I2C Sensors that can be combined on a small board

I discovered that there are several tiny sensors that can be combined together in a single pcb board. This is cool because these sensors requires only 2 pins which means you can add more devices when more pins are available. The scarcity of pins is a common problem of newbie electronic hobbyists. The other most common problem is the availability of space, the more the device that is connected requires bigger pcb, and the device can be as big as a normal personal computer already which does not makes sense if you want to carry your diy device around. And the coolest thing about these sensors is that they have very similar circuit implementation. So if you have read my previous about the Digital Compass, then it should not be hard for you to implement the other sensors.

My previous post used HMC5883L which is a low cost 3-axis Digital Compass. Aside from showing where you are facing, this is device can be used to control the direction of rotation of a motor without pressing a button.

If your goal is to create a device that can give you information like the current temperature, pressure and how high your location or how fast you are moving upward or downward then you need a BMP180 Digital Pressure Sensor. This is commonly used in rocketry or even in drones. It is also commonly used by explorers and mountaineers.

Another sensor that has many applications and can tell so much about your movement such as angle of inclination, how fast you are spinning and can tell you your orientation and this is the MPU6050, a MEMs 3-axix gyroscope and 3-axis accelerometer at the same time.

All three sensors(BMP180, HMC5883L and MPU6050) can be combined is a tiny pcb board with very minimal passive components. Here is the module:

Digital Compass during Sunday Midnight

I could not sleep last night so I kept myself busy by creating a simple breakout board of HMC5883L which is a low cost 3-axis Digital Compass. I thought it would keep me busy the whole night until the morning but I was wrong, it only took me less than an hour to finish the job.

Here's some picture of what I have done:
1. The 3D render from Kicad:

2. The back panel of the pcb. This image was produced upon submission to the fab:

3. The front panel of the pcb. This image was also produced upon submission to the fab:

 4. The pcb view from Kicad:

5. And finally the schematic diagram:

Sparkfun has similar breakout board and some features listed in their website is as follows:

• Simple I2C interface
• 2.16-3.6VDC supply range
• Low current draw
• 5 milli-gauss resolution

I did copied their breakout board but coincedintally, probably we have the same source, the ic's datasheet. I just followed  the Single Supply Reference Design provided in the datasheet.

Transferring my Digital Clock from Breadboard to a PCB

I had fun learning KiCAD last weekend. After 2 days of fun learning, I thought I should transfer my digital clock project to a nice pcb. I asked myself why do I need a gorgeous pcb? And here are the answers to my questions:

1. I want to get rid of the mess on my work table.

2. The hardware can be temporarily freeze to its current version. I still have plans of adding more features on the hardware side.
3. I want to check how it will look like in a professionaly designed and fabricated pcb.
4. I want to concentrate in creating a better firmware.

With the above mentioned reasons, I was able to convinced and motivate myself to create the pcb. As of today, I am done with the initial design and here is the initial render:

Back View:

Front View:

The pcb I created is basically an arduino uno shield that can be used as a tool for learning and getting familiarized with the programming language of arduino. This really perfect for beginners and can still be appreciated by  the experts.

The Clock is Simple No More

Well it is really awesome to say that the clock is no longer that simple because I added a few more features to make it a nice clock, it is not yet the final version because I have tons of ideas to make a one hell of a device which I can call one of my best projects ever!

The New Features
 I've added 3 new features which are as follows:
1. 2 new buttons to control the brightness. This is just a temporary version, I just want to check whether it is nice to have a button and to control the brightness. It turns out that yes, it is indeed needed. I still am thinking  if I will make this permanent because I plan to control the brightness, contrast, set time and date, store important dates and alarms using the pc. I connected the 2 buttons using the schematic below:

2. A back-up battery with Charger and DC-DC Step Up converter. The clock will not be connected to the pc 90% of the time so a battery is needed to power it up and must be rechargeable just like cellphone. I used the AREF pin to bypass the on board  regulator of the arduino because it is not efficient. The battery is rated 3.6V so it is not enough to power-up the arduino that is why I need to bost that voltage to 5V using the DC-DC Step-up converter. Below is the connection diagram I used:

3. A software feature to monitor the battery charge. Using the diagram above, I connected A1(analog pin 1) of the arduino to the positive terminal of the battery to measure current charge of the battery. I used the following codes:

    val3 = val3 + analogRead(1);
    charglim++;
    if(charglim>40)
    {
    val3 = val3/charglim; 

    val1 = val3/204.6; //0-5V

    charglim = 0;
    val3 = 0;  
  }

analogRead(1) will return values between 0 to 1023 which is summed up to val3 40 times and the average is taken and converted to voltage reading.

