├── ArduinoSoundLevelMeter.ino ├── LICENSE └── README.md /ArduinoSoundLevelMeter.ino: -------------------------------------------------------------------------------- 1 | #include 2 | 3 | // FHT, http://wiki.openmusiclabs.com/wiki/ArduinoFHT 4 | #define LOG_OUT 1 // use the log output function 5 | #define LIN_OUT8 1 // use the linear byte output function 6 | #define FHT_N 256 // set to 256 point fht 7 | #include // include the library 8 | 9 | // pins 10 | #define MicPin A0 // used with analogRead mode only 11 | 12 | // consts 13 | #define AmpMax (1024 / 2) 14 | #define MicSamples (1024*2) // Three of these time-weightings have been internationally standardised, 'S' (1 s) originally called Slow, 'F' (125 ms) originally called Fast and 'I' (35 ms) originally called Impulse. 15 | 16 | // modes 17 | #define Use3.3 // use 3.3 voltage. the 5v voltage from usb is not regulated. this is much more stable. 18 | #define ADCReClock // switch to higher clock, not needed if we are ok with freq between 0 and 4Khz. 19 | #define ADCFlow // read data from adc with free-run (not interupt). much better data, dc low. hardcoded for A0. 20 | 21 | #define FreqLog // use log scale for FHT frequencies 22 | #ifdef FreqLog 23 | #define FreqOutData fht_log_out 24 | #define FreqGainFactorBits 0 25 | #else 26 | #define FreqOutData fht_lin_out8 27 | #define FreqGainFactorBits 3 28 | #endif 29 | #define FreqSerialBinary 30 | 31 | #define VolumeGainFactorBits 0 32 | 33 | // macros 34 | // http://yaab-arduino.blogspot.co.il/2015/02/fast-sampling-from-analog-input.html 35 | #define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit)) 36 | #define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit)) 37 | 38 | // LCD 39 | LiquidCrystal lcd(9, 8, 7, 6, 5, 4); 40 | char lcdLineBuf[16 + 1]; 41 | 42 | void setup() 43 | { 44 | //pinMode(MicPin, INPUT); // relevant for digital pins. not relevant for analog. however, don't put into digital OUTPUT mode if going to read analog values. 45 | 46 | #ifdef ADCFlow 47 | // set the adc to free running mode 48 | // register explanation: http://maxembedded.com/2011/06/the-adc-of-the-avr/ 49 | // 5 => div 32. sample rate 38.4 50 | // 7 => switch to divider=128, default 9.6khz sampling 51 | ADCSRA = 0xe0+7; // "ADC Enable", "ADC Start Conversion", "ADC Auto Trigger Enable" and divider. 52 | ADMUX = 0x0; // use adc0 (hardcoded, doesn't use MicPin). Use ARef pin for analog reference (same as analogReference(EXTERNAL)). 53 | #ifndef Use3.3 54 | ADMUX |= 0x40; // Use Vcc for analog reference. 55 | #endif 56 | DIDR0 = 0x01; // turn off the digital input for adc0 57 | #else 58 | #ifdef Use3.3 59 | analogReference(EXTERNAL); // 3.3V to AREF 60 | #endif 61 | #endif 62 | 63 | #ifdef ADCReClock // change ADC freq divider. default is div 128 9.6khz (bits 111) 64 | // http://yaab-arduino.blogspot.co.il/2015/02/fast-sampling-from-analog-input.html 65 | // 1 0 0 = mode 4 = divider 16 = 76.8khz 66 | //sbi(ADCSRA, ADPS2); 67 | //cbi(ADCSRA, ADPS1); 68 | //cbi(ADCSRA, ADPS0); 69 | // 1 0 1 = mode 5 = divider 32 = 38.4Khz 70 | sbi(ADCSRA, ADPS2); 71 | cbi(ADCSRA, ADPS1); 72 | sbi(ADCSRA, ADPS0); 73 | #endif 74 | 75 | // serial 76 | Serial.begin(9600); 77 | while (!Serial); // Wait untilSerial is ready - Leonardo 78 | Serial.println("Starting mic demo"); 79 | 80 | // lcd 81 | lcd.begin(16, 2); // set up the LCD's number of columns and rows: 82 | lcd.clear(); //Clears the LCD screen and positions the cursor in the upper-left corner. 83 | lcd.setCursor(0, 0); // set the cursor to column 6, line 0 84 | lcd.print("Sound: "); 85 | } 86 | 87 | void loop() 88 | { 89 | // what do we want to do? 90 | //MeasureAnalog(); 91 | MeasureVolume(); 92 | //MeasureFHT(); 93 | } 94 | 95 | // measure basic properties of the input signal 96 | // determine if analog or digital, determine range and average. 