Sep 03 2014
A lot of people when first getting into Arduino projects seem to like robotics. It is fun to create something that you can watch move around. If you are interested in such things, you will be interested to learn about servo motors.
Pictured below is a Parallax Continuous Rotation Servo motor.
Parallax Servo Motor
Click the above image or here to learn more about them and download the Arduino sketch to experiment with them.
Sep 03 2014
There are a number of ways to program AVR microcontroller chips. For my DIY projects, I like to save money by buying components and putting them together to create what I need. I bought some blank ATMEGA 328P micro controllers so that I could make Arduino circuit boards for my projects. Building the Arduino circuit board myself rather than buying the completed Arduino saves money. Granted, it takes more time, but to me it is more satisfying to do it myself.
Since I have blank chips, they need the Arduino Bootloader programmed in. My favorite programmer for that purpose is a Raspberry Pi shown below.
Raspberry Pi
Programmer
It uses a modified version of AVRDude especially for the Raspberry Pi. Instructions on how to get it and use it are here.
Here is how it is wired.
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WIRING THE RPi to the ATMEGA 328 Code ATMEGA RPi RPi GPIO Wire Pin Pin Pin Color ------------------------------------------------------- Reset 1 24 GPIO 8 SPI YELLOW MOSI 17 19 GPIO 10 BROWN MISO 18 21 GPIO 9 ORANGE SCLK 19 23 GPIO 11 BLUE 3.3V 7 17 3.3V GREEN GND 8 25 GND BLACK |
The astute observer will note that besides the 6 wires, I have a 16Mgz crystal on the breadboard. If the chip is blank when it is being programmed this crystal is not needed, however there are times when I reprogram a chip. For those times, the crystal is needed because the fuses are set to use external clocking rather than the internal clock.
Sep 02 2014
A few days ago my son bought me a birthday present. It was a BusPirate from SparkFun. This is what it looks like plugged into a breadboard.
BusPirate and Breadboard
The BusPirate is quite a handy circuit. I have used it to flash a BIOS chip using FLASHROM and also program an AVR ATMEGA 328P with AVRDude.
It can even be used in the Arduino IDE as a programmer simply by adding a few lines:
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buspirate.name=The Bus Pirate buspirate.communication=serial buspirate.protocol=buspirate |
in programmers.txt (found in the hardware directory).
The I/O header [breakout] looks like this:
BusPirate I/O Header
The BusPirate has many uses, check out the possibilities here.
If you’d like to try some of the functions of the BusPirate on an Arduino, you might be interested in the Arduino Sketch called “MiniPirate“. You can find more information here.
Aug 09 2014
A PIR or Passive Infrared module is really fun to play with. This is what they look like:
![Passive Infrared Sensor [front view]](https://microcontrollerelectronics.com/wp-content/uploads/2014/08/pir-sensor_front-300x300.jpg)
![Passive Infrared Sensor [back view]](https://microcontrollerelectronics.com/wp-content/uploads/2014/08/pir-sensor_back-300x300.jpg)
They are basically a motion detector and are called ‘passive’ in the sense that these devices do not generate any energy for detection purposes. They work entirely by detecting the energy given off by other objects in the infrared spectrum wavelengths. More information about infrared can be found here.
Here is how to hook it up:
Get the Fritzing source for the above image here. Once you have it hooked up, head on over to the Arduino Playground and get the sketch to make it work.
I added a buzzer and it alerts me when anything (including the cat) sneaks up on me.
Aug 09 2014
If you’d like to wirelessly attach your Arduino to another device (such as a phone or tablet) via bluetooth, I’d recommend the serial bluetooth module from Elecrow.com.
Here is what they look like:
The module has firmware from BOLUTEK. The PDF document with all of the available BOLUTEK commands is BLK-MD-BC04-B_AT COMMANDS . I also document the AT commands in the sample source code (aduino sketch) below.
There was no sample code that I could find for using these with an Arduino so I wrote my own. The following sketch (load it into any arduino) sets up the module in slave mode so you can connect to it with any blue tooth enabled device. The PIN code is 232323 as you can see from the source.