Here's the actual pictures of the components I used:

Some of the components I used can be bought from my sulit shop http://n92seller.sulit.com.ph

The Simple Clock just got an upgrade!

Having a digital clock that is active the whole day does not only consumes a lot of electricity but might damage the lcd in the short term so I thought I should add another feature to automatically turn off the lcd. This clock is meant to sit on a desktop so I will be too lazy to push  a button just to check the time. A perfect solution to this is to add an Ultrasonic sensor module. With this device connected to an Arduino, all I have to do is to place my hand at least 40cms away from it and it turns on the lcd automatically.

Here is how I connected the ultrasonic sensor to the Aceduino:

There are quite a few sample sketches on the web how to make the ultrasonic sensor work and based on my experience, I was able to make it work in just a about 5 mins because all I have to do is cut and paste the code and added an indicator at the buttom of the lcd to show the current measurement being made by the sensor.

To turn on-off the lcd via code is very simple, it is just an if-then-else statement and setting all digital pins used by the lcd to input to turn it off and output to turn it on.

Here is the sample video of the working digital clock:



And finally here is the sketch I used:

#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>
#include "Wire.h"

#define DS1307_ADDRESS 0x68
byte zero = 0x00; //workaround for issue #527
// pin 7 - Serial clock out (SCLK)3
// pin 6 - Serial data out (DIN)4
// pin 5 - Data/Command select (D/C)5
// pin 4 - LCD chip select (CS)7
// pin 3 - LCD reset (RST)6
Adafruit_PCD8544 display = Adafruit_PCD8544(3, 4, 5, 7, 6);
#define echoPin 8 // Echo Pin
#define trigPin 9 // Trigger Pin
#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2
float i;
float ii;
float yy;
int xk;
int xl;
  int second1;
  int minute1;
  int hour1; //24 hour time
  int weekDay1; //0-6 -> sunday - Saturday
  int monthDay1;
  int month1;
  int year1;
#define LOGO16_GLCD_HEIGHT 16
#define LOGO16_GLCD_WIDTH  16

long duration, distance; // Duration used to calculate distance
long distance1;
void setup()   {
    Wire.begin();
  Serial.begin(9600);
  pinMode(10, OUTPUT);
  analogWrite(10, 950);
  display.begin();
  display.clearDisplay();
  display.setContrast(45);
//Ultrasonic sensor settings
   pinMode(trigPin, OUTPUT);
   pinMode(echoPin, INPUT);

//setDateTime();
}

void loop() {
//  analogWrite(10, ii);

 digitalWrite(trigPin, LOW);
// delayMicroseconds(1);

 digitalWrite(trigPin, HIGH);
// delayMicroseconds(5);

 digitalWrite(trigPin, LOW);
 duration = pulseIn(echoPin, HIGH);

 //Calculate the distance (in cm) based on the speed of sound.
 distance = duration/58.2;

  printDate();
i = i + 0.05;
if(xk==1)
{
yy = (sin(i) * 4) + 34;
    display.drawPixel(i*2.95, yy, WHITE);
yy = (sin(i*-1) * 4) + 34;
    display.drawPixel(i*2.95, yy, WHITE);
}
else
{
yy = (sin(i) * 4) + 34;
    display.drawPixel(i*2.95, yy, BLACK);
yy = (sin(i*-1) * 4) + 34;
    display.drawPixel(i*2.95, yy, BLACK); 
}
  display.display();
  delay(50);
 