97 | void MeasureAnalog() 98 | { 99 | long signalAvg = 0, signalMax = 0, signalMin = 1024, t0 = millis(); 100 | //cli(); // UDRE interrupt slows this way down on arduino1.0 101 | for (int i = 0; i < MicSamples; i++) 102 | { 103 | #ifdef ADCFlow 104 | while (!(ADCSRA & /*0x10*/_BV(ADIF))); // wait for adc to be ready (ADIF) 105 | sbi(ADCSRA, ADIF); // restart adc 106 | byte m = ADCL; // fetch adc data 107 | byte j = ADCH; 108 | int k = ((int)j << 8) | m; // form into an int 109 | #else 110 | int k = analogRead(MicPin); 111 | #endif 112 | signalMin = min(signalMin, k); 113 | signalMax = max(signalMax, k); 114 | signalAvg += k; 115 | } 116 | signalAvg /= MicSamples; 117 | //sei(); 118 | 119 | // print 120 | Serial.print("Time: " + String(millis() - t0)); 121 | Serial.print(" Min: " + String(signalMin)); 122 | Serial.print(" Max: " + String(signalMax)); 123 | Serial.print(" Avg: " + String(signalAvg)); 124 | Serial.print(" Span: " + String(signalMax - signalMin)); 125 | Serial.print(", " + String(signalMax - signalAvg)); 126 | Serial.print(", " + String(signalAvg - signalMin)); 127 | Serial.println(""); 128 | 129 | //lcd.clear(); //Clears the LCD screen and positions the cursor in the upper-left corner. 130 | //lcd.setCursor(6, 0); // set the cursor to column 0, line 0 131 | //sprintf(lcdLineBuf, "%3d%% %3ddB", (int)soundVolRMS, (int)dB); 132 | //lcd.print(lcdLineBuf); 133 | } 134 | 135 | // calculate volume level of the signal and print to serial and LCD 136 | void MeasureVolume() 137 | { 138 | long soundVolAvg = 0, soundVolMax = 0, soundVolRMS = 0, t0 = millis(); 139 | //cli(); // UDRE interrupt slows this way down on arduino1.0 140 | for (int i = 0; i < MicSamples; i++) 141 | { 142 | #ifdef ADCFlow 143 | while (!(ADCSRA & /*0x10*/_BV(ADIF))); // wait for adc to be ready (ADIF) 144 | sbi(ADCSRA, ADIF); // restart adc 145 | byte m = ADCL; // fetch adc data 146 | byte j = ADCH; 147 | int k = ((int)j << 8) | m; // form into an int 148 | #else 149 | int k = analogRead(MicPin); 150 | #endif 151 | int amp = abs(k - AmpMax); 152 | amp <<= VolumeGainFactorBits; 153 | soundVolMax = max(soundVolMax, amp); 154 | soundVolAvg += amp; 155 | soundVolRMS += ((long)amp*amp); 156 | } 157 | soundVolAvg /= MicSamples; 158 | soundVolRMS /= MicSamples; 159 | float soundVolRMSflt = sqrt(soundVolRMS); 160 | //sei(); 161 | 162 | float dB = 20.0*log10(soundVolRMSflt/AmpMax); 163 | 164 | // convert from 0 to 100 165 | soundVolAvg = 100 * soundVolAvg / AmpMax; 166 | soundVolMax = 100 * soundVolMax / AmpMax; 167 | soundVolRMSflt = 100 * soundVolRMSflt / AmpMax; 168 | soundVolRMS = 10 * soundVolRMSflt / 7; // RMS to estimate peak (RMS is 0.7 of the peak in sin) 169 | 170 | // print 171 | Serial.print("Time: " + String(millis() - t0)); 172 | Serial.print(" Amp: Max: " + String(soundVolMax)); 173 | Serial.print("% Avg: " + String(soundVolAvg)); 174 | Serial.print("% RMS: " + String(soundVolRMS)); 175 | Serial.println("% dB: " + String(dB,3)); 176 | 177 | //lcd.clear(); //Clears the LCD screen and positions the cursor in the upper-left corner. 178 | lcd.setCursor(6, 0); // set the cursor to column 6, line 0 179 | sprintf(lcdLineBuf, "%3d%% %3ddB", (int)soundVolRMS, (int)dB); 180 | lcd.print(lcdLineBuf); 181 | 182 | } 183 | 184 | // calculate frequencies in the signal and print to serial 185 | void MeasureFHT() 186 | { 187 | long t0 = micros(); 188 | #ifdef ADCFlow 189 | //cli(); // UDRE interrupt slows this way down on arduino1.0 190 | #endif 191 | for (int i = 0; i < FHT_N; i++) { // save 256 samples 192 | #ifdef ADCFlow 193 | while (!