Kite photographing the BP oil spill is a group of people who are documenting BP's oil spill with cameras held aloft by kites and balloons. Sometimes they even get a ride on a plane. All of the images produced with this method will be going into the public domain. It's cool stuff and the images are far better than anything else out there. To keep the project going and cover the costs, they've set up a page on kickstarter to ask for donations. They've already passed their initial goal of $5,000, but it's a good cause and I hope they get plenty more than that. I pledged some money and wish them all the best.

Topic by fungus amungus   |  last reply

Is this the right way to check for object detection with a IR sensor? Answered

Sensor: Link Hi, i'm using the sensor to test for detection. (eg when my hand is on top of the sensor, it will send a signal to a buzzer). Not sure if this is the right way for detection. Any improvements/tips are welcome. int sensorPin = 1; int lastDist = 1000; //set to a high amount to prevent false detection when powering up int currentDist = 0; int thresh = 25; void setup() {   // initialise serial communications at 9600 bps:   Serial.begin(9600); } void loop() {   currentDist = analogRead(sensorPin);   Serial.println(currentDist);   // compare currentDist with lastDist & thresh to determine if any objects is detected   if (currentDist > lastDist + thresh)   {     Serial.println("detection alert!");   } else {     Serial.println("no detection");   }   lastDist = currentDist; }

Question by Zaineen   |  last reply

Arduino NANO error uploading sketch. After attempted loading of NANO clone (ELEGOO) the IDE hangs -

The Com port was selected, old bootloader selected. Various error messages (will collect and add to post here). However the very strange thing is that the NANO is sending to the Serial Monitor at 115200 BPS the message"Loaded next response 1" continuously!OS is Win 10 64 bit - current version with all updates.USB Driver is USB Serial CH-340 version 3.5.2019.1 dated 1/30/2019.This appears to be a new issue that appeared after I attempted to run two instances of the IDE with two NANOs attached. One on COM4 and the other on COM11.I have deleted and reinstalled the driver - same issue.Going to try on another PC.Anyone have any ideas?

Question by Rozzer   |  last reply

Sound Locator Circuit?

Hey all, Here's an idea maybe one of you solder-jockeys can help me out with: Ever have a sound that you'd like to find the source of, but your ears can't tell you where it's coming from?  I'd like to build a circuit to do that. I was thinking of something like three electret microphones with op-amps between them in differential mode.  That would give three signals that would be, presumably, the ratio of sound coming from each mic.  (And, therefore, an indication of direction.) Of course, I'd also like to get an adjustable bandpass filter in there somewhere to isolate just the sound I'm looking for.  That's the part that complicates all designs I've thought of. And then, if I could somehow figure out distance too, that would be the ULTIMATE! Here's one possible use case: A car makes a funny squeal noise a highway speeds. The mechanic takes out this device and magnets it inside the hood.  He runs a control wire back to the cabin. Once the car is in motion and making the desire noise, he adjusts the BP filter using potentiometer(s) and a pair of headphones. The device tells him where (relative to itsself) the sound is coming from. Your bill is less because the problem was diagnosed quickly without a lot of guesswork. Thoughts?

Topic by PS118   |  last reply


Hello guruz, recently i bought n bluetooth UART module (;_id=354) RKI 1545 I tried interfacing it with 8051 using the 10,11 pin UART pins, using SCON register(mode1) baud rate 9600. But there is no reception or transmission. However the bt module is working fine. Passed the loop feedback test(joined theRx to Tx pin of module established echo received on Putty on WIN7 and blueterm android app )   CODE: #include void ini()     // Initialize Timer 1 for serial communication { TMOD=0x20;  //Timer1, mode 2, baud rate 9600 bps TH1=0XFD; SCON=0x51; TR1=1; } void recieve()  //Function to receive serial data { unsigned char value; while(RI==0); value=SBUF; P1=value; RI=0; } void transmit()  // Funtion to transmit serial data { P2=0xF4; SBUF=P2; while(TI==0); TI=0; SBUF=P1; while(TI==0); TI=0; } void main() { while(1) {   ini();   recieve();   transmit(); } }

Topic by skumar112   |  last reply

arduino code nedded

HI, MY  NAME IS THIAGO IKEDA AND HERE IS MY FIRST "ASK" my english is VERY bad. well sorry anyway FIRST  i made this arduino tank (named ardutank) with ladyada motor shield and i used library and worked then i like WOW I SUPER GENIUS so i buy an HC-SR04(ULTRASONIC SENSOR) to put with ARDUTANK, and i used the library too but when i upload the code the ARDUTANK START make some wild noises. i dont know what to do to ARDUTANK work with the sensor obs: in first mode (with out ultrasonic sensor) one motor spins more fast than other, WHY? the bouth motors are the same motor. but when i put to HIM to RUN HE make lil curve. here is code WITH SENSOR PLEASE IGNORE THE RELE AND BUZER NEXT TO SENSOR // Adafruit Motor shield library // copyright Adafruit Industries LLC, 2009 // this code is public domain, enjoy! #include #include #define TRIGGER_PIN  12 #define ECHO_PIN     13 int distance; Ultrasonic ultrasonic(TRIGGER_PIN, ECHO_PIN); AF_DCMotor motor1(1); AF_DCMotor motor2(2); void setup() {   Serial.begin(9600);           // set up Serial library at 9600 bps   Serial.println("Motor test!");   // turn on motor   delay(10);   motor1.setSpeed(20);   motor2.setSpeed(20);;; } void loop() {   uint8_t i;   float cmMsec, inMsec;   long microsec = ultrasonic.timing();   cmMsec = ultrasonic.convert(microsec, Ultrasonic::CM);   inMsec = ultrasonic.convert(microsec, Ultrasonic::IN);   Serial.print("tick");;;   if(distance<10) {;; } else {;; } }