 if(i>33){
  ii++ ; 
  i=0;
  //display.clearDisplay();
   second1=0;
   minute1=0;
   hour1=0;
   weekDay1=0;
   monthDay1=0;
   month1=0;
   year1=0;
   if(xk==1)
   {
     xk = 0;
   }
   else
   {
    xk=1;
   } 
 }

 if(ii>1){
 xl = 1;
 pinMode(10, INPUT); //turns off the backlight

// turns off the lcd
 display.setContrast(0);
    pinMode(3, INPUT);
    pinMode(4, INPUT);
    pinMode(5, INPUT);
    pinMode(5, INPUT);
    pinMode(7, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  ii=0;
 }

  if((distance<40) and (xl==1)){//turns on the lcd
xl = 0;
ii=0;
 pinMode(10, OUTPUT);//turns on the back light

// power_twi_enable();
    pinMode(3, OUTPUT);
    pinMode(4, OUTPUT);
    pinMode(5, OUTPUT);
    pinMode(5, OUTPUT);
    pinMode(7, OUTPUT);
display.setContrast(45);
 }
}
void setDateTime(){

  byte second =      15; //0-59
  byte minute =      00; //0-59
  byte hour =        16; //0-23
  byte weekDay =     2; //1-7
  byte monthDay =    26; //1-31
  byte month =       11; //1-12
  byte year  =       13; //0-99

  Wire.beginTransmission(DS1307_ADDRESS);
  Wire.write(zero); //stop Oscillator

  Wire.write(decToBcd(second));
  Wire.write(decToBcd(minute));
  Wire.write(decToBcd(hour));
  Wire.write(decToBcd(weekDay));
  Wire.write(decToBcd(monthDay));
  Wire.write(decToBcd(month));
  Wire.write(decToBcd(year));

  Wire.write(zero); //start

  Wire.endTransmission();

}

byte decToBcd(byte val){
// Convert normal decimal numbers to binary coded decimal
  return ( (val/10*16) + (val%10) );
}

byte bcdToDec(byte val)  {
// Convert binary coded decimal to normal decimal numbers
  return ( (val/16*10) + (val%16) );
}

void printDate(){

  // Reset the register pointer
  Wire.beginTransmission(DS1307_ADDRESS);
  Wire.write(zero);
  Wire.endTransmission();

  Wire.requestFrom(DS1307_ADDRESS, 7);

  int second = bcdToDec(Wire.read());
  int minute = bcdToDec(Wire.read());
  int hour = bcdToDec(Wire.read() & 0b111111); //24 hour time
  int weekDay = bcdToDec(Wire.read()); //0-6 -> sunday - Saturday
  int monthDay = bcdToDec(Wire.read());
  int month = bcdToDec(Wire.read());
  int year = bcdToDec(Wire.read());
 
  display.setTextSize(1);


     if(month!=month1)
  {
  display.setCursor(10,0); 
  display.setTextColor(WHITE);
   display.print(month1);
  display.setCursor(10,0); 
    if((month<=10) and (month>0))
  {
    display.print("0");
  }    
  display.print(month1);
    display.setCursor(10,0);
  display.setTextColor(BLACK);
    if(month<10)
  {
    display.print("0");
  }
  display.print(month);
 
  month1 = month;
   }       

 
 

   display.setCursor(26,0);
  display.print("/");
 

     if(monthDay!=monthDay1)
  {
  display.setCursor(34,0); 
  display.setTextColor(WHITE);
   display.print(monthDay1);
  display.setCursor(34,0); 
    if((monthDay<=10) and (monthDay>0))
  {
    display.print("0");
  }    
  display.print(monthDay1);
    display.setCursor(34,0);
  display.setTextColor(BLACK);
    if(monthDay<10)
  {
    display.print("0");
  }      
  display.print(monthDay);
  monthDay1 = monthDay;
   }       

   display.setCursor(50,0);
  display.print("/");
 

    if(year!=year1)
  {
  display.setCursor(58,0); 
  display.setTextColor(WHITE);
   display.print(year1);
  display.setCursor(58,0); 
    if((year<=10) and (year>0))
  {
    display.print("0");
  }  
  display.print(year1);
    display.setCursor(58,0);
  display.setTextColor(BLACK);
     if(year<10)
  {
    display.print("0");
  }    
  display.print(year);
  year1 = year;
   }      

