This is 2x bigger version of https://www.thingiverse.com/thing:1000713 redesigned for standard sized Emax servos like ES 3001 or metal gear ES 3005 (preferred). Items uploaded here are just those I've modified, take the missing ones from original model and scale them twice.
Update 2.4.2018: better driven wheels (
MyDrivingWheel-2) - I had problems with too hard tracks so this helps to start moving.
Update 29.4.2018: updated link to source model in summary.
light.stl - use transparent filament
- arms and bucket - make it as light as possible - it's a long lever in this bigger version and it can easily exceed torque of the servo
- free wheels are split to two parts for easier print (it still needs supports but not as much)
The servo-holes should match the servo quite exactly but they are higher (you need some space for cables). Use two pieces of
servo-fixer.stl per servo to affix it.
The "wire hollow" in the cabin roof is quite narrow but still can take a standard resistor. Just use more force.
Dont forget to make the headlights cable long enough - you need to be able to flip off the cabin.
I'm using piece of standard servo cable with servo "JR" connector. It has 3 wires:
- yellow / orange (signal, you don't need it)
- red (+)
- brown (-)
When you plug it into any slot of your receiver, lights will shine whenever the receiver is on (it works at least on my Spectrum).
3x Emax 3005 or another of the same size. Use metal geared servo for arm, plastic ES 3001 has too low torque.
4-5 cells NiMH is cheapest and easiest variant, just notice that most of receivers can take max 6V
8x 4x9x4mm (two for each free wheel)
4x 3mm white LED
1x 50 ohm resistor (current ~20.7 mA per LED with 6V source (=5 cells))
piece of wire and connector compatible with your receiver
Bolts and nuts
M4 bolts (sunken head) to affix free wheels
long M4 bolts with nuts to join halves
M3 bolts to affix wheels / arm to servos
You need to remove stops from two servos used to drive wheels. If you're using ES 3005 (it's analog) you have to:
- remove solid stops from gear (use small grinder)
- replace potentiometer with 2 resistors (ES 3005 has 4k7 ohm potentiometer --> 2x 2k2 resistor)
Servo insides with potentiometer...
... replaced by two resistors