Question by crazy_thiago   |  last reply

: Arduino + Adafruit wave sheild + IR + Keypad sound board

Hi , was wondering if you could point me in the right direction I'm very new to Arduino I built last year a simple board with adafruit wave shield and added a simple 12 digit key pad to play 12 sounds + power up I have got the codes for the KEYES IR receiver so know the IR is correctly connected and library loaded im trying to integrate the IR code so can change the sounds by IR remote ideally with option of the buttons (if have to loose the buttons and just use remote that's fine) have copied the code below for how it works now just buttons   I found some code for Cylon Pumpkin that works great with just the remote but would also like to integrate the 12 digit keypad Thank you in advance for any help or pointers you can suggest Richard CODE FOR 12 DIGIT BUTTON PRESS /* ADAVOICE is an Arduino-based voice pitch changer plus WAV playback. Fun for Halloween costumes, comic convention getups and other shenanigans! Hardware requirements: - Arduino Uno, Duemilanove or Diecimila (not Mega or Leonardo compatible). - Adafruit Wave Shield - Speaker attached to Wave Shield output - Battery for portable use If using the voice pitch changer, you will also need: - Adafruit Microphone Breakout - 10K potentiometer for setting pitch (or hardcode in sketch) If using the WAV playback, you will also need: - SD card - Keypad, buttons or other sensor(s) for triggering sounds Software requirements: - WaveHC library for Arduino - Demo WAV files on FAT-formatted SD card This example sketch uses a 3x4 keypad for triggering sounds...but with some changes could be adapted to use several discrete buttons, Hall effect sensors, force-sensing resistors (FSRs), I2C keypads, etc. (or if you just want the voice effect, no buttons at all). Connections: - 3.3V to mic amp+, 1 leg of potentiometer and Arduino AREF pin - GND to mic amp-, opposite leg of potentiometer - Analog pin 0 to mic amp output - Analog pin 1 to center tap of potentiometer - Wave Shield output to speaker or amplifier - Matrix is wired to pins A2, A3, A4, A5 (rows) and 6, 7, 8 (columns) - Wave shield is assumed wired as in product tutorial Potentiometer sets playback pitch. Pitch adjustment does NOT work in realtime -- audio sampling requires 100% of the ADC. Pitch setting is read at startup (or reset) and after a WAV finishes playing. POINT SPEAKER AWAY FROM MIC to avoid feedback. Written by Adafruit industries, with portions adapted from the 'PiSpeakHC' sketch included with WaveHC library. */ #include #include SdReader card; // This object holds the information for the card FatVolume vol; // This holds the information for the partition on the card FatReader root; // This holds the information for the volumes root directory FatReader file; // This object represent the WAV file for a pi digit or period WaveHC wave; // This is the only wave (audio) object, -- we only play one at a time #define error(msg) error_P(PSTR(msg)) // Macro allows error messages in flash memory #define ADC_CHANNEL 0 // Microphone on Analog pin 0 // Wave shield DAC: digital pins 2, 3, 4, 5 #define DAC_CS_PORT PORTD #define DAC_CS PORTD2 #define DAC_CLK_PORT PORTD #define DAC_CLK PORTD3 #define DAC_DI_PORT PORTD #define DAC_DI PORTD4 #define DAC_LATCH_PORT PORTD #define DAC_LATCH PORTD5 uint16_t in = 0, out = 0, xf = 0, nSamples; // Audio sample counters uint8_t adc_save; // Default ADC mode // WaveHC didn't declare it's working buffers private or static, // so we can be sneaky and borrow the same RAM for audio sampling! extern uint8_t buffer1[PLAYBUFFLEN], // Audio sample LSB buffer2[PLAYBUFFLEN]; // Audio sample MSB #define XFADE 16 // Number of samples for cross-fade #define MAX_SAMPLES (PLAYBUFFLEN - XFADE) // Remaining available audio samples // Keypad information: uint8_t rows[] = { A2, A3, A4, A5 }, // Keypad rows connect to these pins cols[] = { 6, 7, 8, 9 }, // Keypad columns connect to these pins r = 0, // Current row being examined prev = 255, // Previous key reading (or 255 if none) count = 0; // Counter for button debouncing #define DEBOUNCE 10 // Number of iterations before button 'takes' // Keypad/WAV information. Number of elements here should match the // number of keypad rows times the number of columns, plus