![Mounting turret and motors to the base](http://www.instructables.com/image/FH720S3FTM72P16/Mounting-turret-and-motors-to-the-base.jpg)
Drive shafts
I
had to make some custom shafts to mount the wheels to. I was originally
just going to modify some allen keys of the right size but I ended up
getting some 5/16" stainless steel hex bar. I turned the end down in my
lathe and cut 1/4-20 threads on the end. Screws on both sides of the
motor keep the shaft from moving out of place.
Attaching the wheels
The
wheels are stock tires from a Traxxas E-Maxx monster truck. The wheels
were donated by some friends who had upgraded their truck to fancier
wheels. I made up some more blocks and shafts to mount the other wheels
and supported them with bronze bushings.
They attach to the shafts with a 1/4" locknut and a rubber backed washer to keep the wheels from slipping.
![Attaching the wheels](http://www.instructables.com/image/FJPOPZIFTM72P1P/Attaching-the-wheels.jpg)
Mounting the Vulcan
I
decided to use magnets to mount the gun to the turret. The benefits of
this are the gun is easy to remove and I don't have to drill that many
holes into the thin nerf plastic.
I'm using a powerful magnet I
got out of a computer hard drive, I screwed a thin piece of steel to
the turret that will act as the anchor for the magnet.
Modifying the Vulcan
I needed a way to pull the trigger remotely, and like the turret I'm going to use a servo.
For
anyone wanting to build remote controlled projects servos are the way
to go. You can modify them to spin 360 degrees or leave them stock if
you just need a back and forth motion. You can get a RC transmitter,
receiver, and servos fairly inexpensively if you shop around a bit.
I
mounted the servo to the gun with a small aluminium mount and tapped
threads directly into the nerf plastic, it seems to hold up okay and the
servo easily pulls the trigger.
Adding the camera and laser
I
got the wireless camera system from a place called China Vasion for
less than $30. It doesn't have the greatest range or quality in the
world but its tiny and the price was right. To mount it I just popped
into into place on one of the 'tactical' side rails of the gun. These
rails would normally hold various nerf accessories.
I got the
laser pointer from a local pest control place as a free gift type thing.
I was having a heck of a time trying to mount it and I'm pretty
displeased with the final result, even though it works reliably. I
simply cable tied a mini servo to push down on the laser button. The
laser has a magnet built into the base of it, so I just glued another
magnet to the front of the gun to mount them together. I will have to
come up with an improved mounting method for the next version.
Mounting the battery
The
main system battery is a 24V 3000mAh 'Battlepack' NiCad. To mount it I
machined some aluminum standoffs on my lathe and then used a strip of
polycarbonate to hold it down. Some foam acts as shock absorbing
material.
My mini lathe is my fanciest tool, I got it for $480 and have been pretty pleased with it.
12Main electronics
To
control the drive motors I'm using a Sabretooth 2X10 speed controller
from Dimension Engineering. The receiver is a standard Futaba 7 channel
unit. Its tuned for 75Mhz and is legal for ground use.
Stiffening the frame
I
added some 4" x 0.125" aluminium flat bars across the wheel mount to
stiffen the frame up and hopefully keep stuff from bending. I will be
using these are the mounting point for the armour panels.
Adding armor panels.
I
cut up some more of that 0.1" scrap aluminum to act as the armor
panels. The jigsaw does a really nice job as these and is pretty
accurate too if you have a steady hand. Cutting fluid really helps out
for this type of thing, I used a few drops of A-9 aluminum cutting fluid
and it literally cuts twice as fast, plus its easier on your power
tools and your blades.
They bolt onto some 0.5" thick polycarbonate triangles that also allow the front and back panels to slope.
The sound system
I like adding sound to things.
Shown
here is a pair of 100W speakers I got from a surplus electronics store
for $20. I wish I would have shopped around a bit because I found some
similar ones for half the price later on.
The amplifier is from
an electric go kart I made a few years back that had a similar sound
system. I think I got it from radio shack originally.
To
control the tunes I'm using my old 1st generation iPod nano. The battery
is pretty much gone and you only get about 2-3 hours on a charge but
its more than enough for this project.
Mounting the speakers
I
used a jigsaw to cut the holes in the side armor panels. The cuts were
pretty rough around the edges but the speakers cover that up nicely. :P
Best part is now I can listen to tunes as I work!
Camera voltage regulator
The
wireless camera runs off 9V nominally, going any higher will probably
fry it. I wanted to hook it up to the main 24V battery so I built this
regulator circuit to run it.
Its basically a 9V voltage
regulator, a support capacitor, and two diodes. I designed it so that I
can hook both the 24V battery up to it as well as the solar backup
system. If the 24V battery dies or the robot loses power the camera will
automatically switch over to the solar power so I can see where it is.
I
added this ultimate paint schematic to show the circuit. Since the
power supplies (24v battery and 12v solar) share common ground and are
not wired in series you won't ever see 36V. The nature of diodes means
only the side with the highest voltage (normally the battery) will pass
through. If the 24V drops below 12V (really really dead) or gets shut
off somehow then the 12V solar will pass through its diode and the
circuit remains powered.
Adding a power switch
To
turn the tank on and off I'm using a automotive store switch I got for
$4. Its rated for 35A so it should be more than enough for what I need. I
mounted it on the bottom side panels between the wheels where it
hopefully will not get switched off accidentally.
You can also see the grounding stud in the polycarbonate motor mount to tie the negative battery wires together.
Wiring
I hate wiring things, I'm not very good at it and I don't enjoy it very much. But it has to be done so...
Here
is a shot of the insides, its prettystraight forward and a little messy
as I cut most of the wires extra long just in case. I had to extend the
servo wires attached to the guns so I went to the local hobby store and
bought a small roll of 3 conductor servo wire and spliced it to the
existing cable.
Adding the solar panel
I
wanted the solar panel to act as a charger but its only designed to
charge 12V lead acid batteries like you would find in a motorbike or
ATV. I'm going to look into building a 24V charging circuit for the next
version.
For now the panel acts with the voltage regulator to
act as an emergency backup power system for the camera in case something
goes wrong. If the main battery dies or power is somehow lost the
system will switch over to solar for the camera. That way I can at least
see where the tank is and whats happening to it. I mounted it with
adhesive backed velcro which is great stuff for mounting things you
might want to remove often.
Wireless setup
These are the parts that let me view the camera from my computer.
The laptop is nice since its mobile but I can use any computer that I install the drivers for the video capture adapter to.
The
silver box is the receiver that came with the camera. It needs a 12
volt power supply to run which also comes with the camera kit. (not
shown)
The black box lets me convert the TV component cables to
USB to use with a computer. Its a Sabrent USB Audio Video Capture
Adapter that I got from Tiger Direct.
Final product
There
she is, just before her first real test. For the most part it works
well but there are some things that will need upgrading in the future.
To see it run check out the video in the very first step. Thanks for
reading!