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# Blue Tooth Module Code # from earl@microcontrollerelectronics.com # #include <SoftwareSerial.h> //Software Serial Port #define RxD 6 #define TxD 7 #define INTERVAL 10000 long previousMillis = 0; char recvChar; SoftwareSerial blueToothSerial(RxD,TxD); void setup() { Serial.begin(9600); while (!Serial); delay(2000); pinMode(RxD, INPUT); pinMode(TxD, OUTPUT); setupBlueToothConnection(); } void BT_cmd(String cmd) { char recvChar; if (cmd != "") { blueToothSerial.print(cmd + "\r\n"); delay(200); } while(blueToothSerial.available()) { recvChar = blueToothSerial.read(); Serial.print(recvChar); } } void loop() { if(millis() - previousMillis > INTERVAL) { previousMillis = millis(); BT_cmd("AT+STATE"); BT_cmd("AT+LSP"); } if(blueToothSerial.available()){ recvChar = blueToothSerial.read(); Serial.print(recvChar); } if(Serial.available()){ recvChar = Serial.read(); blueToothSerial.print(recvChar); } } void setupBlueToothConnection() { /* AT Check if the command terminal work normally AT+RESET Software reboot AT+VERSION Get firmware, bluetooth, HCI and LMP version AT+HELP List all the commands AT+NAME Get/Set local device name AT+PIN Get/Set pin code for pairing AT+BAUD Get/Set baud rate AT+CLEAR Remove the remembered remote address AT+LADDR Get local bluetooth address AT+RNAME Get remote device name AT+DEFAULT Restore factory default AT+CMODE Get/Set connection mode AT+BIND Get/Set bind bluetooth address AT+COD Get/Set local class of device AT+IAC Get/Set inquiry access code AT+ROLE Get/Set master or slave mode AT+STATE Get current state AT+SENM Get/Set security and encryption mode AT+IPSCAN Get/Set page and inquiry scan parameters AT+SNIFF Get/Set sniff power table parameters AT+LOWPOWER Start/Stop low power mode AT+UARTMODE Get/Set uart stop bits and parity AT+ENABLEIND Enable/Disable Indication print AT+LSP List Paired Device List AT+RESETPDL Reset Paired Device List AT+REMOVEPDL Remove one entry from Paired Device List AT+SUPERVISION Get/Set supervision timeout AT+AUTOINQ Start/Stop auto inquiry AT+INQ Start inquiry AT+INQC Cancel ongoing inquiry (M)AT+AUTOCONN Start/Stop auto connection (M)AT+INQM Get/Set inquiry parameters (M)AT+CONNECT Connect to a remote device by BD address */ blueToothSerial.begin(9600); delay(1000); BT_cmd("AT+ENABLEIND1"); //Enable Indications BT_cmd("AT+ROLE0"); //set the bluetooth to work in slave mode BT_cmd("AT+NAMEArduinoBTSlave"); //set the bluetooth name BT_cmd("AT+PIN232323"); //set PIN BT_cmd("AT+AUTOINQ1"); //Automatic Search Serial.println("\r\nThe slave bluetooth is inquirable!"); } |
Aug 07 2014
I picked up a couple of these modules:
from Elecrow.com so I could attach (communicate with and control) several of my Arduinos through a LAN connection.
The main chip is the ENC28J60 from microchip.com. These modules are better than an Ethernet Shield in that you can easily attach these to any Arduino and they are less expensive than a shield.
I have found (and you will too if you GOOGLE this module) that even though they say 3.3V input, they don’t work well at that voltage. They run perfectly when supplied by the Arduino 5V pin.
To run your Arduino sketch pick up a copy of the needed ENC28J60 library from Elecrow here.
Need more information or sample code? I found the best information about using this module is here: tweaking4all.com
Aug 07 2014
[warning]Careful! Don’t let the smoke out![/warning]
Hopefully you’ve never ruined any electronics device due to applying too much power. Some people have (cough, cough .. the voice of experience) and when this happens the device or component goes up in smoke. In popular jargon it is said to have “lost its smoke“.
When working with various components, always check their voltage ratings and make sure the input voltage does not exceed those limits. Also, even with correct voltages, if certain components are wired wrong (like polarized capacitors) they can still be damaged.
So it pays to always double check things before you hit that power on button!
Aug 06 2014
OBD-II (an abbreviation for On-Board Diagnostics, Second Generation) is a set of standards for implementing a computer based system to control emissions from vehicles ( and a lot more ! ). If you are not familiar with OBD-II you can read more about it here.
I just recently acquired an OBD-II UART board and cable
from SparkFun.com, so I can diagnose any car problems. One end of the cable connects to the OBD-II connector on your car, the other end connects to the board. The board can then connect to any serial port via a 6 pin header that needs to be soldered on.