one: const char *sound[] = { "Crashing" , "Damaged", "InFlight" , "PowerUp" , // Row 1 = Darth Vader sounds "Brkdown3" , "Brkdown2" , "Brkdown" , "PowerUp" , // Row 2 = Godzilla sounds "Landing", "drain" , "Shutdown" , "PowerUp" , // Row 3 = Dug the dog sounds "Silent", "TakeOff", "Vortex" , "PowerUp" , // Row 4 = Cartoon/SFX sound "PowerUp" }; // Extra item = boot sound //////////////////////////////////// SETUP void setup() { uint8_t i; Serial.begin(9600); // The WaveHC library normally initializes the DAC pins...but only after // an SD card is detected and a valid file is passed. Need to init the // pins manually here so that voice FX works even without a card. pinMode(2, OUTPUT); // Chip select pinMode(3, OUTPUT); // Serial clock pinMode(4, OUTPUT); // Serial data pinMode(5, OUTPUT); // Latch digitalWrite(2, HIGH); // Set chip select high // Init SD library, show root directory. Note that errors are displayed // but NOT regarded as fatal -- the program will continue with voice FX! if(!card.init()) SerialPrint_P("Card init. failed!"); else if(!vol.init(card)) SerialPrint_P("No partition!"); else if(!root.openRoot(vol)) SerialPrint_P("Couldn't open dir"); else { PgmPrintln("Files found:");; // Play startup sound (last file in array). playfile(sizeof(sound) / sizeof(sound[0]) - 1); } // Optional, but may make sampling and playback a little smoother: // Disable Timer0 interrupt. This means delay(), millis() etc. won't // work. Comment this out if you really, really need those functions. TIMSK0 = 0; // Set up Analog-to-Digital converter: analogReference(EXTERNAL); // 3.3V to AREF adc_save = ADCSRA; // Save ADC setting for restore later // Set keypad rows to outputs, set to HIGH logic level: for(i=0; i pinMode(rows[i], OUTPUT); digitalWrite(rows[i], HIGH); } // Set keypad columns to inputs, enable pull-up resistors: for(i=0; i pinMode(cols[i], INPUT); digitalWrite(cols[i], HIGH); } while(wave.isplaying); // Wait for startup sound to finish... startPitchShift(); // and start the pitch-shift mode by default. } //////////////////////////////////// LOOP // As written here, the loop function scans a keypad to triggers sounds // (stopping and restarting the voice effect as needed). If all you need // is a couple of buttons, it may be easier to tear this out and start // over with some simple digitalRead() calls. void loop() { uint8_t c, button; // Set current row to LOW logic state... digitalWrite(rows[r], LOW); // ...then examine column buttons for a match... for(c=0; c if(digitalRead(cols[c]) == LOW) { // First match. button = r * sizeof(cols) + c; // Get button index. if(button == prev) { // Same button as before? if(++count >= DEBOUNCE) { // Yes. Held beyond debounce threshold? if(wave.isplaying) wave.stop(); // Stop current WAV (if any) else stopPitchShift(); // or stop voice effect playfile(button); // and play new sound. while(digitalRead(cols[c]) == LOW); // Wait for button release. prev = 255; // Reset debounce values. count = 0; } } else { // Not same button as prior pass. prev = button; // Record new button and count = 0; // restart debounce counter. } } } // Restore current row to HIGH logic state and advance row counter... digitalWrite(rows[r], HIGH); if(++r >= sizeof(rows)) { // If last row scanned... r = 0; // Reset row counter // If no new sounds have been triggered at this point, and if the // pitch-shifter is not running, re-start it... if(!wave.isplaying && !(TIMSK2 & _BV(TOIE2))) startPitchShift(); } } //////////////////////////////////// HELPERS // Open and start playing a WAV file void playfile(int idx) { char filename[13]; (void)sprintf(filename,"%s.wav", sound[idx]); Serial.print("File: "); Serial.println(filename); if(!, filename)) { PgmPrint("Couldn't open file "); Serial.print(filename); return; } if(!wave.create(file)) { PgmPrintln("Not a valid WAV"); return; }; } //////////////////////////////////// PITCH-SHIFT CODE void startPitchShift() { // Read analog pitch setting before starting audio sampling: int pitch = analogRead(1); Serial.print("Pitch: "); Serial.println(pitch); // Right now the sketch just uses a fixed sound buffer length of // 128 samples. It may be the case that the buffer length should // vary with pitch for better results...further experimentation // is required here. nSamples = 128; //nSamples = F_CPU / 3200 / OCR2A; // ??? //if(nSamples > MAX_SAMPLES) nSamples = MAX_SAMPLES; //else if(nSamples < (XFADE * 2)) nSamples = XFADE * 2; memset(buffer1, 0, nSamples + XFADE); // Clear sample buffers memset(buffer2, 2, nSamples + XFADE); // (set all samples to 512) // WaveHC library already defines a Timer1 interrupt handler. Since we // want to use the stock library and not require a special fork, Timer2 // is used for a sample-playing interrupt here. As it's only an 8-bit // timer, a sizeable prescaler is used (32:1) to generate intervals // spanning the desired range (~4.8 KHz to ~19 KHz, or +/- 1 octave // from the sampling frequency). This does limit the available number // of speed 'steps' in between (about 79 total), but seems enough. TCCR2A = _BV(WGM21) | _BV(WGM20); // Mode 7 (fast PWM), OC2 disconnected TCCR2B = _BV(WGM22) | _BV(CS21) | _BV(CS20); // 32:1 prescale OCR2A = map(pitch, 0, 1023, F_CPU / 32 / (9615 / 2), // Lowest pitch = -1 octave F_CPU / 32 / (9615 * 2)); // Highest pitch = +1 octave // Start up ADC in free-run mode for audio sampling: DIDR0 |= _BV(ADC0D); // Disable digital input buffer on ADC0 ADMUX = ADC_CHANNEL; // Channel sel, right-adj, AREF to 3.3V regulator ADCSRB = 0; // Free-run mode ADCSRA = _BV(ADEN) | // Enable ADC _BV(ADSC) | // Start conversions _BV(ADATE) | // Auto-trigger enable _BV(ADIE) | // Interrupt enable _BV(ADPS2) | // 128:1 prescale... _BV(ADPS1) | // ...yields 125 KHz ADC clock... _BV(ADPS0); // ...13 cycles/conversion = ~9615 Hz TIMSK2 |= _BV(TOIE2); // Enable Timer2 overflow interrupt sei(); // Enable interrupts } void stopPitchShift() { ADCSRA = adc_save; // Disable ADC interrupt and allow normal use TIMSK2 = 0; // Disable Timer2 Interrupt } ISR(ADC_vect, ISR_BLOCK) { // ADC conversion complete // Save old sample from 'in' position to xfade buffer: buffer1[nSamples + xf] = buffer1[in]; buffer2[nSamples + xf] = buffer2[in]; if(++xf >= XFADE) xf = 0; // Store new value in sample buffers: buffer1[in] = ADCL; // MUST read ADCL first! buffer2[in] = ADCH; if(++in >= nSamples) in = 0; } ISR(TIMER2_OVF_vect) { // Playback interrupt uint16_t s; uint8_t w, inv, hi, lo, bit; int o2, i2, pos; // Cross fade around circular buffer 'seam'. if((o2 = (int)out) == (i2 = (int)in)) { // Sample positions coincide. Use cross-fade buffer data directly. pos = nSamples + xf; hi = (buffer2[pos] << 2) | (buffer1[pos] >> 6); // Expand 10-bit data lo = (buffer1[pos] << 2) | buffer2[pos]; // to 12 bits } if((o2 < i2) && (o2 > (i2 - XFADE))) { // Output sample is close to end of input samples. Cross-fade to // avoid click. The shift operations here assume that XFADE is 16; // will need adjustment if that changes. w = in - out; // Weight of sample (1-n) inv = XFADE - w; // Weight of xfade pos = nSamples + ((inv + xf) % XFADE); s = ((buffer2[out] << 8) | buffer1[out]) * w + ((buffer2[pos] << 8) | buffer1[pos]) * inv; hi = s >> 10; // Shift 14 bit result lo = s >> 2; // down to 12 bits } else if (o2 > (i2 + nSamples - XFADE)) { // More cross-fade condition w = in + nSamples - out; inv = XFADE - w; pos = nSamples + ((inv + xf) % XFADE); s = ((buffer2[out] << 8) | buffer1[out]) * w + ((buffer2[pos] << 8) | buffer1[pos]) * inv; hi = s >> 10; // Shift 14 bit result lo = s >> 2; // down to 12 bits } else { // Input and output counters don't coincide -- just use sample directly. hi = (buffer2[out] << 2) | (buffer1[out] >> 6); // Expand 10-bit data lo = (buffer1[out] << 2) | buffer2[out]; // to 12 bits } // Might be possible to tweak 'hi' and 'lo' at this point to achieve // different voice modulations -- robot effect, etc.? DAC_CS_PORT &= ~_BV(DAC_CS); // Select DAC // Clock out 4 bits DAC config (not in loop because it's constant) DAC_DI_PORT &= ~_BV(DAC_DI); // 0 = Select DAC A, unbuffered DAC_CLK_PORT |= _BV(DAC_CLK); DAC_CLK_PORT &= ~_BV(DAC_CLK); DAC_CLK_PORT |= _BV(DAC_CLK); DAC_CLK_PORT &= ~_BV(DAC_CLK); DAC_DI_PORT |= _BV(DAC_DI); // 1X gain, enable = 1 DAC_CLK_PORT |= _BV(DAC_CLK); DAC_CLK_PORT &= ~_BV(DAC_CLK); DAC_CLK_PORT |= _BV(DAC_CLK); DAC_CLK_PORT &= ~_BV(DAC_CLK); for(bit=0x08; bit; bit>>=1) { // Clock out first 4 bits of data if(hi & bit) DAC_DI_PORT |= _BV(DAC_DI); else DAC_DI_PORT &= ~_BV(DAC_DI); DAC_CLK_PORT |= _BV(DAC_CLK); DAC_CLK_PORT &= ~_BV(DAC_CLK); } for(bit=0x80; bit; bit>>=1) { // Clock