Can Dual H bridge 2A motor driver work with DAGU Rover5 chasis (2.5 stall current)

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1

Hi

i was planning to Buy "Rover 5" 2 Dc motor , 2 encoder chassis from hobbyking with other accessories. however as a motor driver i found - "H-Bridge Motor Driver" which provides output to 2 motor but max current is 2A. whereas stall current for the motor is 2.5A. can i run the rover 5 without burning the motor driver?

specfications:

http://www.hobbyking.com/hobbyking/store/__37421__Arduino_Compatible_H_Bridge_Motor_Driver.html

Driver: L298

Driver power supply: +6V~+35V

Driver peak current: 2A

Logic power output Vss: +5~+7V (internal supply +5V)

Logic current: 0~36mA

Controlling level: Low -0.3V~1.5V, high: 2.3V~Vss

Enable signal level: Low -0.3V~1.5V, high: 2.3V~Vss

Max drive power: 25W (Temperature 75 degree Celsius)

http://www.hobbyking.com/hobbyking/store/__26274__Rover_5_Tracked_Robot_Chassis.html

Motor rated voltage: 7.2V

Motor stall current: 2.5A

Output shaft stall torque: 10Kg/cm

Gearbox ratio: 86.8:1

Encoder type: Quadrature

Encoder resolution: 1000 state changes per 3 wheel rotations

2

You COULD put a 2A fuse

You COULD put a 2A fuse inline with the motor. Then you would just blow the fuse instead of cooking your driver. That could get annoying and/or expensive though.

3

Give this board a test

http://robokits.co.in/shop/index.php?main_page=product_info&cPath=73&products_id=15

I have tested it to 3amps and it seemed fine.  Follow the instructions on the board and DO NOT SEND IT ALL ‘1’ (HIGHS) Break/stop with all ‘0’ (LOWS)

 

 

4

Thanks all

Thanks all

5

Hibeing a novice in robotics

Hi

being a novice in robotics , i decided to start with inexpensive parts. i have settled down with –

i am using chassis , which has 4 dc motors each rated as 3volt and 170mah stall current.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=26250

as a motor driver i am using 2 motor driver , which can run from 6-35volt and provide 2A per channel

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=37421

i do have a 5v/6v voltage regulator which will power my arduino and raspberry pi-

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=18521

the lipo i am using is of 11v 2200mah:

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=8932

now i am confused because i am afraid that using 11v lipo for 3v motor might fry the motor? is it safe to use 11v lipo for four 3v motor’s even though the lipo power is given to motor driver (i am not sure whether motor driver has any inbuilt regulator to handle such scenario)

do you think that 11volt 2200mah - can run raspberry pi, arduino and motor all together?

please help.

Thanks

6

how to control direction

hi

yes , this driver can work as per specs. i couldnt figure out how to control the direction from raspberry pi. it has only 4 pins. as per specs-  

->5 Amp. per motor capacity

->Works with any circuit that gives 3 to 5 v high output

Pin 1 : Motor 1 + forward

Pin 2 : Motor 1 - reverse

Pin 3 : Motor 2 + forward

Pin 4 : Motor 2 + reverse

i can associate these pins with PWM and change duty cycle. but do i have to give HIGH/LOW on those pin to change their direction?

i contacted robokits , below was response , i coudnt get :frowning:

-------------------------------

The driver supports max 250hz PWM signals. It does not have enable pin. You need to have 2 PWM’s given to two control pins for speed control in both directions.​

-------------------------------

i assume the code might be like- is it going to be the logic?

GPIO.setmode(GPIO.BOARD)

GPIO.setup(7,GPIO.OUT)

lr=GPIO.PWM(7,50) # 7th pin with 50hz
lr.start(0) #0 is duty cycle
lr.ChangeDutyCycle(new_value) # change speed of motor
GPIO.output(7,0) # change direction of motor1 - reverse
GPIO.output(7,1) # change direction of motor1 - forward
one silly question - spec says
Pin 5 : +5 V output (For external circuits like MCU Board)
Pin 6 : GND
do i need to connect these pins(5,6) with Rpi/arduino? do they provide logic level voltage information to the driver? or i just leave them as blank
7

issue closed

i have brought 4 motor and 4 channel driver of dagu. so this issue is closed :slight_smile: will start my project soon

8

You PWM the direction pin.

Sorry, did not see the question.

With this bridge you only use one pin at a time to control a channel.  So if you want to go forward on motor1 you would send your PWM to pin 1, and have a low (0) on pin 2.  If you want to go backwards, you would PWM pin 2 and make pin 1 low (0).  Having Pin 1 and Pin 2 low is a brake.  Never drive pin1 and pin2 or pin3 and pin 4 high (1) at the same time. This will short the driver out.  Easy to not do if you write your code correctly :slight_smile: