smashtv

Whoa horsey! Average led=20 ma. 20 of these is an extra 400ma load, that's almost half of your available 5v current on the core....run more leds, modules, LCD backlight etc and there will be problems. Don lets get your first box done before we start sending the new guys down the "whoops I let out the magic smoke" path please..... ;) Best Smash

Please define "box" in this context.... depends on how it's coded....I doubt your "box" is able to know 128 channels by looking at only one frame.... That method is too slow, no matter what the pic is capable of...need to grab more than one channel of data on each read. 128 reads of 75fps DMX takes almost 2 seconds. Best Smash

Very cool....The last management-human there told me they were working hard on this....Looks like it's working. :) I can't believe they have done as well as they have considering the growth rate....Google is ramping up to compete with them now, will be interesting to see real competition in that arena. Best Smash

Depends on the manufacturer.....some are x ppr, some are only one pulse when you change direction, and at least one seems to keep the switch closed based on last direction.......That got me too! :) Smash

This is the only way without some crazy coding tricks....DMX runs at roughly 8 times the data rate of MIDI, and every value is transmitted in every frame of data vs. MIDIs only as needed way. The difficulty in coding this is directly related to what you want to do, ie do you need a full frame of DMX data converted to MIDI, or just a few channels of DMX triggering MIDI events. Grabbing a partial frame is easy, you can set your uart in the MCU to the wrong serial format and DMX will cause an error flag at the start of each frame, then you count channels and grab only the data you need. (google for the specifics on this, it's out there) Conversion of a full frame means reading and storing 512 8-bit numbers 75 times a second (or more or less, depending on what rate your fixtures expect-75fps is most common), a task most MCU's are not capable of, not even considering doing something usefull with that data. Of course at that data rate you can skip complete frames and get back some cycles at the expense of response time.....jumping from DMX down to MIDI you could probably only read every 8th frame and not see any real world lag. If you need an off the shelf solution an open DMX usb interface (see Entec's site) can read DMX data in to a PC/mac, and there are MAX objects and other drivers to give you access to that data. An expensive off the shelf solution might the LanBox, it has the capability of reading DMX but I don't know if it can generate MIDI from DMX stand alone (without a PC) Let us know what you find.....Even if you don't get to goal your research on this will help me us give a better answer on this in the future... :) Best Smash

Lemme bring me post over here where it belongs: PS before I forget: Here are some notes about switching audio with an opto: http://www.silonex.com/audiohm/softswitch.html, But we don't need to be as quiet as the ideas shown there.... Just an interesting link for future use in MIOS effect control vactrol stylee.... :) Also another method I don't think you guys have covered....It's a costly one but purist-approved.. ;) Relay attenuator...It can be built to exactly emulate a potentiometer in a circuit, perfect for anything that passes audio signal through a pot..... A basic explanation is here: http://jos.vaneijndhoven.net/switchr/index.html, and you will find a lot more on the subject by googling "relay attenuator". This type of rig can easily emulate any pot taper you want.....But again is only for people who have a spare case of relays sitting around or who need a setup that has better sonic characteristics than a real pot and a fat wallet.... :) Is an opamp buffer stage on the digipot (to get rid of zipper/preserve sonic integrity) out of the question for what you guys are doing? Sorry I have not been keeping up in class. ;) If I ever have any tinker time again I'll be testing some PGAs for audio quality and useability, I have an unrelated project that could really be simplified with these....If I can slow down enough to code an app for them...... :-\ Wow shifted gears 3 times in one post, without pushing in the clutch! ;D Best Smash

wow don't rely on the PayPal insurance thing, if you read the fine print on that there are a million hoops to jump through for it.....and if you do succeed in doing that dance you only have about a month to get the transaction reversed.....and to do that you must get PayPal on the phone, which is a nightmare..... Don't get me wrong I love PayPal, they have opened up international commerce to everyone, but doing that makes them very busy, and hard to get on the phone. :) Can you imagine running a bank with 80 million plus accounts? I get 30 orders and I'm behind! :) Read the fine print and be aware. ;) Best Smash

That one looks like what you need... A similar part should be available from just about any company that makes optoisolators, just in case these specific ones are hard to get your hands on or are priced like gold.... ;) Hopefully I'll get enough pending orders knocked off the list this weekend to get yours shipped fairly quick.... Best Smash

Yes. I am partial to the 6n138, but that's only because I have many tubes of them, and they are closer in spec to the current requirement of a normal LED than most optos. :) I would say knock up a tester proto for this part of the circuit before anything else, that way we can be sure there are not gotyas like fluttering vcas etc. Take a look at http://www.jaycar.com.au/images_uploaded/optocoup.pdf for all the hints about dual darlington optos.... ;) Upon a closer look, the 138 might not be the right tool for the job, unless you have are planning for an inverter in there somewhere (would have to have the MIDIbox open the mutes to use the console, needs to be only muting when the MIDIbox is telling it to be quiet....the 638's are more suited to switching power than a ground rail due to that dual darlington design)....So what is needed is a simpler device, with an efficient diode (20ma current draw or less for the LED) and a receiver side that is not so uppity and would be happy to switch a ground without involving the positive rail.......unfortunately I don't have a number to go with that spec, so it's your turn to do some digging and let me know if you find some candidates. :) Best Smash PS before I forget: Here are some notes about switching audio with an opto: http://www.silonex.com/audiohm/softswitch.html, But we don't need to be as quiet as the ideas shown there.... Just an interesting link for future use in MIOS effect control vactrol stylee.... :)

