syscall girl posted:

also put a camera up there just because

Panty Saluter posted:

i never understood felt turntable pads, seems like it would hold static electricity and such

SRQ posted:

#1, which is now complete and boring: Build the ultimate computer as of 1999 for video games. I play quake and old dos games on it occasionally, it's fun to have.
#2, which I just started because I'm an idiot: Build a Win2K server using an old laptop to host a dedicated Quake 2 (or others?) server. For some reason Win2K is hella loving up.
#3, shitpost.

What stupid things do you waste boredom time on? I know Jonny has his BBS and somebody is making a Yosvape. Where the gently caress is the yostop anyway.

enotnert posted:

full fatty tube driven jerky

Panty Saluter posted:

i never understood felt turntable pads, seems like it would hold static electricity and such

N.Z.'s Champion posted:

Trying to implement Google Material's ripple buttons in a different way. It's rooly ugly right now but it's just a proof of concept

Luigi Thirty posted:

is there an SPI programmable sound generator that would be comparable to something like an AY-3-8910 or other simple square wave beep blooper?

Trig Discipline posted:

there's the new AYY-L-MAO, have you tried that one?

Base Emitter posted:

two or three pwm outputs on any mcu is basically equivalent to the 8253 timer chip used for sound in an original ibm pc

that's pretty primitive compared to a SID, but its a start. write some software envelopes/lfos to modulate the whole mess and you're off to the races. if you really want to get fancy use another timer to clock a switched cap filter

dammit now i sort of want to make a synth out of an avr

echinopsis posted:

so im trying to work out what kind of led driver i need for an led but the datasheet only gives me the wattage and the voltage of the led. is that enough info to get forward current from?

echinopsis posted:

also so leds need a certain voltage to turn on. if the voltage is sufficent can you restrict the current to make them dimmer or is it easier to pwm them

Sagebrush posted:

yea it is. power = voltage * current. if the led is 3.6v and 5 watts then it's (5/3.6) amps = 1.38A

white leds are almost always around 3~3.6v so you can estimate the current draw p. easily from the power figure alone

quote:

you can restrict the current to decrease the brightness yeah, but restricting the current means burning some of it up in heat and wasting the energy. leds can be strobed at 1000s of hz no problem so it's a lot more efficient to pwm at maximum intensity than to try and screw with the current

note: if the led says 5 watts, 3.6 volts you are perfectly capable of running it at 1 watt by only allowing 350ma through. as long as the voltage is right the led will light up, just very dimly if there isn't enough current. you can also overdrive leds, put 2a into that 5w led and now you've got a 7.2w emitter but this will seriously kill the lifetime of the chip (even more so if you don't keep it cool). exponentially too, like if driving a chip at 30ma gives you 50,000 hours, then driving it at 45ma might give oyu 1000 hours and at 60ma maybe you get 10 hr before it starts to get dim and lovely looking

Sagebrush posted:

fyi if you go for that cob flat emitter thing you're gonna have to mount it on a big rear end aluminum plate for heat sinking. get some thermal epoxy and glue it down. excess heat is what kills the led, and even a new efficient led at least 60% of the input energy is turning into heat. and all of it is coming right out the back of the semiconductor junction, the worst possible place for it.

fun fact this is part of why it's taken so long to get led headlights in cars. the light output is temperature sensitive and you have to avoid both the situation where the emitters get hot in arizona and only put out half the light they're supposed to, and the opposite where the guy in canada starts his car up in the middle of winter and for the first ten minutes his headlights are twice as bright as is legal

Sagebrush posted:

fyi if you go for that cob flat emitter thing you're gonna have to mount it on a big rear end aluminum plate for heat sinking. get some thermal epoxy and glue it down. excess heat is what kills the led, and even a new efficient led at least 60% of the input energy is turning into heat. and all of it is coming right out the back of the semiconductor junction, the worst possible place for it.

quote:

fun fact this is part of why it's taken so long to get led headlights in cars. the light output is temperature sensitive and you have to avoid both the situation where the emitters get hot in arizona and only put out half the light they're supposed to, and the opposite where the guy in canada starts his car up in the middle of winter and for the first ten minutes his headlights are twice as bright as is legal

Jonny 290 posted:

interesting. does this mean that possibly watercooling LED arrays in, say, grow room setups might become a profitable effort

echinopsis posted:

thermal epoxy... the poo poo you put on your CPU? ive got some of that. or is it more like a glue?

Sagebrush posted:

if you want that kind of sound you're talking about someting a lot more complex than just square waves, so try the yamaha ym2612
https://www.youtube.com/watch?v=DCHuoQAqrUU

i know nothing about programming them but they make pretty music (it was the fm synthesizer in the sega genesis)

the comedy option would be a mos technology SID chip but gat drat those things are hard to find these days
https://www.youtube.com/watch?v=MOhzkWZHBfM

Sagebrush posted:

the comedy option would be a mos technology SID chip but gat drat those things are hard to find these days
https://www.youtube.com/watch?v=MOhzkWZHBfM

echinopsis posted:

del=del+iterate;

if (del>100 OR del<0)
{
del=del*-1;
}

Luigi Thirty posted:

i'm confused by what that loop is trying to do?

echinopsis posted:

oh yeah
what a fuckin moron

Luigi Thirty posted:

sound chip chat: the SN76489 is another option since it comes in a 16-pin DIP package and is very similar. the 8910 is a 40-pin dip since it has two 8-bit parallel I/O ports in addition to the sound hardware for some reason.

Sagebrush posted:

dno't use delays in ur code unless you actually want the chip to pause execution and ignore all i/os for whatever length of the delay. better way is to use a repeating timer.

code:

int d = 30;
long t;

void loop() {

  if (millis() > t + d) {
    //do a thing every d milliseconds, 30 here
    t = millis();
  }

}

you can replace every occurrence of delay() in your code with something like that and it will be 1000% better.

Sagebrush posted:

this is neat stuff and i'd be interested in finding out what you do w/ it. cheap, low-overhead sound is something i'm always looking for on microcontrollers and those chips seem like neat ways of doing it

echinopsis posted:

i know why delay is bad and in other cases i would avoid it but in this case doing what you said seems inefficient coding because ALL this is doing is flashing lights and I have 0 intention of doing anything else with it and its so small and simple anyway if I ever DID want to do more with it it'd be so simple to rewrite. or am I still wrong?

Sagebrush posted:

if literally all it's doing is blinking led then nope go nuts, there's no problem w/ using delay. usually the first thing that gets screwed up is if you want to read a button though. your code is stuck in a delay (or god forbid multiple delays within a loop) and you press the button but it can't read it. maybe u can use an interrupt but it's better to just put it on a timer.

quote:

i wouldn't say it's "inefficient" though. whe you use delay() im pretty sure it just does NOP NOP NOP NOP NOP NOP 16 million times for every 1s of delay. not exactly "efficient" :P

Sagebrush posted:

i understand that a lot of the sids you can get on ebay/aliexpress/w.e are fakes , but what does that mean? do they still make sounds? like i don't care if they model every filter quirk and rc wobble perfectly, and will make the most perfectly -authentic- sound reproduction of your 1982 video shame sound track, as long as they can still make the different waveforms and envelopes well enough to sound like c64 music.

echinopsis posted: