Toy Tank Hacking

Here are some photos of a toy tank that the local H.E.B. had on sale after Christmas.

The front of the box with the tank and action figure removed.

Tank Autopsy

The tank has 4 sections. The microcontroller is the little board located in the top of the turret.

Snipped the wiring to separate the base from the rest of the components. Also had to desolder the wiring going to the motors since they were wired together. The tank would only go forward or reverse originally. By desoldering the wiring and attaching new wires, we will be able to control each motor individually.

Here I have replaced the speaker with a L298 Motor Controller from HVW Technology. I also added an on/off toggle switch by drilling a 1/2" hole in the base and running the positive battery terminal lead through it.

Here is the base put back together. The cables running out the top are power, ground and the motor control cables that run to the motor controller. The headlights still work too!

Tank with a Parallax Ping))) Sensor controlled by an old Basic Stamp I.

Another view.

View of replaced battery pack. The original toy used 4 C cells giving a maximum voltage of 6 V. With a little Dremel tool work, space was made to hold a 6 AA cell pack which yields 7.5V. This results in much better performance of the motors.

Updates

Feb 4, 2006 - Added a

Basic Stamp I and a

Parallax Ping))) sonar sensor. Source code

here

Jan 27, 2006 - On a tile floor the tank is barely able to turn left and right about its axis (by moving one track forward and the other reverse). I think this gives one a clue as to why the tank originally had the motors wired together so that it could only go forward and reverse. I suspect that the problem may be insufficient voltage. In a turn the lights noticably dim. The four C cells provide a little less than 6 volts with no load. Turns require that the tank tracks "skid" across the surface which is a lot of resistance to overcome. I suspect that there is simply insufficient power available to overcome the friction. I think that the next step is going to be to figure out how to make it a 6 cell system (9 volts) to see if that helps.

Video

short MPEG-I video (2.2MB) showing the tank doing basic obstacle avoidance. This is still with the 6V original battery configuration.

Another video (2.9MB Quick Time) doing the same run but with the improved battery pack. A lot faster!

This page is maintained by EricLundquist

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