(ADCSRA & /*0x10*/_BV(ADIF))); // wait for adc to be ready (ADIF) 194 | sbi(ADCSRA, ADIF); // restart adc 195 | byte m = ADCL; // fetch adc data 196 | byte j = ADCH; 197 | int k = ((int)j << 8) | m; // form into an int 198 | #else 199 | int k = analogRead(MicPin); 200 | #endif 201 | k -= 0x0200; // form into a signed int 202 | k <<= 6; // form into a 16b signed int 203 | k <<= FreqGainFactorBits; 204 | fht_input[i] = k; // put real data into bins 205 | } 206 | #ifdef ADCFlow 207 | //sei(); 208 | #endif 209 | long dt = micros() - t0; 210 | fht_window(); // window the data for better frequency response 211 | fht_reorder(); // reorder the data before doing the fht 212 | fht_run(); // process the data in the fht 213 | #ifdef FreqLog 214 | fht_mag_log(); 215 | #else 216 | fht_mag_lin8(); // take the output of the fht 217 | #endif 218 | 219 | #ifdef FreqSerialBinary 220 | // print as binary 221 | Serial.write(255); // send a start byte 222 | Serial.write(FreqOutData, FHT_N / 2); // send out the data 223 | #else 224 | // print as text 225 | for (int i = 0; i < FHT_N / 2; i++) 226 | { 227 | Serial.print(FreqOutData[i]); 228 | Serial.print(','); 229 | } 230 | long sample_rate = FHT_N * 1000000l / dt; 231 | Serial.print(dt); 232 | Serial.print(','); 233 | Serial.println(sample_rate); 234 | #endif 235 | } 236 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. Definitions. 8 | 9 | "License" shall mean the terms and conditions for use, reproduction, 10 | and distribution as defined by Sections 1 through 9 of this document. 11 | 12 | "Licensor" shall mean the copyright owner or entity authorized by 13 | the copyright owner that is granting the License. 14 | 15 | "Legal Entity" shall mean the union of the acting entity and all 16 | other entities that control, are controlled by, or are under common 17 | control with that entity. For the purposes of this definition, 18 | "control" means (i) the power, direct or indirect, to cause the 19 | direction or management of such entity, whether by contract or 20 | otherwise, or (ii) ownership of fifty percent (50%) or more of the 21 | outstanding shares, or (iii) beneficial ownership of such entity. 22 | 23 | "You" (or "Your") shall mean an individual or Legal Entity 24 | exercising permissions granted by this License. 25 | 26 | "Source" form shall mean the preferred form for making modifications, 27 | including but not limited to software source code, documentation 28 | source, and configuration files. 29 | 30 | "Object" form shall mean any form resulting from mechanical 31 | transformation or translation of a Source form, including but 32 | not limited to compiled object code, generated documentation, 33 | and conversions to other media types. 34 | 35 | "Work" shall mean the work of authorship, whether in Source or 36 | Object form, made available under the License, as indicated by a 37 | copyright notice that is included in or attached to the work 38 | (an example is provided in the Appendix below). 39 | 40 | "Derivative Works" shall mean any work, whether in Source or Object 41 | form, that is based on (or derived from) the Work and for which the 42 | editorial revisions, annotations, elaborations, or other modifications 43 | represent, as a whole, an original work of authorship. For the purposes 44 | of this License, Derivative Works shall not include works that remain 45 | separable from, or merely link (or bind by name) to the interfaces of, 46 | the Work and Derivative Works thereof. 47 | 48 | "Contribution" shall mean any work of authorship, including 49 | the original version of the Work and any modifications or additions 50 | to that Work or Derivative Works thereof, that is intentionally 51 | submitted to Licensor for inclusion in the Work by the copyright owner 52 | or by an individual or Legal Entity authorized to submit on behalf of 53 | the copyright owner. For the purposes of this definition, "submitted" 54 | means any form of electronic, verbal, or written communication sent 55 | to the Licensor or its representatives, including but not limited to 56 | communication on electronic mailing lists, source code control systems, 57 | and issue tracking systems that are managed by, or on behalf of, the 58 | Licensor for the purpose of discussing and improving the Work, but 59 | excluding communication that is conspicuously marked or otherwise 60 | designated in writing by the copyright owner as "Not a Contribution." 