NanoSeeker

Let's Make Robots Robots
1

NanoSeeker is a very small, autonomous underwater vehicle.

Almost all of the structural parts were 3D printed on a Dimension uPrint, including the propeller. It has:

  • AVR ATmega328 microcontroller
  • Bluetooth module as a serial port
  • Honeywell HMC6343 i2c 3-axis compass, with integrated 3-axis accelerometer
  • Provisions for a very small, SPI pressure sensor (not installed at this time)
  • Custom made linear actuators for dive plane and rudder, using pager gearmotors
  • 2 Lipo batteries wired in series (7.4 volts)
  • Magnetic on/off switch

I've ordered a new tube for it, in clear acrylic, so it should look pretty cool once that is done.

I built an early version of this sub before I had a 3D printer, but it didn't work out very well...

Here's what some of the parts look like, hot out of the printer:

The dark globby stuff is support material from the printer, which dissolves away when you soak it in a special solution.

This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/nanoseeker
2

Awesome little AUVI was

Awesome little AUV

I was wondering if your linear actuators are operating in open loop mode or if there is some feedback mechanism that is not shown? And how deep is it designed to dive? How long can it operate with that power system?

Very nice work!

 

 

 

3

NanoSeeker has a dive plane

NanoSeeker has a dive plane and a rudder - both are sitting behind the propeller, which is run by a third pager gear motor you can’t see very well. The second video shows all three in action. I’ll have to take it apart to really get a good look at the third motor - it is sandwiched between the two PCBs, and stuck almost all the way into the 3D-printed rear section.

4

Closed Loop

They can be closed loop, although I haven’t written the code for that yet. The little white triangular-shaped pieces that slide along on the threads - there is a very small (1/16" diameter x 1/4" long) rare earth magnet embedded in each, and an analog hall effect sensor on the PCB underneath. It produces a nice distinct signal over the entire range of travel. Took me a while to find a decent small analog hall effect sensor that handled magnets in that orientation, though. The two sensors are hooked to A/D inputs on the 328, and of course I have full PWM control over all three motors. I can’t do closed loop with the thruster motor, but I didn’t really see the need given the environment.

5

Cool, and well done :-)A

Cool, and well done :slight_smile:

A little sub is on my list as well. How does it dive? Do you just use the hydroplane to dive?

The two motors are for the propeller and the hydroplane or are they for rudder and hydroplane and the motor for the propeller is underneath the board? You see, there are some questions which would best answered by more pictures :wink:

6

Cool, it’s moving :slight_smile: Ok, no

Cool, it’s moving :slight_smile: Ok, no need to take apart the whole thing. I understand where the third motor is located now. 

What is your idea with that pressure sensor, do you wan to make it more autonomous?

7

Lipstick Camera—

In the next interation, presumably the clear acrylic version, it would be great if you could integrate a lipstick camera and a Micro SD card to record and store video.

8

Yes, that is definitely an

Yes, that is definitely an option. The idea is to have a modular payload system so you can add mission-specific sensors (like a camera). Basically, you pop off the nosecone, add on an intermediate piece, hook up the wires, and then plug the nosecone into that.

9

The pressure sensor allows

The pressure sensor allows the robot to know its depth. Water pressure increases linearly with depth, so with a pressure sensor you can figure out at least one piece of where you are.

10

Good work

Well made, more people should collect this bot.

11

Good work

Well made, more people should collect this bot.