RC Nerf Tank [ II ]

step 15The 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.

tank 16.jpg

step 16Mounting 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!


step 17Camera 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.


step 18Adding 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.


step 19Wiring

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.


step 20Adding 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.


step 21Wireless 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.


step 22Final 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!


(Source instructables.com)

1 comment:

  1. A nice one...it looks like a fun project but I have to say that it's a good project.It certainly required some skills and I am fairly pleased with the results.It's design is completely different but looks nice though really looking forward to see this in complete shape.So best of luck and thanks for sharing.