display.setTextSize(2);
    if(hour!=hour1)
  {
  display.setCursor(0,12); 
  display.setTextColor(WHITE);
    display.print(hour1);
  display.setCursor(0,12); 
    if((hour<=10) and (hour>0))
  {
    display.print("0");
  }  
  display.print(hour1);
    display.setCursor(0,12);
  display.setTextColor(BLACK);
     if(hour<10)
  {
    display.print("0");
  }  
  display.print(hour);
  hour1 = hour;
   }    

   display.setCursor(21,12);
  display.print(":");
 

    if(minute!=minute1)
  {
  display.setCursor(31,12); 
  display.setTextColor(WHITE);
    display.print(minute1);
  display.setCursor(31,12); 
    if((minute<=10) and (minute>0))
  {
    display.print("0");
  }
  display.print(minute1);
    display.setCursor(31,12);
  display.setTextColor(BLACK);
      if(minute<10)
  {
    display.print("0");
  }
  display.print(minute);
  minute1 = minute;
   }  

   display.setCursor(52,12);
  display.print(":");

  
  if(second!=second1)
  {
  display.setCursor(60,12); 
  display.setTextColor(WHITE);
  display.print(second1);
  display.setCursor(60,12); 
    if((second<=10) and (second>0))
  {
    display.print("0");
  }
  display.print(second1);
    display.setCursor(60,12);
  display.setTextColor(BLACK);
    if(second<10)
  {
    display.print("0");
  }
  display.print(second);
  second1 = second;
   }  
   display.setTextSize(1);
    if(distance!=distance1)
  {
  display.setCursor(34,40); 
  display.setTextColor(WHITE);
   display.print(distance1);
  display.setCursor(34,40); 
    if((distance<=10) and (distance>0))
  {
    display.print("0");
  }    
  display.print(distance1);
    display.setCursor(34,40);
  display.setTextColor(BLACK);
    if(distance<10)
  {
    display.print("0");
  }
  display.print(distance);
 
  distance1 = distance;
   }     

}

A Simple Clock using Nokia 5110 LCD Module

It is a lazy Monday morning and while daydreaming, I came up with an idea of creating a simple digital clock. I know it is simple because I have the components needed to create it.

The components needed for this simple project is as follows:
1. Nokia LCD Module
2. Aceduino Uno
3. RTC(real time clock) DS1307 Module
4. 12 male-female dupont wires

On the software side I will be using the following:
1. Arduino programming software
2. Adafruit Nokia 5110 Graphics Library

Connecting the components together is very easy and can be done in about 2 minutes.

RTC Module uses the I2C communication Protocol while the Nokia Lcd Module needs 6 digital pins to make it work and no standard communication protocol is needed to make it work.  See the following connection diagrams how the 2 modules should be connected to Arduino.

I used Adafruit's Grpahics Library to generate the small and big numbers and the animated sine wave at the buttom. Adafruit's Graphics Library contains almost all the necessary features needed but I noticed that the library is not capable of controlling the brightness of the backlight so I cleverly invented my own way of controlling it.

I did it by connecting the Light pin of the lcd module to PWM pin 10 of the Aceduino Uno. And here are some commands needed to control the back light:

1. pinMode(10, OUTPUT); - turns on the back light
2. pinMode(10, INPUT); - turns off the back light
3. analogWrite(10, X); - control the brightness(X can be from 0 to 1023 and 0 being the brightest)

Here is the video of the digital clock:

Here is the rest of the sketch I used:

#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>
#include "Wire.h"
#define DS1307_ADDRESS 0x68
byte zero = 0x00; //workaround for issue #527
// pin 7 - Serial clock out (SCLK)3
// pin 6 - Serial data out (DIN)4
// pin 5 - Data/Command select (D/C)5
// pin 4 - LCD chip select (CS)7
// pin 3 - LCD reset (RST)6
Adafruit_PCD8544 display = Adafruit_PCD8544(3, 4, 5, 7, 6);