out last 8 bits of data if(lo & bit) DAC_DI_PORT |= _BV(DAC_DI); else DAC_DI_PORT &= ~_BV(DAC_DI); DAC_CLK_PORT |= _BV(DAC_CLK); DAC_CLK_PORT &= ~_BV(DAC_CLK); } DAC_CS_PORT |= _BV(DAC_CS); // Unselect DAC if(++out >= nSamples) out = 0; } CODE I FOUND FOR IR  ClyonPumpkin That I want to integrate in above   /* * Text-to-speech example to speak the first n digits of pi. * The number is stored in flash, each digit is spoken one at a time. */ #include #include #include SdReader card;    // This object holds the information for the card FatVolume vol;    // This holds the information for the partition on the card FatReader root;   // This holds the information for the volumes root directory FatReader file;   // This object represent the WAV file for a pi digit or period WaveHC wave;      // This is the only wave (audio) object, since we will only play one at a time char eyesound[13]="eye2.wav"; int mute = 0; /* * Define macro to put error messages in flash memory */ #define error(msg) error_P(PSTR(msg)) // IR Remote code int RECV_PIN = 9;  // pin 11 used by SD card interface so select pin 9 for IR IRrecv irrecv(RECV_PIN); decode_results results; long lasttime=0, lastcode=0, timediff=0; //////////////////////////////////// SETUP void setup() {   // set up Serial library at 9600 bps   Serial.begin(9600);               if (!card.init()) {     error("Card init. failed!");   }   if (!vol.init(card)) {     error("No partition!");   }   if (!root.openRoot(vol)) {     error("Couldn't open dir");   }   irrecv.enableIRIn(); // Start the IR receiver } /////////////////////////////////// LOOP void loop() {   if(mute == 0) playcomplete(eyesound);   // check for keypress happened   if (irrecv.decode(&results;)) {      Serial.println(results.value, HEX);      switch (results.value) {        case 0x83228B74:    // 1          playcomplete("command.wav");          break;        case 0x83228F70:    // 2          playcomplete("entertan.wav");          break;        case 0x8322906F:    // 3          playcomplete("extermin.wav");          break;        case 0x83228A75:    // 4          playcomplete("leader.wav");          break;        case 0x8322847B:    // 5          playcomplete("survivor.wav");          break;         case 0x83227887:    // 6          playcomplete("atention.wav");          break;        case 0x8322629D:    // vol up          mute = 0;         // mute off          break;         case 0x83226E91:    // mute          { Serial.println("mute detected");            timediff=millis()-lasttime;            Serial.println(timediff);            if(lastcode!=results.value || (lastcode==results.value && (timediff>1600)) ) {               if( mute == 0 ) { // is mute off?                  Serial.println("toggle off to on");                  mute = 1;      // turn on                  // delay(1000);    // wait a bit for debounce                  break;                 }               if( mute == 1 ) { // is mute on?                  mute = 0;      // turn off                  Serial.println("toggle on to off");                  break;                 }              } // end if             break;           } // end case        } // end switch      lastcode = results.value;      lasttime = millis();      irrecv.resume();   // Receive the next value   } } /////////////////////////////////// HELPERS /* * print error message and halt */ void error_P(const char *str) {   PgmPrint("Error: ");   SerialPrint_P(str);   sdErrorCheck();   while(1); } /* * print error message and halt if SD I/O error */ void sdErrorCheck(void) {   if (!card.errorCode()) return;   PgmPrint("\r\nSD I/O error: ");   Serial.print(card.errorCode(), HEX);   PgmPrint(", ");   Serial.println(card.errorData(), HEX);   while(1); } /* * Play a file and wait for it to complete */ void playcomplete(char *name) {   playfile(name);   while (wave.isplaying);     // see if an error occurred while playing   sdErrorCheck(); } /* * Open and start playing a WAV file */ void playfile(char *name) {   if (wave.isplaying) {// already playing something, so stop it!     wave.stop(); // stop it   }   if (!, name)) {     PgmPrintln("Couldn't open file ");     Serial.print(name);     return;   }   if (!wave.create(file)) {     PgmPrintln("Not a valid WAV");     return;   }   // ok time to play!; }