61 | 62 | "Contributor" shall mean Licensor and any individual or Legal Entity 63 | on behalf of whom a Contribution has been received by Licensor and 64 | subsequently incorporated within the Work. 65 | 66 | 2. Grant of Copyright License. Subject to the terms and conditions of 67 | this License, each Contributor hereby grants to You a perpetual, 68 | worldwide, non-exclusive, no-charge, royalty-free, irrevocable 69 | copyright license to reproduce, prepare Derivative Works of, 70 | publicly display, publicly perform, sublicense, and distribute the 71 | Work and such Derivative Works in Source or Object form. 72 | 73 | 3. Grant of Patent License. Subject to the terms and conditions of 74 | this License, each Contributor hereby grants to You a perpetual, 75 | worldwide, non-exclusive, no-charge, royalty-free, irrevocable 76 | (except as stated in this section) patent license to make, have made, 77 | use, offer to sell, sell, import, and otherwise transfer the Work, 78 | where such license applies only to those patent claims licensable 79 | by such Contributor that are necessarily infringed by their 80 | Contribution(s) alone or by combination of their Contribution(s) 81 | with the Work to which such Contribution(s) was submitted. If You 82 | institute patent litigation against any entity (including a 83 | cross-claim or counterclaim in a lawsuit) alleging that the Work 84 | or a Contribution incorporated within the Work constitutes direct 85 | or contributory patent infringement, then any patent licenses 86 | granted to You under this License for that Work shall terminate 87 | as of the date such litigation is filed. 88 | 89 | 4. Redistribution. You may reproduce and distribute copies of the 90 | Work or Derivative Works thereof in any medium, with or without 91 | modifications, and in Source or Object form, provided that You 92 | meet the following conditions: 93 | 94 | (a) You must give any other recipients of the Work or 95 | Derivative Works a copy of this License; and 96 | 97 | (b) You must cause any modified files to carry prominent notices 98 | stating that You changed the files; and 99 | 100 | (c) You must retain, in the Source form of any Derivative Works 101 | that You distribute, all copyright, patent, trademark, and 102 | attribution notices from the Source form of the Work, 103 | excluding those notices that do not pertain to any part of 104 | the Derivative Works; and 105 | 106 | (d) If the Work includes a "NOTICE" text file as part of its 107 | distribution, then any Derivative Works that You distribute must 108 | include a readable copy of the attribution notices contained 109 | within such NOTICE file, excluding those notices that do not 110 | pertain to any part of the Derivative Works, in at least one 111 | of the following places: within a NOTICE text file distributed 112 | as part of the Derivative Works; within the Source form or 113 | documentation, if provided along with the Derivative Works; or, 114 | within a display generated by the Derivative Works, if and 115 | wherever such third-party notices normally appear. The contents 116 | of the NOTICE file are for informational purposes only and 117 | do not modify the License. You may add Your own attribution 118 | notices within Derivative Works that You distribute, alongside 119 | or as an addendum to the NOTICE text from the Work, provided 120 | that such additional attribution notices cannot be construed 121 | as modifying the License. 122 | 123 | You may add Your own copyright statement to Your modifications and 124 | may provide additional or different license terms and conditions 125 | for use, reproduction, or distribution of Your modifications, or 126 | for any such Derivative Works as a whole, provided Your use, 127 | reproduction, and distribution of the Work otherwise complies with 128 | the conditions stated in this License. 