Tutorial SMC3 Arduino 3DOF Motor Driver and Windows Utilities

I don't know if this help you out but did you install all related libraries with the sketch?

deeph

Hello, I have done all the steps in the tutorial and SMC utils works well for me but in SimTools it does nothing for me. Anybody knows what could be the problem?

Hi all, I am pretty new to the world of Sim racing and have been trying to familiarize myself with SimTools and SMC3 for the arduino. I don't have access to a pot but have 3D printed an optical disk that is fixed to the motor shaft. I am using a Photo Interrupt Module (PIM) to effectively count the gaps in the optical disk and this effectively gives me the same outputs as a shaft encoder. I was wondering how I could incorporate this into the SMC3.ino code so that it works the same way as the pots used. I have included a photo of the PIM and my code on the arduino IDE is pasted to the end of this post:

const int PIM_PIN = A0; // Analog pin for the photo interrupt module
const int NUM_SLOTS = 20; // Number of slots on the optical disk
const int SLOT_THRESHOLD = 200;
const float ANGLE_PER_SLOT = 360.0 / NUM_SLOTS; // Degrees per slot

unsigned long prevTime = 0;
int prevVal = 0;
float motorSpeed = 0;
long encoderCount = 0;
float currentAngle = 0; // Current angular position in degrees
bool clockwiseRotation = true; // Assume clockwise rotation initially

void setup() {
// Initialize serial communication
Serial.begin(115200);
}

void loop() {
// Read the analog value from the photo interrupt module
int val = analogRead(PIM_PIN);

// Check if the signal is below the threshold
if (val < SLOT_THRESHOLD) {
unsigned long currentTime = millis();
unsigned long elapsedTime = currentTime - prevTime;

// Calculate motor speed in revolutions per second (RPS)
motorSpeed = 1000.0 / (elapsedTime * NUM_SLOTS); // 1000 ms in a second
prevTime = currentTime;

// Calculate the change in angle based on the slot detected
float angleChange = ANGLE_PER_SLOT;

// Update the angular position based on direction (clockwise/anticlockwise)
if (motorSpeed > 0) {
// Clockwise rotation
currentAngle += angleChange;
clockwiseRotation = true;
} else if (motorSpeed < 0) {
// Anticlockwise rotation
currentAngle -= angleChange;
clockwiseRotation = false;
}

// Print the motor speed, encoder count, angular position, and direction
Serial.print("Motor Speed (RPS): ");
Serial.println(motorSpeed, 2); // 2 decimal places
Serial.print("Encoder Count: ");
Serial.print(encoderCount);
Serial.print(" Current Angle (degrees): ");
Serial.print(currentAngle);
Serial.print(" Direction: ");
Serial.println(clockwiseRotation ? "Clockwise" : "Anticlockwise");

// Update the encoder count
encoderCount++;
}

// Print the analog value
Serial.print("Analog Value: ");
Serial.println(val);

// Delay to stabilize readings (adjust as needed)
delay(10);
}

Any help would be appreciated. Thanks.

Good Morning,

I have been lurking for quite a while now and figured after reading enough, I would just get it. I was wrong. I ordered a DOF P3 and uses the orange sensors for feedback (pot?). I want to convert it from the ATMEGA2650 to the Arduino Uno, R3; this requires a rewiring.

I am a little confused with the code as to why pin 2 and pin 3 from the Arduino are not symmetrical to the IBT-2 H-bridge pins, on the diagram provided by @eaorobbie, while the code looks symmetrical. Specifically pin 3 is wired to both left and right enable, pin 2 is set to L_PWM, and pin 9 is set to R_PWM. I would have expected the following:

pin 9 set to left and right enable
pin 2 set to L_PWM
pine 3 set to R_PWM

For example, where motors are driven, the code looks "symmetrical from pin 2 and 3 in the Arduino"

Recalling that:
const int ENApin1 =2; // ENA output pin for Motor H-Bridge 1 (ie PortD bit position)
const int ENBpin1 =3; // ENB output pin for Motor H-Bridge 1 (ie PortD bit position)
const int PWMpin1 =9; // PWM output pin for Motor

"MyPWMWrite(PWMpin1, PWMrev1);" tell me that pulse-width modulation is sourced from Arduino, Port D, pin 9.

// Drive Motor Backwards
PWMout1 = abs(PWMout1);
PWMout1+=PWMoffset1;
if(PWMout1 > PWMmax1){PWMout1=PWMmax1;}
OutputPort &= ~(1 << ENApin1); // Unset Motor1 In 1
OutputPort |= 1 << ENBpin1;

// Drive Motor Backwards
PWMout1 = abs(PWMout1);
PWMout1+=PWMoffset1;
if(PWMout1 > PWMmax1){PWMout1=PWMmax1;}
OutputPort &= ~(1 << ENApin1); // Unset Motor1 In 1
OutputPort |= 1 << ENBpin1;

I would have expected something like:
// Drive Motor Backwards
pin 9 to send a PWM to left and right enable on IBT_2
pin 2 set to low on L_PWM
pin 3 set to high on R_PWM

// Drive Motor Forwards
pin 9 to send a PWM to left and right enable on IBT_2
pin 2 set to high on L_PWM
pin 3 set to low on R_PWM

Am I missing something in my logic or some part of the code? Or this a misunderstanding of how the IBT_2 works?

Thank you kindly, this is an awesome site and a lot of incredible builds out there. It blows my mind how much detail people put into their designs and appreciate your letting me join your community.