Topic by SithLordIII 

500W electric scooter control and instrumentation with Arduino mega

1. Introduction DC 500W motor control with an Arduino mega to limit starting current and to vary the speed of the scooter. The battery is in 24V, 10A.h. The following table summarizes their characteristics: 2. Bibliography: Link download : sketch_escooter_feed_back_reel_V1.ino escooter_ampli_SIMULINK.mdl escooter feed back ISIS.DSN youtube  :  "study trotinette electric e-scooter 100W et 350W, wiring"  youtube;=75&list;=PLfZunVn_gcq7EOurXuWU2sRFmh6CbiUiL Article: «Study of electric scooters 100W and 500W (Arduino), Revue 3EI 2017» Pdf? Book «I realize my electric vehicle» at DUNOD 3. Open loop program To test the programming, we simulate the program in ISIS, as can be seen in the following figure. In addition, we have an LCD display to display data (duty cycle corresponding to the PWM at 32Khz, motor current, motor voltage, action on the pushbuttons, 4 push buttons are used. BP1 to manually increment the duty cycle, BP2 decrement it. BP3 set the duty cycle to 0, corresponding to the brake contact. The speed of the motor is practically proportional to the duty cycle We made our own current amplifier called a step-down chopper but it is possible to buy a shield There are many cards for Arduino to control DC motors especially of low powers and also of great powers as can be observed on the following links. But all these chopper shields measure the current internally but there is no current limitation. In order to have a current limitation, an analog current loop is required using specialized AOP or IC or a fast digital current loop. But what should be the value of the limitation current? The choice of the current value is normally for the 1-hour operation service in order to be able to carry out relatively long climbs without reaching the critical temperature of the engine. In our case, the limitation current must be Limiting motor = Power / Upper battery = 500W / 24V = 20A In addition, the power transistor of the chopper can only support 50A in our case. But in open loop, it has no current regulation, so as not to exceed the maximum current, a ramp of the duty cycle will be used. A 0.1 second interruption routine will be used to measure the voltage of the current (sample measurement, sample). This sampling time is arbitrary but does not allow to be faster than the rise time of the current because the electric time constant of the motor is L / R = 1.5 ms. Open loop operation with a 25.5s (8bit) ramp and 0.1s interrupt routine provides a good understanding of the operation of a DC motor drive. The display will only be done every 0.2s to have a stability of the digits on the screen. In addition, a digital filtering will be done on the current and the voltage on 4 values therefore on 0.4s. [b] Algo open loop [/b] Interrupt Routine All 0.1S Read voltage and current Loop loop (push button scan) If BP1 = 1 then increment PWM If BP2 = 1 then decrement PWM If BP3 = 1 then PWM = 0 Displaying variables every 0.2s Code: [Select] // include the library code: #include #include #include #define SERIAL_PORT_LOG_ENABLE 1 #define Led     13       // 13 for the yellow led on the map #define BP1     30       // 30 BP1 #define BP2     31       // 31 BP2           #define BP3     32       // 32 BP3 #define LEDV    33       // 33 led #define LEDJ    34       // 34 led #define LEDR    35       // 35 led #define relay   36       // 36 relay #define PWM10    10      //11   timer2    LiquidCrystal lcd(27, 28, 25, 24, 23, 22); // RS=12, Enable=11, D4=5, D5=4, D6= 3, D7=2, BPpoussoir=26 // Configuring variables unsigned   int UmoteurF = 0;  // variable to store the value coming from the sensor unsigned   int Umoteur = 0; unsigned   int Umoteur2 = 0; unsigned   int Umoteur3 = 0; unsigned   int Umoteur4 = 0; unsigned   int ImoteurF = 0;  unsigned   int Imoteur = 0; unsigned   int Imoteur2 = 0; unsigned   int Imoteur3 = 0; unsigned   int Imoteur4 = 0;            byte Rcy=0 ;    // 8bit duty cycle unsigned    int temps; // the setup function runs once when you press reset or power the board void setup() {   pinMode(Led, OUTPUT);   // Arduino card   pinMode(LEDV, OUTPUT);   pinMode(LEDR, OUTPUT);   pinMode(LEDJ, OUTPUT);   pinMode (PWM10,OUTPUT);     // Pin (10) output timer2   //  digitalWrite(LEDV,LOW);   Timer1.initialize(100000);         // initialize timer1, and set a 0,1 second period =>  100 000   Timer1.attachInterrupt(callback);  // attaches callback() as a timer overflow interrupt   lcd.begin(20, 4);    Serial1.begin(9600);   TCCR2B = (TCCR2B & 0b11111000) | 0x01;         //pin 10  32khz                                                   //   //   analogWriteResolution(bits) lcd.setCursor(0,1); lcd.print("Rcy"); lcd.setCursor(10,1); lcd.print("Um"); lcd.setCursor(5,1); lcd.print("Im"); lcd.setCursor(10,1); lcd.print("Um"); lcd.setCursor(20,1); // 4 lines display * 20 characters lcd.print("BP1+"); lcd.setCursor(25,1); lcd.print("BP2-"); lcd.setCursor(29,1); lcd.print("BP3=0"); } // Interruptions  tous les 0.1s void callback()  { temps++; //toogle state ledv for check   if ( digitalRead(LEDV)== 1 ) {digitalWrite(LEDV,LOW);}     else {digitalWrite(LEDV,HIGH);}     analogWrite(PWM10,Rcy);   // frequency Umoteur=analogRead(A0); Imoteur=analogRead(A1); Imoteur2=Imoteur; Imoteur3=Imoteur2; Imoteur4=Imoteur3; ImoteurF=(Imoteur4+Imoteur3+Imoteur2+Imoteur)/4 ; Umoteur2=Umoteur; Umoteur3=Umoteur2; Umoteur4=Umoteur3; UmoteurF=(Umoteur4+Umoteur3+Umoteur2+Umoteur)/4 ;   }// End routine // Loop corresponding to main function void loop() {    // BP + LED   if ((digitalRead(BP1))==1) {     lcd.setCursor(20,0);      // Column line     lcd.print("BP1");     digitalWrite(LEDR, LOW);        digitalWrite(LEDJ, LOW);     Rcy++;                        // PWM incrementation     if ( Rcy>254)  {Rcy=254;}     delay(100);               //8bits * 100ms = 25S increment 25ssecond slope     }        if ((digitalRead(BP2))==1) {     