I have a couple of Robot kits that I bought from the RobotShop. They were the first robots I built, and my young daughter helped me. We went with some low cost kits to start.
2WD with caster: robotshop.com/en/2wd-beginne … d-old.html
4WD : robotshop.com/en/smart-car-chassis-4wd.html
My daughter and I have had a good time building these, but the motors suck. I don’t blame anyone, the kits are really cheap. Great for what they are. I like the chassis on both, but I would like to upgrade the motors. Very little power. The robots spin in place very slow, and almost can’t on very low carpet. I have motor controller shields and Arduino boards I will keep. I am just trying to figure out what would be a “step up” in motors. Eventually I will move up to a hundreds of dollars platform, but I would like to stay with a $10-$20 per motor with these platforms for now. My 4WD has a separate 4xAA battery supply for the motors, so I will likely go with 6v motors.
I was looking at something like this: robotshop.com/en/2101-140rpm … motor.html
I’ve been drowning in numbers trying to compare the yellow motors stall torque (800 gm/cm = 11 oz/in 90 RPM) to others, such as the one above (4.7 Kg/cm = 57oz/in 140 RPM)
The 140 RPM motor would be faster and have 4 times the torque if I am doing this right (and have the right numbers for the yellow motors) Does this seem like a reasonable option? Does anyone have experience with these? Are there others for a little bit more that would be better recommended?
Hi,
Thank you for posting on RobotShop’s forum.
As we didn’t test the Smart Car Chassis 4WD with other motors, we can’t confirm that either of the Gear Motors you’ll choose will be appropriate for the chassis.
Choosing the gear motor with the right torque/RPM ratings won’t probably be an issue, mounting them will, since the output shaft of the Gear Motor needs to be directly compatible with the wheels.
Here is some suggestions that might work with the Smart Car Chassis 4WD :
]GM9 - Gear Motor 9 - 90 Degree Shaft/:m]
]GM3 - Gear Motor 3 - 90 degree Shaft/:m]
]200:1 Plastic Gearmotor 90 Degree Shaft/:m]
Hope this helps.
Regards,
Thanks for the reply. I guess I didn’t thing too hard about the wheels. The wheels that come with the kits will likely have a difficult time mounting to other motors. They have a square attachment. Hmmmm. I appreciate the suggestions, as they do fit the wheels, but I am not sure those plastic gearbox motors are much better?
Hi,
The gear motors we suggested are almost similar to the one from the Smart Car Chassis 4WD as they probably use the same DC motor.
The only difference seems in the reduction (gear ratio). Keep in mind that higher the reduction, higher the torque and lower the RPM.
GM9 - Gear Motor 9 - 90 Degree Shaft : RPM : 66, Torque : 43oz.in, Reduction : 143:1
GM3 - Gear Motor 3 - 90 degree Shaft : RPM : 38, Torque : 50oz.in, Reduction : 224:1
Before testing any of these gear motors, you might want to try to run yours at 6V or 7.5V (their operating voltage range should be 3V ~ 12V)
Regards,
