NZD New Zealand Dollar Latest News, Analysis and Forex. Latest NZD market news, analysis and New Zealand Dollar trading forecast. NATURA AMORE ARTE ANIMALI CITT NATALIZI RICORRENZE PAESAGGI FIORI VARIE Dipinto di Salvador Domnec Felip Jacint Dal, Olio su Tela Noia alla finestra. Driving 5 Speakers Simultaneously with an Arduino. This post was featured on the Hack a Day Blog on 91. You can download a C code rewrite of this code, here. Mimi Yin has a neat implementation of this code for an interactive sculpture. Facebook Account Hacker V3 Anderson Education' title='Facebook Account Hacker V3 Anderson Education' />For the Reac. Xion AudioVisual Project Ive been working on, its necessary to drive 5 speakers independently each with a variable volume and set frequency though the frequency of each speaker is different. I examined several methods for generating the 5 square waves in hardware using a 5. RC with schmitt trigger, and a bunch of opamp circuits. Unfortunately, none of these generated tones as nice as the ones I got when simply using the arduino tone library. The built in tone function allows you to generate a squarewave with 5. It relies on one of the arduinos 3 timers to work in the background. Specifically, it uses timer. PWM on pins 3 and 1. So you naturally loose that ability when using the tone function. But I wanted to make 5 tones simultaneouslyA news and discussion site for those interested in robots and robotics. Home of the Robot Competition FAQ and a variety of resource pages. How to do it While the tone function can only be run one instance at a time, I discovered after much research, that I could hijack one of the timers again, I chose timer. I wanted to generate 5 tones of the following frequencies C 1. Hz. D 1. 47 Hz. E 1. Hz. G 1. Hz. A 2. Hz. Any music lovers out there will surely recognize this as the pentatonic scale 5 notes that nearly always sound good together. Now, think back to physics, and recall that period 1frequency. In other words, each frequency pin will have to cycle from 0. V to 5. V and back again in the time dictated by the period for that note. See the following picture The red portion of the square wave represents one cycle. From the formula above, we can determine the following periods required to generate each note C 11. Rac Installation Steps In Oracle 10G Database. Hz 7. 6ms. D 11. Hz 6. E 11. Hz 6. 0ms. G 11. Hz 5. 1ms. A 12. Hz 4. But, remember that we are dealing with a microcontroller, so we need to flip the value twice every period. If you take a look at the green portions on the image above youll see what Im talking about. In one red portion of the wave, the value needs to change twice. So in reality, we actually need to be able to flip bits twice as fast as the times outlined above. Dividing those values by two, we get the following C 7. D 6. 8ms2 3. E 6. G 5. 1ms2 2. A 4. So, if we want to generate all these tones at the same time, were going to need to have an interrupt service that can activate at a Greatest Common Factor for all these values. This interrupt request will toggle the appropriate pin every prescribed number of milliseconds, and well get the tones we needSo, the least common multiple for the variables above would be. If we use this ideal value, we can construct an interrupt service request that will initiate every 5. Using some counters, we can flip the bits after the appropriate intervals Lets calculate those counters now C 3. D 3. 4. 0ms5. 0s 6. E 3. 0. 0ms5. 0s 6. G 2. 5. 5ms5. 0s 5. A 2. 2. 5ms5. 0s 4. In an ideal world, we would simply have a software interrupt trigger every 5. For example, every time counter. If the only thing you were doing with your CPU was making noises, then this would work quite well. But the whole reason for doing this in an interrupt routine is so that we can do other things simultaneously. For this project, Im simultaneously controlling a large LED matrix. If the matrix isnt refreshed often enough, the display looks choppy. Unfortunately, cutting away to an interrupt routine every 5. So, I had no choice but to trade off some frequency accuracy for a reduction in how often I activated the interrupt. After some trial and error, I deemed the golden value to be 6. Its a little more than the ideal lowest common denominator, but still close enough that the notes sound good. Using this new value, I calculated new counts, and implemented them in my interrupt routine C 3. D 3. 4. 0ms6. 4s 5. E 3. 0. 0ms6. 4s 4. G 2. 5. 5ms6. 4s 4. A 2. 2. 5ms6. 4s 3. And thats it Using these values, I can simultaneously generate all five notes, while maintaining enough time to quickly update my LED Matrix. Below is the final arduino code for making this work. Thanks to Sebastian Wallin for some awesome information on interfacing with arduino timer interrupts. Licensed via Creative Commons Attribution Non. Commercial Share. Alike 3. 0 Unported License Categories Assorted Hacks and Mods, Ramblings. Tags arduino, frequency, hackaday, reac. Xion, speakers, timers. Robot news and Robotics Info. I made the first post on Robots. February 2. 00. 1. Since then, rog a matic, The Swirling Brain, and steve have written more than 3. You probably noticed we took a bit of a break the last year or so thanks to the Robot Podcast crew for keeping the news going during that time. Lately weve been evaluating whether to do a reboot and start posting again or retire the blog. Today you can get robot news everywhere, so theres not as a much of a need for our specialized reporting. Also, we relied heavily on income from Google ads to pay for all this but the days of making money that way are long gone. So, as much as I still love talking about robots, I think weve come to the end of our long, robotic road. As Jerzy said at the end of Rudy Ruckers The Hacker and the Ants, The robots were out in the world and doing fine. Id done enough for the robots. But maybe youd like to pick up where we left off Were open to the possibility of selling the site or even just the domain. Let us know if youre interested.