lcd.setCursor(20,0);     lcd.print("BP2");             Rcy--;      if ( Rcy<2)  {Rcy=2;}  // PWM almost at 0, engine stop         delay(100);      digitalWrite(LEDR, HIGH);     digitalWrite(LEDJ, HIGH);     }   if ((digitalRead(BP3))==1) {     lcd.setCursor(20,0);     lcd.print("BP3");      Rcy=2;               // PWM almost at 0, engine stop     } if (temps>=2)  { lcd.setCursor(0,0); lcd.print("                "); // Erase line lcd.setCursor(0,0);     lcd.print(Rcy); lcd.setCursor(5,0); ImoteurF=(ImoteurF)/20;     //resistance (5/1024)*(10/0.25ohm) si ACS712 66mV/A                            // For resistance 1ohm (ImoteurF) / 20; Simulation 5/25 lcd.print(ImoteurF); lcd.setCursor(10,0); UmoteurF=UmoteurF*10/38;                              //10/38   10/30 simula if (Umoteur>ImoteurF){UmoteurF=UmoteurF-ImoteurF;  }  //U-R*I lcd.print(UmoteurF); temps=0; }// End if time    } // End loop Since there is a limit of 9000 characters in the forum below Open loop program feature previous The interrupt routine lasts only 250 microseconds, the loop of the main program which scans the action of push buttons is 13micros and the display time of all data is 11ms. Thus, it is possible to improve the sampling period and thus the speed of the regulation of the current. The Arduino makes it possible to make the instrumentation of the scooter so to know the power, the consumption in Ah and Wh, to measure the speed, to know the consumption according to Wh / km, to measure the temperature of the engine, Have a safe operation. But for now we will see how to limit the current 4. Closed loop program, limited current control The sampling period will increase to 0.01 seconds (interrupt routine) If the current is less than the desired value, then the duty cycle can be increased or decreased to the desired value which is the setpoint. On the other hand, if the motor current is greater than the limiting value, there is a rapid decrease in the duty cycle. So as not to exceed the value of the duty cycle if it is saturated to 254 maximum and to the minimum value 6. Code: [Select] if (Imoteur<4000)                    // No current limitation at (20A * 10) * 20 = 4000   {if (consigne>Rcy)   {Rcy=Rcy+1;}   // Pwm ramp + 1 * 0.01second pure integrator    if (consigne    if ( Rcy>254)  {Rcy=254;}           // Limitation of duty cycle    analogWrite(PWM10,Rcy);   // Frequency 32kHz timer2}         } if (Imoteur>4000)  { Rcy=Rcy-5;              // No current filtering, to be faster                     if ( Rcy<6)  {Rcy=5;}       // Rcy is not signed, nor the PWM therefore Rcy minimum must not be less than 6                   analogWrite(PWM10,Rcy);   // Frequency 32kHz timer2}                        } 5. Closed Loop Program, Limited Current Control with Acceleration Handle An acceleration handle provides a 0.8V voltage when not operated and a 4.5V voltage when the handle is fully engaged. Instead of using pushbuttons to increase or decrease the speed setpoint, an acceleration handle will be used Code: [Select] Upoignee=analogRead(A3); // The relation in Upoign and the setpoint which corresponds to the duty cycle corresponds to if (Upoignee>100) { consigne=(Upoignee/2);     //0=a*200+b    et 255=a*800+b                      consigne= consigne-100;                   }                            else { consigne=0;   }               if (Upoignee<100) { consigne=0;  }     // redundancy     6. Temperature and safety program of the motor with the current measurement The outdoor temperature measurement can be easily performed by the LM35 component which charges 0.01V by degrees Celsius Code: [Select] temperature=analogRead(A2); //lm35 0.01V/°C temperature=temperature/2;       // Temperature coefficient lcd.setCursor(5,2); lcd.print("      "); lcd.setCursor(5,2); lcd.print(temperature);   // Display in ° C lcd.setCursor(9,2);      // Erasing secu display lcd.print("     ");   if (temperature>80 ) {lcd.setCursor(9,2);         // If motor external temperature is above 80 ° C                      lcd.print("secuT");                       Rcy=0;} In addition, thermal safety by measuring the motor current will be added. If the limitation current is greater than 10s then the motor will no longer be powered for 30s. A "secu" display will appear on the LCD display. This safety makes it possible to cut the motor on slope too high and when blocking the engine but it would be necessary to add the measurement of the speed in the latter case Code: [Select] if (timesecurite>=10000 ) {flagarret=1;      // If limitation current for a current of more than 10s                               timerepos=0;                               consigne=0;                               Rcy=0;                                 timesecurite=0;}       //   Then stop engine during a downtime    if (flagarret==1 ) {lcd.setCursor(9,2);         // If limiting current for a current of more than 20s                      lcd.print("secU");  }     //   Then stopping the motor for a stop time and display                                                     if (timerepos>=30000 &&  flagarret==1) {flagarret=0;                                           lcd.setCursor(9,2);      // After a rest time here of 30s                                            lcd.print("       ");   }   The display can be observed if the temperature is above 80 ° C Thermal safety by measuring the motor current (digital thermal relay) which allows to know the image of the internal temperature of the engine would be ideal. But for this, it is necessary to know well the thermal modeling of the motor. 