The 6 pin header connects nicely to an FTDI board
that Sparkfun.com also sells. The tutorial about this product shows how to attach an arduino and LCD monitor to capture data from your cars’ computer.
The board did not come with any OBD-II diagnostic / analysis software but there are a number of FREE and commercial offerings to choose from.
I like to write my own software and so I came up with this Python script to inquire for and analyze the OBD information. It is too big to post here so just click on the image to download it.
If you’d like to test the Python code but do not have the OBD-II UART, you can substitute any Arduino you might have lying around. I wrote a simple sketch to emulate the OBD-II information coming from a ‘sample’ car. Just attach the arduino to your computer via any USB cable, load the sketch and run the Python script.
I tested it with my Aduino Nano.
Here is the sketch:
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# Arduino Sketch to emulate an OBD-II connection # from earl@microcontrollerelectronics.com # String inputString = ""; boolean stringComplete = false; void setup() { Serial.begin(9600); inputString.reserve(200); Serial.println(">"); } void loop() { if (stringComplete) { int len = inputString.length(); String ans = "4" + inputString.substring(1,2) + " "; if (len > 4) ans = ans + inputString.substring(3,5) + ":"; else if (len > 3) ans = ans + inputString.substring(2,4) + ":"; else if (len > 2) ans = ans + inputString.substring(3,4) + ":"; if (inputString.substring(0,3) == "ATZ") Serial.println("ELM327 v1.4"); else if (inputString.substring(0,2) == "AT") Serial.println("OK"); else if (inputString.substring(0,5) == "01 00") Serial.println("41 00:FF FF FC FF"); else if (inputString.substring(0,5) == "01 01") Serial.println("41 01:84 07 61 00"); else if (inputString.substring(0,5) == "01 20") Serial.println("41 20:FF FF FC FF"); else if (inputString.substring(0,5) == "01 40") Serial.println("41 40:FF FF FC FF"); else if (inputString.substring(0,5) == "01 60") Serial.println("41 60:FF FF FC FF"); else if (inputString.substring(0,5) == "01 80") Serial.println("41 80:FF FF FC FF"); else if (inputString.substring(0,5) == "01 A0") Serial.println("41 A0:FF FF FC FF"); else if (inputString.substring(0,5) == "01 C0") Serial.println("41 C0:FF FF FC FF"); else if (inputString.substring(0,2) == "01") Serial.println(ans + "00 00 00 00"); else if (inputString.substring(0,2) == "03") Serial.println("43 03 00 03 01 03\r\n43 13 01 04"); else if (inputString.substring(0,5) == "09 02") Serial.println("49 02:1Z3768470804"); else Serial.println(ans + "NO DATA"); Serial.println(">"); inputString = ""; stringComplete = false; } } void serialEvent() { while (Serial.available()) { char inChar = (char)Serial.read(); if (inChar == '\n') continue; if (inChar == '\r') { stringComplete = true; if (inputString == "") inputString = "NULL"; inputString.toUpperCase(); continue; } inputString += inChar; } } |
Aug 04 2014
Many years ago (I am old ;-)) I was asked which microcontrollers are best, ones from PIC (microchip.com) or ones from Atmel (atmel.com).
At the time I was asked, there was a lot of discussion about chip architecture, instruction sets and which chip was best.
I thought at the time and still feel this way, it depends on too many factors to say which is best.
Certainly with the popularity of the Arduino the Atmega series of chips from Atmel got a boost in popularity.
For most of my projects, I find myself using an Atmega 328p mostly because I can buy it locally in my favorite electronics store cheaply and It is easily programmed with the Arduino IDE.
Aug 04 2014
If you need a way to design a circuit or show a nice graphic of it for someone else to follow, you might consider Fritzing from fritzing.org.
A quote from their website:
Fritzing is an open-source hardware initiative that makes electronics accessible as a creative material for anyone. Fritzing.org offers a software tool, a community website and services in the spirit of Processing and Arduino, fostering a creative ecosystem that allows users to document their prototypes, share them with others, teach electronics in a classroom,and layout and manufacture professional pcbs.
Fritzing software is vector based so you can, drag and drop circuit components, easily re-size and attach wires.
It allows you to make COOL looking graphics like this:
The Fritzing software comes with an extensive libary of components, however there are others who have created libraries of parts too. One of my favorite Internet hangouts is Adafruit.com. They have created a Fritzing library of parts which you can find on Github here.
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