Presentation on sensors in FIRST

[taichichuan]

Hi Gang,

I've attached a presentation that I gave at the DC FIRST workshop in early December. It goes through the majority of sensors used in FIRST, what they're used for and where you connect them. I hope this helps some of you understand how sensors can make your robots better.

HTH,

Mike Anderson
FRC #116

[taichichuan]

Hi Gang,

I've added some info on the new CTRE magnetic encoder that will be new for 2016.

Enjoy,

Mike

[GeeTwo]

All good stuff- thanks for putting this together!

One of the more troublesome aspects of selecting a rangefinder is not the maximum range that the sensor can detect, but the minimum. Inexpensive rangefinders seem to have a minimum range that is about 10% of the maximum range; often what you pay for in higher end range finders is a decreased minimum range. It should also be noted that while many rangefinders are linear in range (that is V=kr), some are approximately reciprocal (V=k/r), and others may have stranger response curves.

[taichichuan]

Originally Posted by GeeTwo

All good stuff- thanks for putting this together!

One of the more troublesome aspects of selecting a rangefinder is not the maximum range that the sensor can detect, but the minimum. Inexpensive rangefinders seem to have a minimum range that is about 10% of the maximum range; often what you pay for in higher end range finders is a decreased minimum range. It should also be noted that while many rangefinders are linear in range (that is V=kr), some are approximately reciprocal (V=k/r), and others may have stranger response curves.

Quite true. Especially with the infrared sensors, we've found that if you're too close, the distance is wildly inaccurate. Fortunately, many of the data sheets will warn you about this feature if you will simply take the time to read them. :-)

[GeeTwo]

Originally Posted by taichichuan

Quite true. Especially with the infrared sensors, we've found that if you're too close, the distance is wildly inaccurate. Fortunately, many of the data sheets will warn you about this feature if you will simply take the time to read them. :-)

That should probably be the key point to drive home: read the data sheet before you order!

[RyanN]

Some notes to improve it.

Slide 8 - Misspelled 'resister'.

Slide 24 - "dual cameras will allow you to do distance estimation" - True, but given the size of the game element, viewing angle of the camera, and full camera resolution, distance can be estimated.

Overall though, great overview of the types of sensors used.

Good job!

[taichichuan]

Thanks. I'll correct the typo.

Mike

[taichichuan]

Thanks. I'll correct the typo and add a note on using a single camera.

Mike