AMB Laboratories DIY Audio

[RollE2k]

Hello!

I'm building an amplifier where i will use LCDuino and the delta-1 attenuators for volume controller, this is really good for me, since the volume is avalible both remote and at the front panel by using the pot itself.
I have been thinking about buying delta-2 input/output modules also, but for me it all falls on one point - there is no way changing the input from the front panel of the amplifier. At least for me (and i think with many more people) this is a big letdown. There are those times when you cannot find the remote, when you are out of batteries, or maybe some other troubles. Can't be to hard adding the feature for a rotary encoder? I could trade off some other unnecessary features for this one if there is limited memory in the chip itself.. for me functionality goes first!

So my question here is, are you going to add this feature?
And i guess there are more people than me asking for this feature?

[linux-works]

lets use this thread for discussion on front panel extensions (if any, if possible) for the lcduino-1 system.

is this an important feature for you? what things would you want to have controlled via the front panel? what styles do you prefer (buttons, leds, rotaries, pots, touch, lcd, you name it..)

[RollE2k]

Well, myself i would love to have support for a rotary encoder with push button, so i can change the basic settings with it.
Volume is already there, so at least for me its just input change via rotary encoder and possibly the push button i would like. Besides that i think the unit is pretty complete for my needs.

[cobretti]

DEFINITELY push buttons for each input, that's why I didn't buy it. Then up down buttons for programming would be nice. And volume, up down, don't like pot.

[linux-works]

one quick comment about buttons for the inputs, as well as other functions. since the current system uses IR learning, one way to get something going right away would be to buy 2 of the same IR remotes (you can imagine where I'm going with this, lol...)

yes, break one open, steal its pcb and IR emitter and give it its usual 3v from a voltage regulator. mount the small ir board inside your chassis and wire up any button you want and tap into the button matrix pad. should not be hard; you remove the rubber buttonpad resistor mat and then get access to the button contacts. it really should not be hard. then, you can extend the IR either electrically or just plain old optically by 'remoting' the IR sender led to be close to your existing case IR receiver (the lcduino part). still all inside the case. in fact, you can just mount the ir-transmitter led sideway inside the front panel, somewhere near the ir receiver. it will generally be 'open' to signals from inside the case, too

I'm not kidding. this has a few strong advantages: it uses the same tested known code in the existing lcduino, it does not take long for the cpu to 'parse' and there aren't two devices to scan, so the main loop runs faster. its cheap, its not hard to get parts for and you only have to program it once. and you are free to litter up your front panel with as many discrete function buttons as exists on the remote (of course).

it might cost $10 for a spare remote, then you'd pick out buttons and a way to mount to the front. but the parts are not expensive and you'd need no new sourcecode changes at all to make use of this. the lcduino system does not know or care if a 'local' IR emitter sent out a command or a remote one that was several feet away. as long as you don't press both at the same time.

[RollE2k]

For many buttons i guess that idea is the easiest solution, but the best solution as whole - wouldn't that be a rotary encoder? would suite the original pot best, and you can probably show what input you are using with a led if you perfer instead/together with the display?

[linux-works]

in a background project, I'm trying out an idea that will bring a rotary control to the motor pot interface and just plug in. yes, using voltage levels as an interface (which is why i was playing with 8pin dac chips lately).

the problem with rotaries is that most systems are not fast enough to keep up. but if I can get a 2nd small cpu to front-end this, not only will it (hopefully) never miss a fast-turn pulse-train but it will plugin directly and not need any code changes on the main lcduino.

the rotary can replace the pot for volume and wherever the pot is used. but there is still the issue of buttons.

on my sercona box, I have a port expander that supports the front buttons but that needed code to be written and some soldering of new perf boards to be done. I gather that few diyers want to do this and would only want to if there was a ready made green pc board for this.

one problem with buttons and diy is that the mounting can get tricky and if you assume a layout and mount the buttons on the board, this limits the chassis size and style you can use. button grids don't usually find their way on diy's.

I didn't go with a full grid, just a few (4) buttons and 2 rotaries. one for volume and one for input selection. the rotary for input selection would NOT be 'free' from the ir remote hack, of course. THAT would have to be new code written or a new hardware interface.

also worth mentioning is that rotaries mostly suck. the cheap dollar ones really do suck and they bounce a lot. their feel is lousy, they are meant for cheap lightweight plastic knobs and heavy metal knobs cause typical RE's to wobble. its not a pretty picture. then, there are expensive ones that are hundreds of dollars. anyone ready to spend that? didn't think so

the cheap ones are only a dozen or two pulses per rev. that means you have to turn and turn and turn to get anywhere. otoh, 'touch ups' where you only want to make small changes to your vol setting are actually more pleasant on these than a real pot (personal style, though).

mechanics are the hard part. getting GOOD motor pots is hard, getting GOOD rotaries is even harder. mounting a grid of buttons is challenging.

[RollE2k]

By the way - is there any alternative to rotary encoder with the "same" function, that would work better - and possibly cheaper/easier to implent?

[linux-works]

there's an alpha brand rotary that does not use the 'tricky' quadrature encoding that I was referring to. it uses 2 SPST NO switches and closes them when you turn them in their direction. but you still have to be able to track that at the fastest twist you can imagine any user doing. to scan for that in hardware and also for IR receive, that's a bit much. the rotary drops events if you twist too fast and I just don't like that behavior! its worth a whole extra chip, to me, to avoid that.

[RollE2k]

So you essentialy mean that there is no easy solution switching inputs with a rotary encoder or other alternative?
I primary thought about switching inputs with a rotary switch and relays, but then i thought why not use the LCDuino/delta2 and be able to use the display to show what input - but since there was no "hardware" way of changing with a switch, i haven't gone that way. If this issue was adressed i wouldn't even have to think about it - that would be the only alternative. And for me i want a rotary switch for input, rather than buttons since that matches the volume-pot the best.