LeafLabs Garden » Topic: Throbbing LED maple R5

LeafLabs Garden » Topic: Throbbing LED maple R5 http://forums.leaflabs.com/topic.php?id=13139 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:17:35 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://forums.leaflabs.com/search.php pyrohaz on "Throbbing LED maple R5" http://forums.leaflabs.com/topic.php?id=13139#post-28312 Tue, 06 Aug 2013 15:10:56 +0000 pyrohaz 28312@http://forums.leaflabs.com/ Well! Sorry for the late reply. I've finally had the opportunity to test out this code and can safely say that its fully working! By decimating each bin from 8 bit down to 3 bit, then shifting up 5 bits and subtracting 1 (ensuring that 0 bins are 0 with a simple if), I have made a graphic analyzer! Its really interesting to learn about this sorta stuff, so now i've done a standard fourier transform, whats next within the field of frequency domain transformation? mlundinse on "Throbbing LED maple R5" http://forums.leaflabs.com/topic.php?id=13139#post-28138 Tue, 30 Jul 2013 08:36:54 +0000 mlundinse 28138@http://forums.leaflabs.com/ There are some problems here that results in the throbbig error light, that is probably caused by array indices gone haywire. First you must initialise your loop variables. <pre><code>for(int WaveWrite; WaveWrite<256; WaveWrite++){</code></pre> should be <pre><code>for(int WaveWrite = 0; WaveWrite<256; WaveWrite++){</code></pre> The delay of 1000 after starting the sample timer results in the program trying to read 18000 samples, overflowing available RAM and crashing. The NextSamples flag alone is not a reliable way to stop sampling after exact 256 samples, there is no way to be sure that this flag is cleared without delay after the 256'th sample has been read. The main loop can be busy waiting for the I/O buffers to clear. Instead set NextSamples to 0 in the sampling interrupt after the last sample has been read. <pre><code>void Sampling(){ //Samples done here if(NextSamples==1){ SampleRead = (analogRead(0) - MidP)>>4; //Sample and subtract midpoint(constant), shift to 8 bit range Sample[SampCount] = SampleRead; //Store samples in array SampCount++; //Increment sample counter if (SampCount<=256) NextSamples = 0; //Stop sampling until buffer handled by loop() } }</code></pre> Another method is to stop the timer in the sampling interrupt after the last sample, and restart it when the FT has been calculated. ala42 on "Throbbing LED maple R5" http://forums.leaflabs.com/topic.php?id=13139#post-28137 Tue, 30 Jul 2013 08:27:20 +0000 ala42 28137@http://forums.leaflabs.com/ You should change if(NextSamples==1){ to if(SampCount<256){ Otherwise you will overwrite your sample array in the main loop is not fast enough. pyrohaz on "Throbbing LED maple R5" http://forums.leaflabs.com/topic.php?id=13139#post-28105 Mon, 29 Jul 2013 21:01:48 +0000 pyrohaz 28105@http://forums.leaflabs.com/ Hey guys, I've got a new project: I recently received another 8x8 matrix LED display, powered by the Maxim MAX7219 chip, it works fine with the LED control library. What i'm having a go at is a really simple graphic equalizer. Now I don't actually do any formal studying of electronics or mathematics so please bare with my lack of ability! I know of the fourier transform so i'm merely going off my knowledge of that and i've written this code: <code> #include <math.h> volatile int16 