What sensors should I use for 15 seconds autonomous?

I was wondering what sensors I should I use for 15 seconds autonomous.

I have line followers, quad encoders, potentiometers, 1 light sensor, ultrasonic sensors, and bumper switches.

Any advice would be really helpful.

Minimalistic is probably best if you are looking for maximum efficiency, aka a good balance of point value, speed and reliability. I would suggest potentiometers, some form of encoder and bump sensors.

Suggest using encoders on drive, potentiometers onlift and depending on your design, encoders or limits on intake

My autonomous is able to pick up 7 sacks and score the 7 + 1 pre load in either trough only using time.

So does mine. Though encoders on the wheels and arms can help.

That is what we had for our first competition, and I hated it. If the battery was low and we tested it on full battery, the autonomous would be short every time.

We use 4 Integrated Motor Encoders’s, 2 Potentiometers, and 6 bumper switches for our autonomous. When you get PID on the arm, it helps you SO much in the long run.

But that is not as fun. Cleansweep I won 3 programming skills awards using only time and had one of the highest scores at worlds. Charged batteries has become an exact science for me.

lol

It is a lot easier with timing, but I don’t want easy.

Good for you tabor :slight_smile: I’m glad timing has served you well.

“Served me well” o god no
I just find it annoying to put sensors every were also my Tabor drive would be hard to put sensors on.

I was just trying to tell the thread creator that is possible to use time for a simple 15 second autonomous.

We had a very successful autonomous using time, we had to make sure that we started every match with fresh batteries for it to be accurate. With that said, once we started using encoders we were able to give out autonomous more moves than Michael Jackson. If you keep it simple time will work, If you want to do more than head to the trough and dump then I would use some sensors.

I think you need to think about this the other way around, decide what the autonomous is going to achieve and then choose the appropriate sensors for the job.

I’m actually really liking the ultrasonic for driving a distance and positioning (assuming that you are angled perpendicular to the field perimeter), it’s absolute and (unlike quad encoders on wheels) does not get biased by wheel slip.

I’d really recommend using sensors as your autonomous will become much more reliable regardless of the charge on your battery. You’ll also learn a lot more programming an autonomous mode utilizing sensors vs. just going with running motors for a specific time value.

We always used encoders on our wheels and either potentiometers or limit switches on our mechanisms. Limit switches are probably the easiest to use because they’re either on or they’re off.

The ultrasonic sensor is great, especially if you can get a few of them to automatically position your robot in the same spot each time.

Robot C has a great tutorial section on sensors here: http://www.robotc.net/vex_full/

All of them.

you need to look at what you want the autonomous to do and chose what sensors you need to accomplish the task you want accomplish.

some of the most common sensors and purposes are listed below:

  1. Ultrasonic - used to determine the distance from the field perimeter.
  2. Quad encoders - used to determine how far a wheel has traveled.
  3. potentiometer - used to determine the location of something that does not rotate more than 180 degrees (usually a lift arm)
  4. switches - commonly used to tell when part of a robot has contacted the field(used to move until the robot hits a wall or something) or when part of the robot has hit a limit(used to limit the motion of an arm so the driver doesn’t accidently damage the robot by powering the lift or other part of the robot into a hard stop.

use what you need to achieve what you want.

hope this helps:D

I agree with others here, you need to decide what task you wish to accomplish before you can decide what sensors to use. Our robot that we competed the season with was deadly accurate with quad encoders, but the robot we are building for Worlds will use encoders, potentiometers, a gyro, and an ultrasonic range finder to complete the given task. In our case the gyro is the only sensor that is really optional, but I think my son needs the challenge of programming it, and if he can’t we can get by without it.

I suggest doing a flow chart of what you want to do and then take it from there. The flow chart is a great addition to your engineering notebook as well!

And remember, the simpler you keep it the more sucessful you will likely be! If we were not competing for the design and excellence awards we would not have attempted the complexity that we did. The range finder is probably the most accurate sensor you can use aside from limit and bumper switches, and quad encoders can be accurate if you choose a path that will eliminate the chances of wheel slip.