11/21/2005

MAS863 | Fall 2005

Assignment:

Output Devices!  Make a game using an output device.

Project:

• 4 different output devices introduced this week:

  • Video - Generate NTSC format to display on a TV

  • Sound - Pulse Wave Modulation through an ATtiny13 to drive a speaker

  • Stepper Motor motion - driven using the mighty ATtiny13

  • LCD - sending messages to the Hitachi HD44780U

• I chose to explore Sound

Tasks:

1.     My initial thoughts were to explore sound transmission over the I0 boards which would enable some progress on my final project.  After having built 2xI0_6 boards as a start to this endeavor (with Grace too), Professor Gershenfeld refocused my attention on keeping the assignment straightforward and concentrating on "output" devices.  The I0 effort will help with the next few weeks as we explore communication and further refine final project panic.

2.  So I built 2x Hello5 boards using the Modella which was fairly straightforward.  Link to the Hello5 files:  software
 

3.Using Hello5.wave.asm from the software site ( wavetable synthesis ), I managed to assemble with AVRStudio 4 and program the boards with the code creating a Sound Wave Generator using the Pulse Wave Modulation technique.  Here are some of the attempted "notes" that I tried.

notes:
;.db18,5,250,5,250,5,250,5,250,5,250,5,250,10,250,10,250,10,250,20,250,20,250,20,250,15,250,30,200,40,100,35,100,35,100,25,200
;.db 18,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250,5,250
;.db 18,5,2500,5,2500,5,2500,5,25,5,25,5,25,5,25,5,25,5,25,5,250,5,250,5,250,50,250,50,250,5,250,5,250,5,250,5,250
;.db18,5,250,10,250,15,250,20,250,25,250,30,250,35,250,40,250,45,250,40,250,35,250,30,250,25,250,20,250,15,250,10,250,5,250,5,250
;.db18,5,250,3,250,5,250,30,250,30,250,5,250,10,250,25,250,12,250,15,250,15,250,13,250,15,250,18,250,18,250,20,250,25,250,25,250
;.db18,5,250,5,250,5,250,20,250,20,250,5,250,5,250,10,250,10,250,15,250,15,250,12,250,12,250,14,250,14,250,14,250,18,250,18,250
.db18,5,250,5,250,5,250,5,250,5,250,20,250,20,250,20,250,5,250,5,250,10,250,10,250,15,250,15,250,12,250,12,250,12,250,12,250
 

4.  The game:  "NAME THAT TUNE!!"  However with only two boards programmed and notes that together only managed to sound like noise, the game would need a lot of additional programming time to fine "tune" the notes to become a true song.

5.  Some challenges I encountered were mainly frying some of the devices with either inadvertent touching of the speaker lead during reprogramming (not a good thing - took out the MOSFET this way) or sloppy movement of the speaker leads when playing (burned out a speaker).  These problems can be mitigated by isolating the speaker leads with some distance and giving them larger pads to make to contact.