Sample[256], SampleRead, SampCount; int16 Wa1[256], Wa2[256], Wa3[256], Wa4[256], Wa5[256], Wa6[256], Wa7[256], Wa8[256]; int16 MidP, NextSamples = 1; double SineD = 0; byte Fv = 127; int16 Bin1, Bin2, Bin3, Bin4, Bin5, Bin6, Bin7, Bin8; HardwareTimer SampleTimer(2); void setup(){ SerialUSB.begin(); SampleTimer.pause(); //Create Sine wave arrays for(int WaveWrite; WaveWrite<256; WaveWrite++){ Wa1[WaveWrite] = 127*sin(SineD); //~70Hz Wa2[WaveWrite] = 127*sin(SineD*2); //~141Hz Wa3[WaveWrite] = 127*sin(SineD*4); //~281Hz Wa4[WaveWrite] = 127*sin(SineD*8); //~563Hz Wa5[WaveWrite] = 127*sin(SineD*16); //1125Hz Wa6[WaveWrite] = 127*sin(SineD*32); //2250Hz Wa7[WaveWrite] = 127*sin(SineD*64); //4500Hz Wa8[WaveWrite] = Fv; //9000Hz SineD+=0.024544; Fv*=-1; } pinMode(0, INPUT_ANALOG); //Analog Input (mid biased 2x 1k resistors) adc_set_sample_rate(ADC1, ADC_SMPR_1_5); //Fastest sampling rate //Sample rate of 18KHz SampleTimer.setPrescaleFactor(1); SampleTimer.setOverflow(3999); SampleTimer.setChannel1Mode(TIMER_OUTPUT_COMPARE); SampleTimer.setCompare(TIMER_CH1, 1); SampleTimer.attachCompare1Interrupt(Sampling); SampleTimer.refresh(); SampleTimer.resume(); delay(1000); MidP = analogRead(0); //Find mid point of circuit, no audio applied } void loop(){ if(SampCount>=255){ NextSamples = 0; //Stop more samples being processor //Compute FT, multiply all sine tables by samples and sum to store in bin(s) for(int FT = 0; FT<256; FT++){ Bin1 += (Sample[FT]*Wa1[FT]); Bin2 += (Sample[FT]*Wa2[FT]); Bin3 += (Sample[FT]*Wa3[FT]); Bin4 += (Sample[FT]*Wa4[FT]); Bin5 += (Sample[FT]*Wa5[FT]); Bin6 += (Sample[FT]*Wa6[FT]); Bin7 += (Sample[FT]*Wa7[FT]); Bin8 += (Sample[FT]*Wa8[FT]); } //Magnitude of bins, shift to 8bit range Bin1 = (abs(Bin1))>>7; Bin2 = (abs(Bin2))>>7; Bin3 = (abs(Bin3))>>7; Bin4 = (abs(Bin4))>>7; Bin5 = (abs(Bin5))>>7; Bin6 = (abs(Bin6))>>7; Bin7 = (abs(Bin7))>>7; Bin8 = (abs(Bin8))>>7; SampCount = 0; //Reset sample counter NextSamples = 1; //Start next set of samples } else{ //While the FT isn't being calculated, print bins, debug only SerialUSB.print(Bin1); SerialUSB.print(" "); SerialUSB.print(Bin2); SerialUSB.print(" "); SerialUSB.print(Bin3); SerialUSB.print(" "); SerialUSB.print(Bin4); SerialUSB.print(" "); SerialUSB.print(Bin5); SerialUSB.print(" "); SerialUSB.print(Bin6); SerialUSB.print(" "); SerialUSB.print(Bin7); SerialUSB.print(" "); SerialUSB.println(Bin8); } } void Sampling(){ //Samples done here if(NextSamples==1){ SampleRead = (analogRead(0) - MidP)>>4; //Sample and subtract midpoint(constant), shift to 8 bit range Sample[SampCount] = SampleRead; //Store samples in array SampCount++; //Increment sample counter } } </code><code> As you can see, its creating 8 sine wave arrays of different frequencies in the setup and once a full 256 array of samples has been done, carrying out a real only fourier transform on the sample array (no phase). What I then want to do with the 8 bins is convert them into 3 bit values to then be used to drive my graphic LED. The only problem i'm having is when I upload this code, the LED on my maple just throbs at me and it doesn't want to do anything. What seems to be wrong with my code and how can I fix it? I've tried replacing the "next samples" section for timer pause and refresh/resume but this still caused the throbbing LED problem. My maple still works as I can upload the blink program successfully. Thanks, Harris</code>