I am thinking about buying the DFRobot 4WD Arduino Mobile Platform and the Arduino Mega. Does RobotShot recommend a motor controller for four of the motors below?
• Motor Model: 130 Motor
• Output Mode: Two-way shaft output
• Gear ratio: 1:120
• No-load speed (3V): 90RPM
• No-load speed (6V): 180RPM
• No load current (3V): 120mA
• No load current (6V): 160mA
• Locked-rotor current (3V): 1.5A
• Locked-rotor current (6V): 2.8A
• Size: Long 55MM W 48.3MM high-23MM
• Weight: About 45g
robotshop.ca/pololu-dual-motor-driver-14a.html
I was thinking about using Pololu Dual High Current Motor Driver 14A 6V-16V along with Lynxmotion 7.2v 2800 mAH NiMH Rechargeable Battery BAT-04. I wan’t to wire the motors on each side in parallel. Will this controller and battery setup be adequate? Can these motors handle 7.2V?
robotshop.ca/pololu-dual-motor-driver-14a-2.html
robotshop.ca/nickel-metal-hydride-battery-packs.html
Thank you for your help. The DFRobot ROMEO specs say that it can “drive two DC motors between 7-12V and <1A each.” Isn’t that outside of the operating range of the motors? Also, these motors have a stall current of 2.8A @ 6V. If I were to wire each side in parallel wouldn’t that be a max current of 5.6A per channel? Do you stock something that can handle that much current and drive these motors within their recommended operating voltage?
I already have a few of the Arduino Mega that I have been using in other projects. I am probably looking for a motor controller and battery pack that can drive these motors.
Also, if I were to use Pololu Dual High Current Motor Driver 14A 6V-16V, what would happen if I used a 6V battery pack and the voltage supplied drops below 6V as the battery drains? Would the controller stop driving the motors?
Thanks,
lebowski
Hi lebowski,
Welcome to the RobotShop Forum. There is actually quite a range of motor controllers which would work with these motors and the Arduino MEGA, including the one you specified. The current should be about 2A per channel and the communication can be PWM, Serial, Alanog, R/C… (the Atmel chip is very versatile). At 7.2V, you are well outside the motor’s nominal operating voltage and the motors will not be very efficient, so it is not suggested. We suggest 4.8V to 6V battery pack which will allow you power both the Arduino (via the Vin pin) and the motors. Note that the 4WD platform has mounting holes for the DFRobot ROMEO microcontroller (based on and entirely compatible with Arduino) which includes a dual motor controller specifically for this platform. If you do not need all the analog and digital I/O of the MEGA, the ROMEO does have 8 analog pins (as compared with 6 on most other boards).
Hope this helps,
It is important to note that you never should reach stall, which would cause a motor to burn out very quickly. You should design for about 1/4 stall, which in this case would be about 600mA per motor. The ROMEO was designed specifically for the 4WD platform and many customers have used it without any issues. We have recently added a 2A dual motor controller shield from DFRobot which would be compatible with the MEGA microcontroller. The product number is RB-Dfr-58 and should appear on the website in a few days. If you use a motor driver outside its specifications, for example at 5.8V, it may or may not work. Dropping farther below that would guarantee that it does not respond to input commands. You would not damage the controller.
