A Mass Programming Bench for ATMega32u4 MCUs

“limpkin” @ limpkin.fr wanted to program some thousand of MCUs so he decided to build his own programming bench. He writes:

As you may know I started the Mooltipass offline password keeper project more than 2 years ago. Together with a team of volunteers from all over the globe I created two Mooltipass devices which were successfully crowdfunded through Indiegogo and Kickstarter, raising a total of around $290k.
Through a secure mechanism it is possible to upgrade the firmware running on the Mooltipass units. On our latest device, the Mooltipass Mini, we implemented signed firmware updates, which involved storing inside the microcontrollers’ memory some cryptographic keys.

A Mass Programming Bench for ATMega32u4 MCUs – [Link]

Tibbo – New Tutorial List

Tibbo has a new list of tutorials on their website. Check them out:

  1. Quick jump to start NodeJS development on LTPS boards http://tibbo.com/linux/nodejs/before-you-begin.html
  2. LED Control From the Web Browser http://tibbo.com/linux/nodejs/led-control-from-browser.html
  3. Two-way Control with Web and Button http://tibbo.com/linux/nodejs/two-way-control-web-button.html
  4. Simple Card-based Access Control http://tibbo.com/linux/nodejs/simple-card-based-access-control.html
  5. GPIO: Displaying currency exchange rate on 7-segment indicators http://tibbo.com/linux/nodejs/gpio-seven-segment-indicators.html
  6. Tracking Environmental Data with TPS and Keen.IO http://tibbo.com/linux/nodejs/tracking-environmental-data.html
  7. Complex Build: Redis for LTPS http://tibbo.com/linux/native-c/building-redis.html

GPS RECEIVER TO FM RADIO (88-107 MHz) AUDIO + RDS TRACKING V2

Today I made some modifications to this is a new project for a GPS to FM radio tracking device for rockets i.e. the V2. The initial design lacked the antenna impedance matching circuit which caused problems with the end amplifier. Also I increased the possible choices of frequencies, see the table further down. Now instead of soldering and de-soldering tiny resistors, the frequency and the transmitting modes are selected via a DIP switch.

GPS RECEIVER TO FM RADIO (88-107 MHz) AUDIO + RDS TRACKING V2 – [Link]

MyPart, An Open Source Portable Air Particle Counter

One of the most harmful airborne pollutants with respect to human health is particulate matter. Air particle counters are used to determine the air quality by counting and sizing the number of particles in the air. This information is useful in determining the amount of particles inside a building or in the ambient air. It is also useful in understanding the cleanliness level in a controlled environment.

Airborne particles with a diameter of less than 10 microns pose a large risk, they can travel deeply into the respiratory system, causing a variety of cardiovascular and respiratory diseases. Combustion (e.g. burning wood; automobiles) can generate particles less than 2.5 microns in diameter. Between 2.5 and 10 microns are particles such as dust, pollen, and mold. (More information about particulate matter can be found here.)

Four members of the Hybrid Ecologies Lab at UC Berkeley, Rundong Tian, Sarah Sterman, Chris Myers, and Eric Paulos, developed “MyPart”, a device that attempts to measure air particulate matter.

MyPart’s design focuses on four goals; accuracy, size and portability, cost, and open source.

Accuracy

In the test chamber, smoke concentration was allowed to decay naturally over about 2 hours. Three prototypes of MyPart gave similar accuracy results to an expensive instrument results ($5000 MetOne HHPC-6).

Additional experiments conducted with calibration particles of known sizes and in outdoor ambient environments, and more information about the tests can be found here.

Size & Portability

The overall size of the inner sensing chamber is 18mmx38mmx45mm. These dimensions include an onboard 400mAh battery. The components related to the sensing are completely separated from the outer casing, which allows various form factors to easily be explored, developed, and shared.

MyPart sensor consumes about 2 mA while sleeping, and about 70mA during sampling.

Cost

The total cost for the bill of materials is around $75 without the cost of the digital fabrication tools required to make the components (3D printer and CNC mill). This BOM prices are for electrical components in quantities of 1 or 2, which will drop dramatically when purchased in bulk.

Open Source

MyPart’s original design files and source codes are all open source in order to give people the base form which to make and modify their own sensors, to set up sensing in their own communities, and to generate reliable air quality data.

The full BOM can be found here. The fabrication files, as well as the original design files can be found here.

MyPart’s Parts

  • Top air channel, Contains the main flow channel, a light trap for the laser light, and the air inlet.
  • Bottom air channel, Contains features to hold the fan, and the air outlet
  • Analog cap, shields the sensitive analog circuitry from ambient light
  • Fan, pulls air through the channel
  • Laser, focused light source to illuminate particles in the airstream
  • Laser holder, aligns the laser to the photodiode

Limitations

Optical scattering: The quantity and direction of light scattered by a particle is dependent on the size, composition, and shape of the particle, as well as where it strikes the laser beam. Because of these factors, accurate sizing of particles tends to be difficult with optical scattering sensors. However, rough size cutoff bins can still be produced by using the amplitude of signal peaks.

