Outdoor Robot

[OZ_341]

If you are going to be around little kids you might want to consider firing something besides tennis balls. And you certainly want to carefully consider exit velocity, firing safeguards, etc.

For that eventual day when someone gets hit (and it will happen) you want it to be something soft and/or very low velocity. A high speed tennis ball could actually do some serious damage.

[HumblePie]

Originally Posted by JonathanZur1836

You don't want dirt & mud in your transmission, so I suggest building something with minimal chain & protected gearboxes. Also, if your motors are going to be running constantly, you may want to find some way to cool them.

Agreed. You could start with a set of Nanotubes as the basis for a simple 4WD or 6wheel drop center with the front wheels unpowered. With no chain and all the gearboxes enclosed (except for lightening holes) you can enclose the tubes with Lexan (or even tape if you clean it well enough) to keep the gearboxes safe and fingers out. If you add fenders over the wheels and a solid belly pan, that should keep most of the crud out.

I won't speak to the electrical side, as others are much more qualified.

We're working on this approach for a baseball pitching robot at the request of the local minor-league baseball team. I'll post photos when done.

[Kevin Selavko]

Thanks everyone for your help!
I'm thinking we will use the ammo boxes for the electronics and the pelican boxes for the batteries. Any holes Ill cover over with Sugru. To shoot, nerfballs, and cover the whole thing in lexan. And also I think we will use tamper proof screws so that no-one can unscrew anything.

Do you know if the RC receivers have the right pulse width to Jaguars or Victors? Also does anyone have any experience with tamper proof screws/bolts?

[Alan Anderson]

Originally Posted by Kevin Selavko

Do you know if the RC receivers have the right pulse width to Jaguars or Victors? Also does anyone have any experience with tamper proof screws/bolts?

Victors were designed to use the same PWM signals as RC servos. Jaguars will work, but won't get the full range of outputs unless you recalibrate them. You might need a signal booster, depending on the receiver's ability to supply current.

I think that tamper-proof hardware isn't really appropriate unless you intend to be leaving the thing unattended for any length of time.

[Kevin Selavko]

Do you have any links to a whitepaper or instructions to recalibrate the jags?
Thanks.

[PAR_WIG1350]

Originally Posted by Kevin Selavko

Thanks everyone for your help!
I'm thinking we will use the ammo boxes for the electronics and the pelican boxes for the batteries. Any holes Ill cover over with Sugru. To shoot, nerfballs, and cover the whole thing in lexan. And also I think we will use tamper proof screws so that no-one can unscrew anything.

Do you know if the RC receivers have the right pulse width to Jaguars or Victors? Also does anyone have any experience with tamper proof screws/bolts?

Don't use the triangular 'tamper proof' bolts. These are the easiest type to defeat since one can usually find a Torx driver of hex key that fits. Similarly, avoid really expensive proprietary stuff, think tri-wing or square. Both are very secure (unless you find someone from Canada) and if you use an uncommon size the security will be further enhanced. The other option is one-way screws, but they would make maintenance a pain.

[Kevin Selavko]

Thank You!

[Dan_Karol]

This Major Qualifying Project at WPI was designed to inspect the thickness of the ice on frozen lakes for ice skaters.

They water proofed the robot by integrating a cavity inside the robot that is sealed when the robot is in operation. Its made out of Polycarb. and features a rubber ring around the interfacing pieces. All of the electronics are water tight and it might serve as "prior art" in your search.

[slijin]

Originally Posted by Kevin Selavko

Do you have any links to a whitepaper or instructions to recalibrate the jags?
Thanks.

See the TI webpage for links to various whitepapers.

To recalibrate, power up the Jag, hold down the USER button, then send the commands you want to be in the following order: full backward, full forward, then neutral. Release the USER button and wait for the LED to flash green, which indicates a good calibration.

To reset to factory calibration, hold down the USER button, then power the Jag, release, and wait for the LED to flash. I don't remember the correct color pattern.

[Kevin Selavko]

Thanks so much!
So will this allow them to work with vex controllers?

[slijin]

Originally Posted by Kevin Selavko

Thanks so much!
So will this allow them to work with vex controllers?

Yes, recalibrating Jaguars to Vex controller outputs will allow you to obtain the full range of control.

Vex controllers work fine; there's a robotics class at our school in which students develop a basic drivetrain and use Vex controllers (I'm not sure which type, though) to control Victors to drive the robot.

I'm not too familiar with the code structure/commands, though I can't imagine it to be too complicated.

[Kevin Selavko]

Thanks!