#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2
float i;
float ii;
float yy;
int xk;
  int second1;
  int minute1;
  int hour1; //24 hour time
  int weekDay1; //0-6 -> sunday - Saturday
  int monthDay1;
  int month1;
  int year1;
#define LOGO16_GLCD_HEIGHT 16
#define LOGO16_GLCD_WIDTH  16
void setup()   {
    Wire.begin();
  Serial.begin(9600);
  pinMode(10, OUTPUT);
  analogWrite(10, 950);
  display.begin();
  display.clearDisplay();
  display.setContrast(45);
//setDateTime();
}

void loop() {
//  analogWrite(10, ii);
// ii++ ;
  printDate();
i = i + 0.05;
if(xk==1)
{
yy = (sin(i) * 5) + 37;
    display.drawPixel(i*2.95, yy, WHITE);
yy = (sin(i*-1) * 5) + 37;
    display.drawPixel(i*2.95, yy, WHITE);
}
else
{
yy = (sin(i) * 5) + 37;
    display.drawPixel(i*2.95, yy, BLACK);
yy = (sin(i*-1) * 5) + 37;
    display.drawPixel(i*2.95, yy, BLACK); 
}
  display.display();
  delay(50);
 
 if(i>33){
  i=0;
  //display.clearDisplay();
   second1=0;
   minute1=0;
   hour1=0;
   weekDay1=0;
   monthDay1=0;
   month1=0;
   year1=0;
   if(xk==1)
   {
     xk = 0;
   }
   else
   {
    xk=1;
   } 
 }

// if(ii>1023){
//  ii=0;

// }
}
void setDateTime(){

  byte second =      45; //0-59
  byte minute =      04; //0-59
  byte hour =        20; //0-23
  byte weekDay =     1; //1-7
  byte monthDay =    25; //1-31
  byte month =       11; //1-12
  byte year  =       13; //0-99

  Wire.beginTransmission(DS1307_ADDRESS);
  Wire.write(zero); //stop Oscillator

  Wire.write(decToBcd(second));
  Wire.write(decToBcd(minute));
  Wire.write(decToBcd(hour));
  Wire.write(decToBcd(weekDay));
  Wire.write(decToBcd(monthDay));
  Wire.write(decToBcd(month));
  Wire.write(decToBcd(year));

  Wire.write(zero); //start

  Wire.endTransmission();

}

byte decToBcd(byte val){
// Convert normal decimal numbers to binary coded decimal
  return ( (val/10*16) + (val%10) );
}

byte bcdToDec(byte val)  {
// Convert binary coded decimal to normal decimal numbers
  return ( (val/16*10) + (val%16) );
}

void printDate(){

  // Reset the register pointer
  Wire.beginTransmission(DS1307_ADDRESS);
  Wire.write(zero);
  Wire.endTransmission();

  Wire.requestFrom(DS1307_ADDRESS, 7);

  int second = bcdToDec(Wire.read());
  int minute = bcdToDec(Wire.read());
  int hour = bcdToDec(Wire.read() & 0b111111); //24 hour time
  int weekDay = bcdToDec(Wire.read()); //0-6 -> sunday - Saturday
  int monthDay = bcdToDec(Wire.read());
  int month = bcdToDec(Wire.read());
  int year = bcdToDec(Wire.read());
 
  display.setTextSize(1);


     if(month!=month1)
  {
  display.setCursor(10,0); 
  display.setTextColor(WHITE);
   display.print(month1);
  display.setCursor(10,0); 
    if((month<=10) and (month>0))
  {
    display.print("0");
  }    
  display.print(month1);
    display.setCursor(10,0);
  display.setTextColor(BLACK);
    if(month<10)
  {
    display.print("0");
  }
  display.print(month);
 
  month1 = month;
   }       

 
 

   display.setCursor(26,0);
  display.print("/");
 

     if(monthDay!=monthDay1)
  {
  display.setCursor(34,0); 
  display.setTextColor(WHITE);
   display.print(monthDay1);
  display.setCursor(34,0); 
    if((monthDay<=10) and (monthDay>0))
  {
    display.print("0");
  }    
  display.print(monthDay1);
    display.setCursor(34,0);
  display.setTextColor(BLACK);
    if(monthDay<10)
  {
    display.print("0");
  }      
  display.print(monthDay);
  monthDay1 = monthDay;
   }       

