Hi
I know that a single motor driver can handle up to 1A of current but what if I have several?
I have 4x 12v 760mA motors that I want to run simultaneously.
2 connected to base shield and 2 connected to port 1 and 2 with motor drivers.
Also I have a 12v battery pack that can easily supply the required 3-4 amps.
Is this a safe setup?
When does it become necessary to use the GND/V-M terminals on the motor drivers and base shield to supply additional power to motors?
I thought it’s ok to connect 4 motors on the Baseshiled simultaneously. But you should better not to run or stop the motors immediately in high pwm value (I think the limit pwm value is 100 in this case). Set up delay() in the code to prevent overheating or the restart of arduino.
Forgive my ignorance. I’m not sure about what is DNG/V-M terminals. Does it mean a power supply? If it does, I think whether you use it is depended on the loading of your structure.
I’m building a mobile robot that needs to move around fast and react fast. The 12V motors that I’m using are relatively high RPM and don’t have a gearbox so torque isn’t that great which means at PWM 100 ~ 5V the robot is likely to just stand still. They’re the best that I could find. Makeblock’s own motors are just too slow for me unfortunately.
By GND/V-M I mean the 2 little “external motor power” connectors on this picture:
There seem to be similar GND/V-M connectors on the base shield.
What are they for?
The driver IC can handle up to 1.2A avg and 3.2A peaks so that should be more than enough for one motor.
Correct me if I’m wrong but I think the amps just go through the motor driver IC and not though the arduino?
The base shield has only one TB6612FNG chip though which is used to drive both motors that are connected directly to the base shield? Is it going to have a problem with 2x760mA motors? 1.52A being slightly more than 1.2A.
If ~3A total for 4 motors can cause problems for the base shield then would using these “external motor power” connectors on the driver board help? Would the RJ11 cable need to be modified for that so current doesn’t flow back to the base shield? I’m assuming the V-M wire would need to be disconnected? If so then what color is it? I don’t have a RJ11 crimper.
Just thought I’d chime in with an idea? We’ve built a robot using the 25mm motors from MakeBlock and 11.1V LiPo batteries. The speed isn’t shabby as you can see in this video:
Here we’re using a normal Arduino with a protoshield and two L293D driver IC’s (http://www.adafruit.com/products/807) soldered on top of each other (for 1A+) The IC goes quite hot when driving full speed for a little while so I’ve thought about trying other IC’s that can pull more power. However - if you want really high speed/response, you should probably look at the UBEC’s used to drive RC cars. They can deliver massive amounts of power really fast.
I think the current could be divided in to two parts, the control current and the drive current. The control current should go through the Arduino, and the drive current would go through the driver IC.
For the “external motor power”, the bigger is used to connect to the PORT_1&2 (the red PORT) on the baseshield, or you can also solder the power wire directly to the small external motor connector.
It’s correct that the TB6612FNG on the baseshield is used to drive the motors connected to baseshield directly.
Thanks jenschr. I’m leaning more and more towards a similar route. I put together a little mockup driver yesterday evening with arduino pwm and some transistors which seems to work just fine. But I’m not confident enough in electronics skills to run it at higher current yet.
The L293D seems to be designed so that these center ground pins are used for heat dissipation. Perhaps you just need to solder a heatsink on there with some fat wires and you’re golden. I’m going to give L298N a shot. There are some dirt cheap driver boards on ebay. http://www.ebay.co.uk/itm/400603190168 2A per channel and a nice big heatsink. Says it needs additional +5V supply which isn’t a problem for me.