Full documentation, technical details, and how to build guide are reachable at this seeedstudio article and this instructable.

AC Motor Speed Controller for Modern Appliances Using LS7311

The project specifically designed for motor speed control application in appliances such as blenders, etc. Tact switches provided for selecting/indicating from 1 to 10 power levels ( Speed Levels).  The project is ideal for universal and shaded-pole motor speed control for modern appliances design. Eliminates awkward mechanical switch assemblies and multi-taped motor winding.

Features

  • 10 Tact Switch for Speed Selection
  • 10 LEDS for speed indication
  • On Board Stop and Start Switches ( Start Switch Latch Operation)
  • Momentary Run Switch
  • Supply 230V ( 110V Possible Refer Data sheet for components Change)
  • 300W Load
  • On Board snubber for Inductive Load
  • No Separate DC power supply required

AC Motor Speed Controller for Modern Appliances Using LS7311 – [Link]

TP4056 3V3 Load Share Upgrade

A lot of project are battery powered and some of them need dual battery links. Robert on hackaday.io had shared his new project that shed light on this issue. He built an load sharing addon board with the ability to charge the battery while the project is operating.

Many Chinese charger boards are out there based on TP4056, but these boards don’t have the load sharing or voltage regulator features.

Load sharing means that you can power your circuit in two ways, from battery and from Vcc if a charger is connected. Once the charger is connected the battery will start charging and the load will be powered directly from Vcc. Robert added this feature to a recent design and also he added voltage regulation by using MCP1252.

The Components needed to build this project:

  • 1x  MCP1252-33X50/MS Power: Management IC / Switching Regulators
  • 1x  FDN304P: Discrete Semiconductors / Diode-Transistor Modules
  • 1x  SGL1-40-DIO: Schottky diode
  • 2x  100k 1206 resistor
  • 3x  10uF 1206 capacitor X7R
  • 1x  2.2uF 0805 capacitor X7R
  • 1x  ON/OFF switch (optional)
  • 2x  2 pin pcb connector
  • 1x  PCB from OSHpark

This schematic was inspired by multiple designs and modified by Robert.

“The advantage of MCP1252 is automatic buck/boost feature, it will maintain the regulated output voltage whether the input voltage is above or below the output voltage (2.1 to 5.0 V input range) so it is ideal for the lithium battery voltage. If you read the datasheet for the MCP1252-33X50I/MS there is clearly specified what type of MLCC capacitor should be used.”

The maximum output current of this board is 120mA and the output voltage is 3.3 V. It may sound not that suitable for your projects if you want to power an ESP8266, but still you can build your own board with different components to achieve the outputs you need. For example, by using MCP1253, which is identical to MCP1252, you will get  higher switching frequency (1MHz). Robert’s plan is to use this board with CO2 sensor (about 30 mA) and other low power sensors, some MCU and LCD, which can be powered using 120 mA.

Some measurements will be done to test the functionality of this board. To keep updated with the news of this project, you can follow the project on hackaday.io. You can also check other projects by Robert here.

ZeroPhone – a Raspberry Pi smartphone

Arsenijs build a Pi-powered open-source mobile phone (that you can assemble for 50$ in parts).

Currently, it costs about 50$ in parts, and all the parts are available on eBay. No BGA or other difficultly solderable ICs are used (with the obvious exception of Pi Zero). User interface is written using Python, and there’s a phone-tailored UI framework in the works (so far, it uses pyLCI for interfacing). However, even current state of it is further that other projects have come.

ZeroPhone – a Raspberry Pi smartphone – [Link]

Thermometer That Pushes Arduino to Its Limits

by gundolf @ instructables.com:

Starting playing with Arduino seems simple enough. You can find all sorts of tutorials, instructables, wiring and code examples for pretty much every sensor, component, or module available. So far so good. But when the time comes for building a more complex device, the troubles start. The tutorials for adding multiple modules to Arduino and then working with them efficiently are very scarce. Therefore, with this instructable, I will try to help with just that. So here comes the Arduino thermometer/hygrometer with a GUI, designed to push Arduino to its limits.

Thermometer That Pushes Arduino to Its Limits – [Link]

Alarm System Powered By Arduino

Dejan Nedelkovski had built an Arduino security and alarm system project that uses an ultrasonic sensor for detecting objects and a buzzer for notification.

Components needed to build this simple system are: Arduino board, LCD display, 4×4 keypad, ultrasonic sensor and buzzer. The circuit can be connected as shown in the schematics below.

