POLL: What sensors do you use

[Rickertsen2]

What sensors do you use? What do you use them for?

[Denman]

for other, in our 2003 robot, we used a gyroscope thing to detect when we hit something and to correct the course correspondingly

we demonstrated it by running it along a flat surface then getting someone to kick it, and it would correct itself

[Rickertsen2]

Come on now ppl. 15 ppl have voted but only one has bothered to post anything. Give some descriptions.

[Lindsey]

Here’s the rundown on what we used and what for.

In 2003 we had:
- tilt sensor (to detect when we were on the ramp and help prevent us from tipping)
- limit switch (to keep the arms from closing beyond mechanical stops, prevent stalling the motor)
- gyro (to turn a specific angle to go to the ramp, auto mode)
- optical sensors (3 to detect when the robot crossed the line, auto mode)

In 2004 we had:
- current sensors (mainly for decoration we hooked up colored bar-graph readouts)
- pressure transducers (2? to make sure our center pivot wheels, mounted on pneumatics, were all the way down)
- limit switch (to keep the arms from closing beyond mechanical stops, prevent stalling the motor)
- optical sensors (to detect when the robot crossed the line, auto mode)
- gear tooth sensors (they count gear teeth & we used them to count wheel revolutions, auto mode)

Both years we had custom circuitry to help with the sensors.

I thinks that’s about it.
Lindsey

[Sparks333]

Team 1425's Robot (2004)
-2 limit switches on the top and bottom of our chain slider, so the chain wouldn't go too far and break the turnbuckles (it did it twice before we put them in.)
-2 more limit switches set up to bounce on a hex bolt, to act as encoders (tacky, yes, but we didn't have time for anything else.)
-1 potentiometer, used for the sole purpose of changing programming variables on the fly.
-1 standard switch, used for turning Autonomous mode from left to right to
off.
-1 pressure transducer, to detect when we could use all 60 psi to lift.
-(almost) 2 current sensors, but they were being stupid.

Sparks

[Al Skierkiewicz]

We use microswitches for position and limit detection. Pots for rotating position info. (Pots were used on our arms and are an essential part of our crab driving modules. They are used in closed loop servos) Let us not forget that pots are an integral part of the supplied servos. We started using current sensing several years ago and it was a real eye opener when compared to match play and battery terminal voltage. We have used the gyro in auto mode to help run straight and get to a final position. We experiimented with the IR transducers but found that there was faster ways to get to the side goals this year.

[Andrew Schuetze]

In 2004 we were fortunate to finally add a programming mentor and could do more than run the default program. We used an array of four optical sensor for line following and a seperate sensor for proximity to the wall. We also used some limit switches to stop rotation on our biggens ball arm. We had the pressure transducer on the compressor in hopes of cycling it but issues with autonomous occupied the ten weeks until regionals.

I am very much looking forward to this season as we have added a second programming mentor and an electronics mentor.

Question1: Is the gyro chip still legal? I seem to recall that it wasn't included in the kop last season but I am fuzzy in regards to whether it could be one of the off the shelf electronics purchases.

Question2: I am researching encoders and would appretiate any reference data for sensor that you have used and liked. Part #, online catalog, ...

Thanks ,

APS

[Marc P.]

Limit switches are a must for any mechanical device driven by a motor. Hard stops are necessary too, but without a limit switch to tell the RC when the device has reached it's end, the motor will continue to drive the device, even after it's hit the hard stop. Every motor-driven mechanical function I've ever worked on has always had limit switches in every critical place.

We have often used pots to determine the angular location of an arm or device, and I think team 25's arm this past season is the best example of a creative use for pots I've ever seen.

Optical sensors/banner sensors are one of the easiest methods of counting traveled distance accross the field. Paint gray/white/silver wheel hubs with a black matte paint at equal increments, and you've got a decent/cheap/easy counter.

In 2001 we used the gyro/angular accelerometer to self balance on the ramp carrying two goals (in under 30 seconds ).

[vtrehan]

We didn’t have many sensors last year as we were well.... rookies .

This year we are planning to work with an IR sensor mounted on the wheels for distance calculation (and we have a working prototype), and we used opto sensors for line following, we also had some limit switches for various purposes.

We are actually shopping around these days for a more reliable sensor for distance calculation, so if someone can recommend something more reliable and simple, please let us know .

Thanks,
Vivek.

[Rickertsen2]

Originally Posted by vtrehan

We didn’t have many sensors last year as we were well.... rookies .

This year we are planning to work with an IR sensor mounted on the wheels for distance calculation (and we have a working prototype), and we used opto sensors for line following, we also had some limit switches for various purposes.

We are actually shopping around these days for a more reliable sensor for distance calculation, so if someone can recommend something more reliable and simple, please let us know .

Thanks,
Vivek.

In a word words: encoders. Search the forums and you will find several detailed threads. They are very easy to use and extremely accurate

[Astronouth7303]

I coded for (Whether or not they were placed on the bot, but most were) numerous sensors.

• 3 pots (shoulder, arm, & hand position)
• 1 switch (arm limit)
• 4 banners (quadrature)
• 1 current (for the hand, made a overload mech around that)
• 1 pressure (the simple pnuematic one, only controlled the compressor)
• 1 Gyro (compass)

I think that's it.