PM »
Hi,

I want to measure the velocity of the car
I want to feel  the exact velocity also if the car is slipping or if  there is a big friction and the car is deceleration
How I can do it ?
You don't really mean "to feel" it, right?
To measure it, count revolutions for a given time* of two wheels (eg. left front and back wheel) and as long as they're equal. Measuring both wheels will show slippage by a large difference in the time it takes for a revolution (or part of one).

* You measure the time for a full, half, tenth or whatever revolution and the inverse is a measure of velocity.

Maybe an accelerometer can help for this mission
A car going a steady 10, 100 or 1000 mph will have an acceleration of zero.

For this mission I want to understand how the old computer mouse and the new optical computer mouse works maybe it can help me to solve this problem
Start here and allways remember to Google such stuff yourself before asking!

Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Engineering is based on numbers - not adjectives

#### g44

• Jr. Member
• Posts: 38
##### Re: velocity
« Reply #2 on: April 03, 2010, 05:24:18 AM »
velocity .
« Last Edit: May 05, 2010, 06:43:17 AM by g44 »

#### g44

• Jr. Member
• Posts: 38
##### Re: velocity
« Reply #3 on: April 03, 2010, 12:22:46 PM »
Thanks Soeren.
« Last Edit: May 05, 2010, 06:44:35 AM by g44 »

#### Soeren

• Supreme Robot
• Posts: 4,672
##### Re: velocity
« Reply #4 on: April 03, 2010, 12:40:52 PM »
Hi,

I thinks that I want to prevent the slip with 2 optical mice in an optical feedback position control
One mouse should be enough, if you plan to "read" the road surface with it. You have to change the optics for that, to get a suitable focal length.

How I can do the interface between the controller and the optical mouse in the level of the device or with PS2 protocol ?
I was thinking more in line of stripping an old ball mouse and use the sensors to read the wheel speed, but if you use an optical mouse, you should find the datasheet for the camera-chip used (likely from Vishay) to get a direct line to the goodies.
Using PS2 will just be an extra layer of stuff to go wrong IMO.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?