7. Measurement of the energy capacity of the battery The energy capacity of a battery is in A.H, we will display the value in mA.H to have a high accuracy. The capacity will be in A.Second in the following equation. So to have in mA.H, it will be divided by capacity by3600. Capacity (A.s) n = I * Te + Cn-1 with Te = 0.01s and I multiplied by 10 So in the interrupt routine Code: [Select] capacity=ImoteurF+capacity ; And in the display Code: [Select] lcd.setCursor(0,3); // Display of energy capacity lcd.print("C mA.h="); capacity1=capacity/(18000);   //18000=3600*5  5=> Current measurement coefficient lcd.print(capacity1); To check a current of 10A with an adjustable resistor and after 30s, the capacity must be 83mA.H 8. Power and modeling with SIMULINK Modeling helps to understand the vehicle and its control. In addition, it is possible to compile the control part directly into the Arduino program from simulation under Simulink. But it will not be possible to simulate the instrumentation with the LCD display. In the following figure, we can observe the simulation of the programming of the chopper with the current limitation with Simulink. In the following figure, the green box shows the duty cycle control to vary the speed and the red border the current limitation. The controller of the control is here a simple integrator but it is possible to carry out a multitude of control. In the previous figure, it can be observed that the current is well limited to 25A from 2s to 9.5s. Then, the current reaches 10.8A under established speed regime at 22.5km / h. The dynamics are similar to the tests carried out. With a slope of 5%, the cyclic ratio reaches only 100% as can be seen in the following figure. The speed will reach painfully 19km / h with a current of 24A and a motor power of 580W. See article: Study of electric scooters 100W and 500W (Arduino), 9. First conclusion It is easy to control a 500W DC motor with an Arduino and some components So repair many scooters that are in DC motors. But it takes some knowledge (automatic, engine) to know how to properly manage the engine and limit its current so as not to damage it The display of the speed, the distance, the operating time to know the / km can also be realized with a menu 2. The .ino program as an attached file, But it is not possible to put an attached file in ISIS electronic labcenter? What is this forum? It would be desirable that the compiler could generate the.cof to debug in Isis and test the program line by line .... Arduino still has to make a lot of effort to be on the same level as other microcontrollers 10. speed measurement (tachometer) Velocity measurement is carried out using a hall effect sensor SS495 or A1324 which counts each revolution of the wheel. It is enough to enter the perimeter of the wheel of the scooter (130mm of radius therefore 0.816m in the case To have the speed, it is enough just to divide the number of turn of wheel on an arbitrary time of 1s to have a minimum speed of 0.81m / s therefore of 2.93 km / h. In addition, an average filter with 3 values will be used to display the speed. At 25km / h, there will be 8.5 laps. To count the turns, an external interrupt routine will be used on input INT0 21 of the mega card. To simulate the speed, a pulse on input 21 will be used with a duty cycle of 10%. Code: [Select] void INT0b21() {   Tspeed++;   // External interruption to count the number of turns } // In the set up declare the interrupt routine when the 5V edge of the magnet detection is done   attachInterrupt(digitalPinToInterrupt(21), INT0b21, RISING );  // External interruption // In loop if (temps09>=5)  {        // 1 second loop lcd.setCursor(13,2);      // Erasing speed lcd.print("kph     "); lcd.setCursor(16,2); speed1=Tspeed*2937;      //1tour*816*3.6/1s=2.937km/h speed2=speed1;           //Tspeed (rate/seconde) speed3=speed2; speedF=(speed1+speed2+speed3)/3000;   // To put in kph lcd.print(speedF,1);    // Display to the nearest tenth Tspeed=0;   // Reset counter temps09=0;  //reset time } To improve the accuracy of the velocity measurement, it is possible that the sampling time of the velocity measurement is dependent on the velocity. For example: For speeds less than 10km / h sample at 1second, but above 10km / h sample at 2 seconds. 11. Distance measurement for autonomy The distance corresponds to the total number of turns of the wheel multiplied by the perimeter of the wheel. So do not set the number of turns to 0 for each sample. On the other hand, the reset of the distance will be done when pressing the reset of the Arduino Mega. The distance display will be displayed to the nearest second. At 32km / h, it will take 2 minutes to do 1km as can be seen in the following figure: Code: [Select] void INT0b21() {   Tspeed++;   // External interruption to count speed   nbrRate++; } lcd.setCursor(13,4);      lcd.print("km      ");  // distance=(nbrRate*816)/1000;  //distance m distance=distance/1000;  //distance km lcd.setCursor(15,4);      lcd.print(distance,1);  You can observe the electrical installation with the chopper, the arduino, and the display when the program is set up 12. Synthesis The RAM space is used only at 4% and ROM space at 3%, for an Arduino mega. So we could take an arduino a little smaller. But, there are 8 Lipo cells to make the 24V power supply to power the engine via the chopper. Therefore, the voltage measurement of each element will be on the Arduino with a JST connector. This measurement makes it possible to know if a cell with an internal resistance which begins to pose a problem and to know if the balancing of each cell has indeed been carried out. It is possible to switch to 36V with 12 cells also with the arduino mega without using an external shield that multiplex 24 analog inputs on input A0 It is possible to send all data to a smartphone via Bluetooth HC06 via pins 20, 21, RX1 and TX1. But the application under android realized under JAVA Studio can not be shared on this forum. This part will not be explained. After having made the instrumentation of this scooter, a study should be carried out on the precision of the measurements, it is possible to read "Instrumentation of a low-power electrical motor vehicle" eco marathon "type Revue 3EI N ° 81, July 2015

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