Intro: Tank Platform
In this Instructables I will show how to build a simple and effective platform for any Robot project or Remote Control project. This Tank platform is great base for any robot design as it goes over rough terrain with ease. The other great plus with this design it can carry a lot of weight for there size. So there is endless possibles with this design.
The motor this platform uses can be control by any means. I use an cheap RC car to control the motors.The gear box and motor combo can deliver different gear ratio settings to suite your application. The gear ratio I use is 114.7:1 @ 4.5V. This ratio work well with the remote control that I use. I have try other ratios but this over heat the transistors on the RC board.
The this Tank platform use two motor so it use skid steering to turn. So you need least need a two channel RC car to make this project but most RC car have at least two channels anyway.
I will show both the new and old design. The old design will be known as Mk1 and the new design Mk2.
Step 1: Tools and Parts
I got all the parts for this platform from Jaycar ElectronicsJaycar Electronics. The RC car I got from a local market for a few dollars.
1. Double Motor Independent 4 Speed Gearbox / Axle Assembly Tamiya ITEM 70097
Jaycar Cat no. YG2741 $22.95
2. Tamiya Track & Wheel Set (You need two if you want to build Mk2)
Jaycar Cat no. YG2867 $16.95
3. 2 X Tamiya Universal Plate Set
Jaycar Cat no. YG2865 $8.95
4. M3 stand off posts 25mm
Jaycar Cat no. HP0907 $5.95
5. M3 bolts
Jaycar Cat no. HP0400 $2.50
6. M3 nuts
Jaycar Cat no. HP0425 $2.95
7. Cable ties
Jaycar Cat no. HP1200 $1.85
8. 3 by 1 AA battery holders
Jaycar Cat no. PH9203 $0.95
9. RC car any will do mine cost me $20
10. Switch on/off
Jaycar Cat no. ST0300 $2.95
All prices in AUS$
1. Philips Screw Driver
4. Soldering Iron
Step 2: Control Board
I got this cheap RC car from the local market. I pull apart to find a nice layout of components on the board. Clearly mark as well so this will be a big help when wiring it to the motors and battery pack.
The control board has two wire that go from the steering motor and to the drive motor. These get solder onto the new motor in our gearbox. I put left and right signals onto the right motor; forward and reverse onto the left motor.
When you turn on the board, you may found that the motor is going the wrong way just swap around the two wires going to the motor.
There are other ways to power and drive these two motor but this a simple and fun way of doing it.
Step 3: Details in Wiring Board
Now we have the board remove from our RC car that I got from the markets. We have to wire it to our new gearbox and motors that will drive the tracks. The RC boards is a two channel receiver. So the steering motor that went to the steering of the car will go to the left motor on our new gearbox. The motor that sent the car froward and backward will go to our right motor on our new gearbox.
Step 4: Fabrication of Gear Box
The first step in this project is building the gearbox and motor assembly. I supply a photo that the gearbox came with. The gear ratio that I use is 114.7:1 @ 4.5 volt. As long you follow the step list below in the photo you will be fine. I do recommend that when use this gearbox for a long time or over sand or dirty terrain that use some machine oil to re-lube the gearbox. As the gear are expose to the elements.
Step 5: Fabrication of Base
Fabrication of the base plate, all I did is to notch out the base using a pair of side cutters. This is where the motor and gearbox sits. Then you attach the gearbox and motor to the platform using the screws that the kit supply.
Step 6: Road Wheels and Idle Wheel Assembled for Mk2
I bought two Tamiya Universal Plate Set. So i have enough screw and other bits and pieces to build this new design Mk 2. I also needed two wheel and track set to build the Mk 2.
Mk2 is a little more complex. You need four right angle flanges. The two these are cut down so we can fit an extra pair of road wheels. Then I screw them to the base, then the idle wheel flange get screw to the base as well.
I use the extra wheels in the second kit to make enough wheels for this new design. I use four pair of road wheels. The idle wheel is the same size as the rear sprocket and road wheels. Now that does both plat form.
Then you insert four rods into the right angle flange. Then you install three of the larger road wheels. Then repeat for the idle wheel, which use the same size wheel as the road wheels. The sprocket is then place on the motor output shaft.
Step 7: Road Wheels and Idle Wheel Assembled for Mk1
Mk1is simple in it design it just uses three road wheels. The road wheels assembled is different from Mk 1. You only need one Tamiya Universal Plate Set. As you only need three pair of road wheels. You screw the right angle flange to the platform. Then you screw the front idle wheel assembled to the platform. Then you insert four rods into the right angle flange. Then you install three of the larger road wheels. Then repeat for the idle wheel, which use the biggest wheel in the set. The sprocket is then place on the motor output shaft.
Step 8: Tank Tracks
Now we enter into tracks. This process is trial an error until I was happy with the tension of the tracks you want some play so they don't fall off when turning and going over obstacles. I have shown in the first photo what length tracks you need for the Mk1 then in the second photo what tracks you need for Mk2.
All you do is place the tabs inside the the hole of the next tracks. Then you repeat until done the full length of track. Then you place track over the idle wheel and sprocket. Then you pull track around the road wheels. Then you check to make sure that the track has enough play in them.
Installing them is easy. I place the tracks over the drive sprocket and idle wheel. Then grabs the bottom of the track and drag under the road wheels.
After I install both set of tracks. I just check the tension of the tracks. As shown below this track has pass. You can move the motor and gearbox forward or back to increase or decrease tension on the tracks.
Step 9: Installing Battery Pack
I use three single AA battery pack to give me 4.5volt for the control board. All I do is just cable tie them down to the platform. Then trim the excess on the bottom of the platform.
The you wire the three AA battery packs together in series and install a on/off on the positive side that going to the control board. Then check with some fresh battery that you have 4.5volt coming out of the battery pack using a voltmeter.
I had to put a stand off because the new control board was larger than I thought. So these battery are on the roof of tank platform. Then the whole roof section get screw onto this stand off.
Step 10: Test the New Tank Out
Driving this tank take a little bit of skill. As it use skid steering to turn if you want to make a right turn let go the left motor control switch. When wanting to make a left turn let go the right motor control switch. When going forward you must push both control switch forward. But after a while you get use to driving this Tank. Here a couple of photos of the Tank out and about. Thanks for viewing my instructable.