A basic soundboard design options? - Page 1
Forum section: electronics / projects

author: ceecrb1
author_rank: Contributor
timestamp: January 22, 2013, 08:13:50 pm
content: Just wondering what people would recomend as the best option for a device I would like to replace..The back story is that there are some childs "games" at a cinema complex.There is a button which connects via a relay to a sound player... the sound player which is connected to a small power amplifier also has a relay output which ativates a strobe.So the final effect is that you press a button and get a 2 second or so sound clip (the fart one seems to be a favourite) and a strobe flashes.In total we have 8 buttons, and 2 rackmount units which control 4 buttons each.. well one of these units has given up and gone on permanent strike after about 14 years of service...A replacement quote came in at over 3000 USD!!!!!!!!Surely this would be far cheaper and in todays world easy enough to do with something can make, I guess rasperrypi would be the easiest for me as I just did the core of electrical engineering and computer science, so it leans towards my programming style.... but I get the feeling I should be able to get it going on an arduino?? I've never used or seen in my hands either.. or any other similar product so in the dark a little.Ideas? Comments? Suggestions?Luckily I have all the original audio clips on WAV so can build anything and the end result would be identical and nobody would knowUnfortunately for speed the client has reluctantly had to pay the cash and get the parts ordered.. so as the 2nd unit has the same age.. we are expecting it to possibly be on its last legs too.. so I could at least do the work to get one going and when the 2nd unit goes... just order others and "copy n paste".So basic Idea..Recieve input from a relay (cant remeber if press is high or low) and play a sound and also activate a nother relay to give the strobe controller a short circuit so its activated.... pretty simple really,.

author: mamalala
author_rank: Unknown
timestamp: January 22, 2013, 08:40:45 pm
content: A while back i built an MP3 playback circuit for an art project (well, the MP3 section was just a part of it). You can use a SD card, a VS1011 MP3 player chip, and a tiny microcontroller.The basic idea is that you store the sound data at fixed start (block) addresses on the SD card (i.e. there is no file system on the card, just raw access). Using the SD card in 1-bit mode, you connect the data line to the data-in of the VS1011. All that the µC needs to do is to address the SD card blocks, clock the data out, while enabling the VS chip during the times when actual data is transferred out of the SD. Basically it streams directly from the card into the chip.This allows the use of a rather small µC to control all that. You can prepare the SD card by simply copying the data into one big file (padding each soundfile with zeros to have it use whole block sizes), and then raw write the resulting data to the card.The VS1011 is from VLSI:http://www.vlsi.fi/en/products/vs1011.htmlGreetings,Chris

author: nctnico
author_rank: Super Contributor
timestamp: January 22, 2013, 09:06:01 pm
content: Actually its not very difficult to use a FAT16 or FAT32 filesystem. I've used this software:http://elm-chan.org/fsw/ff/00index_e.htmlon an LPC2000 controller with 32kB of flash for a project for a customer. I've given it some thourough testing (lots of reading and writing) and it seems to hold. The advantage is that you can drag & drop files onto the SD card with Windows or Linux.

author: mamalala
author_rank: Unknown
timestamp: January 22, 2013, 09:20:27 pm
content: Quote from: nctnico on January 22, 2013, 09:06:01 pmTrue, using a filesystem makes data transfer easier, but it also adds complexity. I guess it's all a matter how simple should be. In my case i also had to use a RF transmitter (the installation consisted of multiple such boards, controlled by a central computer), and a rather small PIC µC to glue it all together. The advantage here was that most of the time i only had to supply a clock to the SD/VS combination to keep it going, while at the same time i could fully handle the RF protocol without interruption.Again, it's all a matter of how complex things should/can be. If the smallest effort and complexity is wanted, that "direct" method works pretty well. If more flexibility is needed and a bigger µC possible, a true filesystem is the way to go.BTW, an even simpler method is to use a flash memory chip with parallel interface, a bunch of 74HC counters and latches, plus a simple R-2R DAC. Connect the DAC to the 8-bit data out of the flash, and the counters/latches to the address lines. Have the µC preload the counters and then just apply a clock to them. Use the lowest bit to toggle the /READ line of the flash. Built a simple video player that way once while only needing a small µC to control what video loops to play. Will work the same for audio...Greetings,Chris