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Zombie 8E (R8) - Construction

The Video about the Zombie 8E monster truck

You can buy the Zombie 8E on Gearbest.

Base car Zombie 8E

DHK Hobbie Zombie 8E RC model car
Figure 1:
Rover number 8 is based on a commercially available model car, the Zombie 8E. The dimensions are 52 x 37 x 21cm and the weight including the drive battery is 3600g - it's for sure no tiny chassis for a robot. The diameter of the wheels is 15cm resulting in a ground clearance of approximately 6cm so this car is made for rough terrain. Included in the package is a leightweight plastics body with a spoiler, the drive battery with a charger and the remote control in pistol grip design. Receiver, battery, motor and controller are all mounted on the chassis - it's ready to run, there is nothing to be wired up. Motor controller and receiver are in plastic boxes so that the electronics is protected from splash water - the Zombie is not made for driving fully under water.

DHK Hobbie Zombie 8E RC model car
Figure 2:
The rear wheels are connected through a torsion bar and it's a construction with a long spring travel. Same is true for the front wheels. You can adjust the springs with a nut and also change the upper mount point of the shock absorbers to get either a large ground clearance or a lower center of gravity.
DHK Hobbie Zombie 8E RC model car
Figure 3:
All four wheels are driven by one brushless motor type 3670 with 2030 revolutions per minute per volt.
Even with all four wheels in the air the motor draws a current of more than 7A. When accelerating with the wheels in the air the current increases to more than 30A - high electric power is converted into mechanical power.
The maximum voltage of the motor is listed with 14.8V, the empty load current with 4A.
DHK Hobbie Zombie 8E RC model car
Figure 4:
The 3s drive battery has a nominal output voltage of 11.1V and a capacity of 2600mAh - the Zombie ships with a charger for Lithium polymer batteries having 2 or 3 cells. It's no power charger - the maximum current is no more than 1A. With that it takes almost 4h until the battery is fully charged, indicated by second LED turning green.
The remote control needs 4 AA batteries that are not included in the package.
DHK Hobbie Zombie 8E RC model car
Figure 5:
I have printed a holder for my smartphone and installed an app to measure the maximum speed of the car. The top speed on my test track is 45.5km/h. With a mass of 3.6kg we get a kinetic energy of 287 Joule that's in the Zombie at full speed. That might cause an expensive impact crater if you hit an object! The Zombie is no toy for the kids, but a tiny racing car for the big boys...
DHK Hobbie Zombie 8E RC model car
Figure 6:
Driving slowly is tricky if you are in extremely rough terrain and another issue in low speed driving is caused by the differentials:
Whenever a wheel looses contact to ground, most of the drive energy is forwarded to the wheel that's in the air. The Zombie is made for fast driving and that's where differentials are needed to give the car a better stability.

Conversion to rover R8

Parts list:
Part Pieces Remark
DHK Hobby Zombie 8E 1 Basise car
Raspberry Pi model 3 1 Central barin
Raspberry camera module 1  
Micro SD card 8GB 1 4GB are enough
Cabel with plugs for GPIOs Steckern Raspberry Pi 1 30cm, female/female
DC/DC converter 1 Voltage supply Raspberry Pi

The conversion of the Zombie into a browser controlled rover is still in progress. More infos will follow as soon as R8 is prepared for first test runs.

DHK Hobbie Zombie 8E RC model car
Figure 7:
To turn the Zombie into a robot, I have ordered a Raspberry Pi 3, a camera module and a DC/DC converter.
As you can see I did not handle the Zombie gently during my test runs...

Test drives

Follow me on Twitter (@RoboSpatium) if you'd like to get a notification whenever R8 starts a mission.

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