17 replies to this topic

[Spammy786]

Hi Guys

 

I have done some minimal work on the Netduino for our company and it was so interesting, I decided to order 1 for myself with a few extra components and try to build a simple 2WD robot that I can control using my android phone over Bluetooth. I got the Bluetooth parts working with my PC to test. I will code the android stuff at a later stage using Xamarin Android.

 

The Problem I am having is controlling the 2 motors. I will post my poor attempt of code below. I found a few examples online but I could not get any of them to work. I am running firmware version 4.3.1.0. So I think the reason some of the examples do not work for me is because they are using an older version of the framework. I tried a cool library I found on codeplex, the link http://uplibrary.codeplex.com/

I tried to this to work but I was not so lucky. I tried a few breakpoints and nothing seems to break but the motors will not turn, they just refuse to turn

 

The Components :

1 x Netduino Plus 2

1 x Bluetooth Device (Got this working well with my PC and Netduino, used a framework called 32feet.Net)

1 x Magician Chassis

https://www.sparkfun.../products/12866

1 x Motor Driver 1A Dual TB6612FNG

https://www.sparkfun.com/products/9457

 

Wiring of Motor Driver :

Netduino to TB6612FNG breakout
DIO0 = Standby
DIO1 = AIN1
DIO2 = AIN2
DIO5 = PWMA
DIO6 = PWMB
DIO8 = BIN1
DIO9 = BIN2
Ground to ground 

TB6612FNG breakout to motors
AO1 = Red motor lead (Right)
AO2 = Black motor lead (Right)
BO2 = Black motor lead (Left)
BO1 = Red motor lead (Left) 

using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using SecretLabs.NETMF.Hardware;
using SecretLabs.NETMF.Hardware.Netduino;

namespace MotorController
{
    public class Program
    {
        public static void Main()
        {

            OutputPort stby = new OutputPort(Pins.GPIO_PIN_D0, true);
            TB6612FNG motors = new TB6612FNG(Cpu.Pin.GPIO_Pin1, Cpu.Pin.GPIO_Pin2, Cpu.PWMChannel.PWM_5);
            motors.MotorModeA = MotorMode.CW;
            motors.MotorSpeedA = 50;  // Set the motor to 50% speed   
           
            while (true)
            {
                motors.MotorModeA = MotorMode.CW;
                motors.MotorSpeedA = 50;  // Set the motor to 50% speed  
            }

        }

    }
}

[Spiked]

Wild guess since I do not have any of the pieces, but I suspect changing the motor mode and speed over and over again as fast as possible might have unintended consequences.

 

Try setting them both, sleep 1 second then set speed to 0; get rid of the while loop.  If that works you need to rethink your logic.

[Spammy786]

using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using SecretLabs.NETMF.Hardware;
using SecretLabs.NETMF.Hardware.Netduino;

namespace MotorController
{
    public class Program
    {
        public static void Main()
        {

            OutputPort stby = new OutputPort(Pins.GPIO_PIN_D0, true);
            TB6612FNG motors = new TB6612FNG(Cpu.Pin.GPIO_Pin2, Cpu.Pin.GPIO_Pin3, Cpu.PWMChannel.PWM_5);
            motors.MotorModeA = MotorMode.CW;
            motors.MotorSpeedA = 1;
            Thread.Sleep(2000);
            motors.MotorSpeedA = 2;
            Thread.Sleep(2000);
            motors.MotorSpeedA = 4;
            Thread.Sleep(2000);
            motors.MotorSpeedA = 6;
            Thread.Sleep(2000);
            motors.MotorSpeedA = 8;
           
            //while (true)
            //{
            //    motors.MotorModeA = MotorMode.CW;
            //    motors.MotorSpeedA = 50;  // Set the motor to 50% speed  
            //}

        }

    }
}

Hi Spiked, thanks for the prompt reply, I tried what you said and the motor still does not turn

I just have 1 motor connected for now, If I can get it to work with 1 then I can get it to work with 2. I cant seem to find out why the motors don't turn. Any other advice ?

[Spiked]

Motor speed 8 may be too low. My motors generally do not start until around 30 or so. Stick with 50 for now.

 

Other than that, perhaps take a pic to show your wiring. Maybe someone who has the device can spot an issue.

[Spammy786]

Ok, I will take a pic of the wiring and upload it. Il change the motor speed back to 50 and give that a try.

Il keep yourll post,

[Spammy786]

Hi Guys

 

Heres a link to my wiring, the code above as not changed, Im pretty sure im missing something small. Im not sure what it is. Probably a part of my brain perhaps

Thanks

 

Link to wiring

http://s14.postimg.o..._Controller.jpg

[CW2]

There is no power supply for the motors - VM is not connected (?)

[Spammy786]

I thought the motors will get its power from the board because I am supplying power to the board from the N+2. 

I have a battery holder that takes 4 AA batteries that came with the chassis. That as a plug that connects straight to the N+2 power socket.

So now I need to buy additional batteries for the motors and solder the positive to VM ? and ground to Ground ?