   display.setCursor(50,0);
  display.print("/");
 

    if(year!=year1)
  {
  display.setCursor(58,0); 
  display.setTextColor(WHITE);
   display.print(year1);
  display.setCursor(58,0); 
    if((year<=10) and (year>0))
  {
    display.print("0");
  }  
  display.print(year1);
    display.setCursor(58,0);
  display.setTextColor(BLACK);
     if(year<10)
  {
    display.print("0");
  }    
  display.print(year);
  year1 = year;
   }      

display.setTextSize(2);
    if(hour!=hour1)
  {
  display.setCursor(0,12); 
  display.setTextColor(WHITE);
    display.print(hour1);
  display.setCursor(0,12); 
    if((hour<=10) and (hour>0))
  {
    display.print("0");
  }  
  display.print(hour1);
    display.setCursor(0,12);
  display.setTextColor(BLACK);
     if(hour<10)
  {
    display.print("0");
  }  
  display.print(hour);
  hour1 = hour;
   }    

   display.setCursor(21,12);
  display.print(":");
 

    if(minute!=minute1)
  {
  display.setCursor(31,12); 
  display.setTextColor(WHITE);
    display.print(minute1);
  display.setCursor(31,12); 
    if((minute<=10) and (minute>0))
  {
    display.print("0");
  }
  display.print(minute1);
    display.setCursor(31,12);
  display.setTextColor(BLACK);
      if(minute<10)
  {
    display.print("0");
  }
  display.print(minute);
  minute1 = minute;
   }  

   display.setCursor(52,12);
  display.print(":");

  
  if(second!=second1)
  {
  display.setCursor(60,12); 
  display.setTextColor(WHITE);
  display.print(second1);
  display.setCursor(60,12); 
    if((second<=10) and (second>0))
  {
    display.print("0");
  }
  display.print(second1);
    display.setCursor(60,12);
  display.setTextColor(BLACK);
    if(second<10)
  {
    display.print("0");
  }
  display.print(second);
  second1 = second;
   }  


}

Portable Charger with Battery Bank Revisited

5 months ago, when I first posted my project, the portable charger with battery bank, I wrote that I am still waiting for the arrival of  4 pcs lithium ion batteries and will be looking for a transparent enclosure so that the battery charge indicator will be exposed. Unfortunately, my batteries did not arrived and had to cancel my order and could not find a nice trasnparent enclosure.

3 weeks ago, I tried to find a similar battery but I also failed so I settled for 4 pcs 900mAH 1.2V lithium ion rechargeable AA batteries. This is way below the original specs but the price is also cheap because each battery cost Php60 only. I will use this batteries just to offset the waiting period for the arrival of my newly ordered  high capacity batteries. I also plan to upgrade my exisitng DC-DC Step up module from 500mAmp output to 1.5mAmp output.

I had been playing with it for a week now and surprisingly all of my tests yielded unexpected results. The current specs is as follows:
1) 5V 1Amp Input derrived from the USB Charging module
2) Battery Bank capacity is 3600mAH. 2pcs connected in series and resulting in 2 pcs of 1800mAH 2.4V and connected them in parallel.
3) 5V 500mAmp output.

I don't expect much juice from that configuration since it's a low-voltage configuration which translates to a much lower mAH in reality.

 Here is the resulting device:

I used electrical tape to hold all 3 pcs together(the batteries, charging module and dc-dc usb step up module) and to hide all the wires in between.

Here are some results of my experiments:
1. Charging time is at least 4hours. 4.2V can never be achieved since the battery bank is only 2.4V as a result the red led in the mini usd charging module will never light up. The red led will light up if a 3.7V battery is fully charged at 4.2V.

2. When fully charged, it can be a temporary power source of an Ipad mini or any Android Tablet for 30 to 45 minutes but could not charge it. This surpassed my expectation since the output is only 500mAmps while the Ipad Mini requires at least 1Amp.

3. It can power up a 12V 0.15Amp dc brushless motor for 30 minutes. I used the 5W DC DC 5-12V Step Module.