In order to build the project, you have to connect the buzzer with a PWM pin and the keypad pins where 4 of the 8 pins are for rows and the rest are for columns.

“The 4×4 keypad has 8 pins, 4 of them are for the rows and 4 of them for the columns of the keypad. Each button is actually a push button switch which makes a short between one row and column when pressed. So, for example, if we set the row 1 line low, and all column lines high, when we will press, for example, the button 3, due to the short between the two lines, the column 3 line will drop to low so in such a case we can register that the button 3 has been pressed.”

For connecting the LCD display and ultrasonic sensor you can check this detailed video tutorial by Dejan Nedelkovski and to see the project in action:

We want to activate the alarm by setting the A button to activate it. B button is used to change the password, and you need to enter the preset password “1234” to be able to change it.
After activating the alarm by pressing A, a 200 milliseconds sound will be produced from the buzzer showing that the alarm is now active. A message on the LCD display will appear to saying “Alarm will be activated in” and a countdown will be running afterwards until the alarm is completely active. At the end of the countdown a ” Alarm Activated” is on the display and the sensor will start working. Comparing with the initial distance at the start, the sensor will measure the distance is smaller than the initial distance, corrected by a value of 10 cms. The buzzer will  produce a sound if an object is observed as per the condition.

Here’s the complete source code of the Arduino alarm system:

/*
* Arduino Security and Alarm System
*
* by Dejan Nedelkovski,
* www.HowToMechatronics.com
*
*/
#include <LiquidCrystal.h> // includes the LiquidCrystal Library 
#include <Keypad.h>
#define buzzer 8
#define trigPin 9
#define echoPin 10
long duration;
int distance, initialDistance, currentDistance, i;
int screenOffMsg =0;
String password="1234";
String tempPassword;
boolean activated = false; // State of the alarm
boolean isActivated;
boolean activateAlarm = false;
boolean alarmActivated = false;
boolean enteredPassword; // State of the entered password to stop the alarm
boolean passChangeMode = false;
boolean passChanged = false;
const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
char keypressed;
//define the cymbols on the buttons of the keypads
char keyMap[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {14, 15, 16, 17}; //Row pinouts of the keypad
byte colPins[COLS] = {18, 19, 20, 21}; //Column pinouts of the keypad
Keypad myKeypad = Keypad( makeKeymap(keyMap), rowPins, colPins, ROWS, COLS); 
LiquidCrystal lcd(1, 2, 4, 5, 6, 7); // Creates an LC object. Parameters: (rs, enable, d4, d5, d6, d7) 
void setup() { 
  lcd.begin(16,2); 
  pinMode(buzzer, OUTPUT); // Set buzzer as an output
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
}
void loop() {
  if (activateAlarm) {
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Alarm will be");
    lcd.setCursor(0,1);
    lcd.print("activated in");
   