Can I not use the 4 AA Batteries to power up the N+2 and the motors ?

[CW2]

The motor driver IC has separate power supply for motors (VM) and logic (VCC). You can use the batteries to power both Netduino and motors (if it is a standard AA battery holder, you should be able to insert a wire between battery and the positive contact lead and solder it to motor board VM input).

[Spammy786]

ok so solder 2 wires to the (4xAA battery holder with barrel jack termination)

Connect the positive to VM and the negative to Ground on the N+2

If this solves my problem, I am having a drink tonight

Thank you for your prompt reply. I will give this a try.

[Spiked]

That will get you going, but down the road keep in mind there is a reason logic voltage and motor voltage are usually kept apart. There are several ways to accomplish isolation, one the easiest/best being 2 different batteries.

 

The problem is, in some configurations the motor pull can drop the voltage below what the logic can tolerate, even if just for a microsecond the results can be bad. Also motors, being mechanically/electrically connected (brushes sparking) tend to introduce 'noise' on the circuit and cause all  kinds of hard to find problems.

 

Again, hook it up as you described, see if it works, then think a more permanent solution.

[Spammy786]

using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using SecretLabs.NETMF.Hardware;
using SecretLabs.NETMF.Hardware.Netduino;

namespace MotorController
{
    public class Program
    {
        public static void Main()
        {

            OutputPort stby = new OutputPort(Pins.GPIO_PIN_D0, false);
            TB6612FNG motors = new TB6612FNG(Cpu.Pin.GPIO_Pin1, Cpu.Pin.GPIO_Pin2, Cpu.PWMChannel.PWM_5);
            motors.MotorModeA = MotorMode.CW;
            motors.MotorSpeedA = 60;
            Thread.Sleep(100000);
        }

    }
}

I tried taking the power directly from the 4 AA batteries and connected 1 end to VM and the other to GND and it still does not work. When I measure VM and GND I get 3v, so now there is power going to the motors. Is there anything else I can try ? I mean instead of connecting a Motor, Can I connect an LED to A01 and A02 and pulse the LED. just so we know the hardware is working correctly, there must be an easier way to debug this. if I connect the motors directly to the battery they turn quite fast, so I know the  motors are working.

[Spammy786]

Any ideas guys ?

[CW2]

Well, it does not seem right to have VM = 3V for 4 AA batteries, it should be around 6V (4*1.5V) for regular alkaline or 4.8 (4*1.2V) for NiMH cells. Where have you soldered the wire on the battery holder? 3V would mean you are using only two batteries, i.e. wrong terminal.

[CW2]

Can you share the photo of the actual wiring?

[Spammy786]

Sure, I shall take out a pic tonight and upload it, no problem. 

I was reading this article online : http://bildr.org/201...612fng-arduino/

And it talks about the StandBy Pin. Could that be my problem ? Im not sure. I did set it to true and ran the program, did nothing, I set it to false and it didnt do anything. So im not entirely sure.

[CW2]

I have checked the datasheet again and I think there is a problem with control signal voltage levels: if you power the motor control board by 5 - 6 V, the Netduino 3.3V outputs do not have high enough voltage (V_IH = 0.7*V_CC = 0.7*5 = 3.5V).

 

So, connect VCC to Netduino 3.3V, STBY to 3.3V, VM to 5-6V.

 

To manually test the motors, connect PWM to 3.3V and then either IN1 or IN2 to 3.3V. 

[Spammy786]

Hey CW2

 

Your suggestion above worked so I investigated the code a bit further. The problem was the PWM code. See all the examples I found, PWMA was connected to pin5, So we were choosing channel5, So basically we physically connected it to pin5 to the N+2 but in code you have to choose PIN0. I think this is because I am using 4.3.1.0.  The code below works

Thanks everybody for your help. 

using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using SecretLabs.NETMF.Hardware;
using SecretLabs.NETMF.Hardware.Netduino;

namespace MotorController
{
    public class Program
    {
        public static void Main()
        {
            OutputPort stby = new OutputPort(Pins.GPIO_PIN_D0, true);

            //motorA
            PWM motorA = new PWM(Cpu.PWMChannel.PWM_0, 10000, 1, true);
            OutputPort a1 = new OutputPort(Pins.GPIO_PIN_D1, false);
            OutputPort a2 = new OutputPort(Pins.GPIO_PIN_D2, false);
            motorA.Start();

            //motorB
            PWM motorB = new PWM(Cpu.PWMChannel.PWM_1, 10000, 1, true);
            OutputPort b1 = new OutputPort(Pins.GPIO_PIN_D8, false);
            OutputPort b2 = new OutputPort(Pins.GPIO_PIN_D9, false);
            motorB.Start();


            while (true)
            {
                //this controls motorA
                a1.Write(false);
                a2.Write(true);
                motorA.DutyCycle = (double)0.7;

                //this controls motorB
                b1.Write(false);
                b2.Write(true);
                motorB.DutyCycle = (double)0.7;
             }
        }
    }
}