My contribution to the increasing entropy, and eventual heat death of the universe
Archive for the ‘Uncategorized’ Category.
I’ve been reading though the Art of Electronics again, and often find youtube videos help clarify various points. Here’s a list.
I found this write up very useful: and the other writeups on that site. These videos were nice too:
BJT:
MOSFET:
Differential (OpAmp first stage)
Focusing on getting the captouch controller on this panel working under Linux.
This display: here
Uses this datasheet: here
Which is this captouch controller: here
Raw display module datasheet: here
Initial testing with a Buspirate v4, powered by Buspirate 3.3v supply, pullups enabled:
Buspirate setup commmands, final command scans I2C bus:
m 3 1 2 e 2 W P (1)
Output:
I2C>(1) Searching I2C address space. Found devices at: 0x70(0x38 W) 0x71(0x38 R)
Attached to a Linux System, appearing in i2cdetect now need to compile a kernel module:
Some info from chipworks: http://chipworks.force.com/catalog/ProductDetails?sku=CYP-CY8CTMA340&viewState=DetailView
Some interesting info in Chinese here: http://www.go-gddq.com/html/s25/2013-05/1128993p3.htm
Including this schematic:
Another one ( http://www.touch-link.com/case/6870533111.html ):
I was trying to use a STP42D306 stepper with a SeeedStudio Motor Shield V2 on an Arduino. This is a bipolar 2 phase stepper motor. I needed to modify the code to get it working as the SeeedStudio example is for a Unipolar motor. The code used is below. And here’s a pic of the setup:
No guarantee that I’ve done it correctly, but the motor spins clockwise/anticlockwise. There are some nice diagrams of the stepping process here.
// Demo function:The application method to drive the stepper motor.
// Hareware:Stepper motor - 24BYJ48,Seeed's Motor Shield v2.0
// Author:Frankie.Chu
// Date:20 November, 2012
#define MOTOR_CLOCKWISE 0
#define MOTOR_ANTICLOCKWISE 1
/******Pins definitions*************/
#define MOTORSHIELD_IN1 8//8
#define MOTORSHIELD_IN2 11//11
#define MOTORSHIELD_IN3 12//12
#define MOTORSHIELD_IN4 13//13
#define CTRLPIN_A 9//9
#define CTRLPIN_B 10//10
const unsigned char stepper_ctrl[]={0x27,0x36,0x1e,0x0f};
struct MotorStruct
{
int8_t speed;
uint8_t direction;
};
MotorStruct stepperMotor;
unsigned int number_of_steps = 200;
/**********************************************************************/
/*Function: Get the stepper motor rotate */
/*Parameter:-int steps,the total steps and the direction the motor rotates.*/
/* if steps > 0,rotates anticlockwise, */
/* if steps < 0,rotates clockwise. */
/*Return: void */
void step(int steps)
{
int steps_left = abs(steps)*4;
int step_number;
int millis_delay = 60L * 1000L /number_of_steps/(stepperMotor.speed + 50);
delay(millis_delay);
if (steps > 0)
{
stepperMotor.direction= MOTOR_ANTICLOCKWISE;
step_number = 0;
}
else if (steps < 0)
{
stepperMotor.direction= MOTOR_CLOCKWISE;
step_number = number_of_steps;
}
else return;
while(steps_left > 0)
{
if(step_number%4 == 0) {
digitalWrite(MOTORSHIELD_IN1,1);
digitalWrite(MOTORSHIELD_IN2,0);
digitalWrite(MOTORSHIELD_IN3,0);
digitalWrite(MOTORSHIELD_IN4,0);
digitalWrite(CTRLPIN_A,1);
digitalWrite(CTRLPIN_B,0);
}
if(step_number%4 == 1) {
digitalWrite(MOTORSHIELD_IN1,0);
digitalWrite(MOTORSHIELD_IN2,0);
digitalWrite(MOTORSHIELD_IN3,1);
digitalWrite(MOTORSHIELD_IN4,0);
digitalWrite(CTRLPIN_A,0);
digitalWrite(CTRLPIN_B,1);
}
if(step_number%4 == 2) {
digitalWrite(MOTORSHIELD_IN1,0);
digitalWrite(MOTORSHIELD_IN2,1);
digitalWrite(MOTORSHIELD_IN3,0);
digitalWrite(MOTORSHIELD_IN4,0);
digitalWrite(CTRLPIN_A,1);
digitalWrite(CTRLPIN_B,0);
}
if(step_number%4 == 3) {
digitalWrite(MOTORSHIELD_IN1,0);
digitalWrite(MOTORSHIELD_IN2,0);
digitalWrite(MOTORSHIELD_IN3,0);
digitalWrite(MOTORSHIELD_IN4,1);
digitalWrite(CTRLPIN_A,0);
digitalWrite(CTRLPIN_B,1);
}
//PORTB = stepper_ctrl[step_number%4];
delay(millis_delay);
if(stepperMotor.direction== MOTOR_ANTICLOCKWISE)
{
step_number++;
if (step_number == number_of_steps)
step_number = 0;
}
else
{
step_number--;
if (step_number == 0)
step_number = number_of_steps;
}
steps_left --;
}
}
void initialize()
{
pinMode(MOTORSHIELD_IN1,OUTPUT);
pinMode(MOTORSHIELD_IN2,OUTPUT);
pinMode(MOTORSHIELD_IN3,OUTPUT);
pinMode(MOTORSHIELD_IN4,OUTPUT);
pinMode(CTRLPIN_A,OUTPUT);
pinMode(CTRLPIN_B,OUTPUT);
stop();
stepperMotor.speed = 1;
stepperMotor.direction = MOTOR_CLOCKWISE;
}
/*******************************************/
void stop()
{
/*Unenble the pin, to stop the motor. */
digitalWrite(CTRLPIN_A,LOW);
digitalWrite(CTRLPIN_B,LOW);
}
void setup()
{
initialize();//Initialization for the stepper motor.
}
void loop()
{
step(200);//Stepper motors rotate anticlockwise 200 steps.
delay(1000);
step(-200);//Stepper motors rotate clockwise 200 steps.
delay(1000);
}
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