    int countdown = 9; // 9 seconds count down before activating the alarm
    while (countdown != 0) {
      lcd.setCursor(13,1);
      lcd.print(countdown);
      countdown--;
      tone(buzzer, 700, 100);
      delay(1000);
    }
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Alarm Activated!");
    initialDistance = getDistance();
    activateAlarm = false;
    alarmActivated = true;
  }
  if (alarmActivated == true){
      currentDistance = getDistance() + 10;
      if ( currentDistance < initialDistance) {
        tone(buzzer, 1000); // Send 1KHz sound signal 
        lcd.clear();
        enterPassword();
      }
    }
  if (!alarmActivated) {
    if (screenOffMsg == 0 ){
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("A - Activate");
      lcd.setCursor(0,1);
      lcd.print("B - Change Pass");
      screenOffMsg = 1;
    }
    keypressed = myKeypad.getKey();
     if (keypressed =='A'){        //If A is pressed, activate the alarm
      tone(buzzer, 1000, 200);
      activateAlarm = true;            
    }
    else if (keypressed =='B') {
      lcd.clear();
      int i=1;
      tone(buzzer, 2000, 100);
      tempPassword = "";
      lcd.setCursor(0,0);
      lcd.print("Current Password");
      lcd.setCursor(0,1);
      lcd.print(">");
      passChangeMode = true;
      passChanged = true;   
      while(passChanged) {      
      keypressed = myKeypad.getKey();
      if (keypressed != NO_KEY){
        if (keypressed == '0' || keypressed == '1' || keypressed == '2' || keypressed == '3' ||
            keypressed == '4' || keypressed == '5' || keypressed == '6' || keypressed == '7' ||
            keypressed == '8' || keypressed == '9' ) {
         tempPassword += keypressed;
         lcd.setCursor(i,1);
         lcd.print("*");
         i++;
         tone(buzzer, 2000, 100);
        }
      }
      if (i > 5 || keypressed == '#') {
        tempPassword = "";
        i=1;
        lcd.clear();
        lcd.setCursor(0,0);
        lcd.print("Current Password");
        lcd.setCursor(0,1);
        lcd.print(">"); 
      }
      if ( keypressed == '*') {
        i=1;
        tone(buzzer, 2000, 100);
        if (password == tempPassword) {
          tempPassword="";
          lcd.clear();
          lcd.setCursor(0,0);
          lcd.print("Set New Password");
          lcd.setCursor(0,1);
          lcd.print(">");
          while(passChangeMode) {
            keypressed = myKeypad.getKey();
            if (keypressed != NO_KEY){
              if (keypressed == '0' || keypressed == '1' || keypressed == '2' || keypressed == '3' ||
                  keypressed == '4' || keypressed == '5' || keypressed == '6' || keypressed == '7' ||
                  keypressed == '8' || keypressed == '9' ) {
                tempPassword += keypressed;
                lcd.setCursor(i,1);
                lcd.print("*");
                i++;
                tone(buzzer, 2000, 100);
              }
            }
            if (i > 5 || keypressed == '#') {
              tempPassword = "";
              i=1;
              tone(buzzer, 2000, 100);
              lcd.clear();
              lcd.setCursor(0,0);
              lcd.print("Set New Password");
              lcd.setCursor(0,1);
              lcd.print(">");
            }
            if ( keypressed == '*') {
              i=1;
              tone(buzzer, 2000, 100);
              password = tempPassword;
              passChangeMode = false;
              passChanged = false;
              screenOffMsg = 0;
            }            
          }
        }
      }
    }
   }
 }
}
void enterPassword() {
  int k=5;
  tempPassword = "";
  activated = true;
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print(" *** ALARM *** ");
  lcd.setCursor(0,1);
  lcd.print("Pass>");
      while(activated) {
      keypressed = myKeypad.getKey();
      if (keypressed != NO_KEY){
        if (keypressed == '0' || keypressed == '1' || keypressed == '2' || keypressed == '3' ||
            keypressed == '4' || keypressed == '5' || keypressed == '6' || keypressed == '7' ||
            keypressed == '8' || keypressed == '9' ) {
          tempPassword += keypressed;
          lcd.setCursor(k,1);
          lcd.print("*");
          k++;
        }
      }
      if (k > 9 || keypressed == '#') {
        tempPassword = "";
        k=5;
        lcd.clear();
        lcd.setCursor(0,0);
        lcd.print(" *** ALARM *** ");
        lcd.setCursor(0,1);
        lcd.print("Pass>");
      }
      if ( keypressed == '*') {
        if ( tempPassword == password ) {
          activated = false;
          alarmActivated = false;
          noTone(buzzer);
          screenOffMsg = 0; 
        }
        else if (tempPassword != password) {
          lcd.setCursor(0,1);
          lcd.print("Wrong! Try Again");
          delay(2000);
          lcd.clear();
          lcd.setCursor(0,0);
          lcd.print(" *** ALARM *** ");
          lcd.setCursor(0,1);
          lcd.print("Pass>");
        }
      }    
    }
}
// Custom function for the Ultrasonic sensor
long getDistance(){
  //int i=10;
  
  //while( i<=10 ) {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance = duration*0.034/2;
  //sumDistance += distance;
  //}
  //int averageDistance= sumDistance/10;
  return distance;
}

Check the project post to know more information and to find detailed tutorial. You can also check other posts by Dejan using this link.

RELATED POSTS

Dual-Channel Quadrature Hall-Effect Bipolar Switch Module for Magnetic Encoder

The A1230 is a dual-channel, bipolar switch with two Hall-effect sensing elements, each providing a separate digital output for speed and direction signal processing capability. The Hall elements are photo lithographically aligned to better than 1 µm. maintaining accurate mechanical location between the two active Hall elements eliminates the major manufacturing hurdle encountered in fine-pitch detection applications. The A1230 is a highly sensitive, temperature stable magnetic sensing device ideal for use in ring magnet based, speed and direction systems located in harsh automotive and industrial environments.

The A1230 monolithic integrated circuit (IC) contains two independent Hall-effect bipolar switches located 1 mm apart. The digital outputs are out of phase so that the outputs are in quadrature when interfaced with the proper ring magnet design. This allows easy processing of speed and direction signals. Extremely low-drift amplifiers guarantee symmetry between the switches to maintain signal quadrature. The Allegro patented, high-frequency chopper-stabilization technique cancels offsets in each channel providing stable operation over the full specified temperature and voltage ranges.

Dual-Channel Quadrature Hall-Effect Bipolar Switch Module for Magnetic Encoder – [Link]