Hi, I have a MD13S 13A motor driver that I'd like to use for my sim rig, you can find the specs for the driver here: 13Amp 6V-30V DC Motor Driver (cytron.io)
I'd like to know how I would connect the DIR and PWM pins to the arduino. I assume that the PWM pin can be connected to pin D9 on the arduino but I'm not sure whether to connect the DIR pin to D2 or D3 on the arduino? Do I only connect it to one of them or perhaps both? Additionally, am I correct in assuming that I would use the SMC3 software in mode 1 for this particular driver?
Thanks!

I am running in mode2 and completely agree that it is by @RufusDufus, not @eaorobbie. @RufusDufus credited his diagram on page1 to @eaorobbie.

My question is either an electrical engineering question or a programming question as I am trying to understand why Arduino pin 3 is treated differently in the wiring diagram than pin 2, when in the code they seem equivalent. There is either a typo in the diagram or the code (neither is likely). It is more likely that my mental model for how the IBT_2 works for the enable and PWM pins is incorrect and I just need to understand why they are treated differently. Is it like putting a NPN and an PNP transistors in series as a totem pole connection of two complementary BJT's, also known as Push/Pull? Is there a reason for the difference to how pin 2 and pin 3 is wired in the Arduino?

I was able to assign Arduino pin 9 on the IBT to both R/L enable pins on the IBT_2 and use pins, 1 and 2 of Arduino for drive the motor bidirectionally through R_PWM and L_PWM. I realize in SMC3 we don't want to use pin 1 (Arduino) because we want that available for serial communication, so we use 2 and 3 (Arduino).

Here is my code. You will notice it is very similar in function to SMC3, but my wiring is slightly different in that I treat pins 1 and 2 exactly the same. SMC3 code doesn't work if I do it that way and it is not clear why.

My code works for driving a motor back and forth, which is most of what I need. Where it fails is that it doesn't incorporate feedback into the system so that two motors in phase eventually, mechanically drift apart.

#define Pin_D1_L 1 //Arduino pin 1 digital output RPWM
#define Pin_D2_L 2 //Arduino pin 2 digital output LPWM
#define Pin_E_L 9 //digital output PWM pin (analog output)

void setup()
{
pinMode(Pin_D1_L, OUTPUT);
pinMode(Pin_D2_L, OUTPUT);
pinMode(Pin_E_L, OUTPUT);
motor_stop();
}

void loop()
{
motor_stop(); delay(1500);//motor stop
for (int i = 0; i <= 65; i++)
{
analogWrite(Pin_E_L,65*sin(2*PI*i/360)); //drive motor CCW sine wave
digitalWrite(Pin_D1_L, HIGH);
digitalWrite(Pin_D2_L, LOW);
delay(7);
}
motor_stop(); delay(1500);
for (int i = 0; i <= 65; i++)
{
analogWrite(Pin_E_L,65*sin(2*PI*i/360)); //drive motor CW sine wave
digitalWrite(Pin_D1_L, LOW);
digitalWrite(Pin_D2_L, HIGH);
delay(7);
}

}

void motor_stop()
{
digitalWrite(Pin_D1_L, LOW);
digitalWrite(Pin_D2_L, LOW);
analogWrite(Pin_E_L, 0);//0-255
}

Ok this might be what I was looking for:

In essence, I am not sure why PMW is assigned to pin 9 in the Arduino code, and 2,3 nominally should be on equal footing in the code, but are wired differently. It is almost like 1.RPW 2. LPW should have been physically swapped with 3. and 4. R_EN and L_EN tracing back to PWM pin 9.

Mode 2 is probably running in "usage two" below
http://www.hessmer.org/blog/2013/12/28/ibt-2-h-bridge-with-arduino/



This paradox may be resolved in the following comment unfiltered:

"These boards definitely can’t be used with a single PWM pin. The half-wit chinese board torturer who designed this thing named the enable pins R and L but there is no relation to the driving direction. They are just the enable pins for each of the two half-bridges on the board. (The L pin for the right of them and vice versa) Unless you activate them both, there is no function at all.
Therefore, it is not possible using only one PWM pin without further parts. With some additional logic you could easily use one PWM pin and one direction select pin.

I can’t even articulate my anger against such people. This board must have consumed thousands of hours of good people trying to figure out why the directional enable pins do not enable any direction, bringing despair to beginners and spoiling a nice hobby for so many."

Hi, all I followed the tutorial but got stuck at the end.
I got the motors working and used the smc3 tool to test it. The only thing i see is that not my green line is moving but the yellow line is moving when adding pwmmax. Is this an issue? When i use motion to test it also does work.
But when using the simtool program i cant seem to get it working. I used the settings provide. See screenshots. But when testing with the output the motors wont move. I cant figure it out.

THanks it seems like it works. What i am confused about is using the utility software and the game engine. Am i correct that you configure the motors in the utility and those settings are saved somewhere? And then the game just adjusts the position slider? I first thought the utility was just to test the eniges not to use the to configure the motors. Are there any recommended settings for the utility program?

Hello, the other day I purchased an IBT-2, assembled two drives from what I had in the garage to test the firmware, configured it using the utility and attached it all to an old office chair. In the utility everything works well, in SimTools 1.3 it works well, but in SimTools 3 it works jerkily and when entering the settings menu the axes shift by 40 percent in pitch

This is what the trial version looks like

I have a question: has anyone tested the firmware with SimTool 3?