129 | 130 | 5. Submission of Contributions. Unless You explicitly state otherwise, 131 | any Contribution intentionally submitted for inclusion in the Work 132 | by You to the Licensor shall be under the terms and conditions of 133 | this License, without any additional terms or conditions. 134 | Notwithstanding the above, nothing herein shall supersede or modify 135 | the terms of any separate license agreement you may have executed 136 | with Licensor regarding such Contributions. 137 | 138 | 6. Trademarks. This License does not grant permission to use the trade 139 | names, trademarks, service marks, or product names of the Licensor, 140 | except as required for reasonable and customary use in describing the 141 | origin of the Work and reproducing the content of the NOTICE file. 142 | 143 | 7. Disclaimer of Warranty. Unless required by applicable law or 144 | agreed to in writing, Licensor provides the Work (and each 145 | Contributor provides its Contributions) on an "AS IS" BASIS, 146 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or 147 | implied, including, without limitation, any warranties or conditions 148 | of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A 149 | PARTICULAR PURPOSE. You are solely responsible for determining the 150 | appropriateness of using or redistributing the Work and assume any 151 | risks associated with Your exercise of permissions under this License. 152 | 153 | 8. Limitation of Liability. In no event and under no legal theory, 154 | whether in tort (including negligence), contract, or otherwise, 155 | unless required by applicable law (such as deliberate and grossly 156 | negligent acts) or agreed to in writing, shall any Contributor be 157 | liable to You for damages, including any direct, indirect, special, 158 | incidental, or consequential damages of any character arising as a 159 | result of this License or out of the use or inability to use the 160 | Work (including but not limited to damages for loss of goodwill, 161 | work stoppage, computer failure or malfunction, or any and all 162 | other commercial damages or losses), even if such Contributor 163 | has been advised of the possibility of such damages. 164 | 165 | 9. Accepting Warranty or Additional Liability. While redistributing 166 | the Work or Derivative Works thereof, You may choose to offer, 167 | and charge a fee for, acceptance of support, warranty, indemnity, 168 | or other liability obligations and/or rights consistent with this 169 | License. However, in accepting such obligations, You may act only 170 | on Your own behalf and on Your sole responsibility, not on behalf 171 | of any other Contributor, and only if You agree to indemnify, 172 | defend, and hold each Contributor harmless for any liability 173 | incurred by, or claims asserted against, such Contributor by reason 174 | of your accepting any such warranty or additional liability. 175 | 176 | END OF TERMS AND CONDITIONS 177 | 178 | APPENDIX: How to apply the Apache License to your work. 179 | 180 | To apply the Apache License to your work, attach the following 181 | boilerplate notice, with the fields enclosed by brackets "{}" 182 | replaced with your own identifying information. (Don't include 183 | the brackets!) The text should be enclosed in the appropriate 184 | comment syntax for the file format. We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright {yyyy} {name of copyright owner} 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # ArduinoSoundLevelMeter 2 | A demo of sound measurement and processing in Arduino 3 | 4 | See the article "Arduino sound level meter and spectrum analyzer" at http://blog.yavilevich.com/2016/08/arduino-sound-level-meter-and-spectrum-analyzer/ for more info. --------------------------------------------------------------------------------