The best way to understand these: When you turn it clockwise, it closes one switch, turn it counter clockwise and it closes another. Depending on manufacturer/model it will either do x closures per rotation, or only one closure when the direction changes. This one from Mouser, made by alpha/xicon only closes the respective contacts when the direction changes according to the datasheet. These don't seem to behave like encoders, and require the same amount of available pins.....I guess I'm not seeing the gain here vs. a real encoder (these cost 5x the price of an encoder). Best Smash

Hahahaha me too! ;D Now I can proudly proclaim that I used my "hot desire pistol" to pack orders..... ;) This method is called HASL (Hot Air Solder Leveling) by the pros, and is a long time practice as the least expensive tin method.... The problem is it gives you a solder contact surface (mostly lead if non RoHS, mostly some more harmful alloy if RoHS compliant) and neither works well as a contact surface conductor..... :-\ So while it does stop corrosion effectively, you might find yourself still really having to mash the buttons (depends on the carbon mixture used on the button pad itself) and some fluxes like to eat plastics (a whole other issue)..... :-\ I have used a product named "tinnit" (google "tinnit pcb") a few times, it works well if you carefully follow the instructions, and don't allow any other chemicals near it (in other words a tiny amount of anything else in the solution ruins it, like any soap film or tap water left on the pcb). The wildcard on this is that I don't know if you can get a thick enough tin deposit on there for reliable operation without it rubbing through to the copper. Best Smash

The simple answer is no....It would require some coding to an SMF that none of us has time for.... :-\ Personally I think after-the-fact post editing should not be an option anyway, as it opens a whole can of worms for people to play revisionist history, and lets people post something that's not completely thought out. A perfect example is an exchange I had with a user who proceeded to school me on something he really knew nothing about (brought some agression/baggage with him to the forum that day).....I saw his post minutes after he made it, and spent 15 minutes or so on a correct reply to that post as written. By the time I posted, he had edited his post to remove everything he was clueless about, including the unwarranted aggression....So what was left was the appearance that I was flaming a newbie without provocation. I understand some people need to correct a typing error or a mis-typed sentence, but that's what the preview button is for. Editing a -concept- after the fact just proves you were not ready to post about it in the first place. This rant brought to you by not enough coffee yet, and I'm not aiming at anyone specifically, it's just my honest opinion. ;) Best Smash

Ok I'll repeat myself here vs. watching you guys throw your time and money away to learn a lesson.... Without tinning the contact surface, the bare copper will self-oxidize and you will find yourself taking this apart every few months to clean those contact points. Less time if you live near salt water. Start praying now that it does not fail you during a show. :-\ The easy way? Cut up the board that already has the correct contact surfaces on it, use them instead.....epoxy to a carrier protoboard, etc. Best Smash

More info please. ;) Be sure to pull the PIC and optocoupler until your voltage tests good...don't put them at risk during power supply related testing. Tell us how it's wired to the power supply, specific test point voltages, etc.....Details help get specific answers. :) Best Smash

oof I hate to hear that....even after so many years of desoldering, there are still some that give me problems, even with the right tools.... I -think- you have seen my Core page already and my resistor ID page is here: http://www.avishowtech.com/mbhp/res.html I'm thinking you are probably way past that info, so let's talk desoldering.... The bulb type desoldering tools are not that great for double sided boards with plated through holes, and only the really high price solder suckers do anything but frustrate. The workable alternative is "Desoldering Braid", from your local radio shack. Look for this: http://www.radioshack.com/product/index.jsp?productId=2062744 The secret to this stuff is all in the technique, and you will want to practice a few times on a throw away board. Lay the braid as flat as possible on the solder that you want to remove, put your iron on top of the braid, and count to 5 or so then remove the iron (otherwise the pads/traces will try to lift off the board due to overheating). The idea is to get as much of the braid's surface in contact with the solder, and as much of the beveled tip of your iron in contact with the braid....a little practice will show you what I mean. This stuff works like an oil lamp wick, and for it to do it's thing you want just the braid touching your target solder, not the iron as much as possible. In all the years wrenching games out in on location there were always at least two rolls of this stuff in my toolkit....and an extra set of forceps just to hold the braid since it gets very hot as you go. I tried every brand I could find and quickly realized that the radio shack brand for this stuff is as good as it gets. Let us know how it goes, if the braid gives you problems I'll try to do better at explaining it (maybe with a 15 second video clip) Best Smash

Very cool. ;D hehe no such thing as a daft question, especially when you are talking about bypass voodoo. There are daft answers though, and I'll do my best not to give you any..... ;) correct This all depends on if you will be using the console logic supply or an separate supply....If your console supply is beefy enough to run the MIDIbox also, you will want to lose almost everything in the Core power section, and put that big cap across +5 and gnd as close to where the power comes in to the Core as possible. In other words, if this were my build I would lose J1, BR1, C5, C6, and IC3, Then I would bring in the 5v logic+gnd from the console on J2, and wire the big cap directly to the pads for J2.Looking at the notes from the last broadcast meter bridge I built many years ago, on a clean linear supply one 10,000mfd @ 15v across the power rails, and the usual .01mfd caps everywhere were enough to keep the 500+ LED contraption from noising up the ground rail....the big cap is kind of an indirect way of lowering the noise floor, since a lot of self generated digital noise on the power rails it due to fast changes in current requirements vs. trace/path impedance. This is minimized by the cap helping the power supply meet demand from the circuit at the point of load. The car stereo guys use the same technique these days, calling it a "stiffening" cap. ;) The usual .01 mfd should do fine, I would build it first, listen & test, then add these only if there is a noise issue. If you do end up going with a separate supply, you might consider losing the ULN drivers, and driving optoisolators in place of the usual DOUT/LED configuration....This would keep everything isolated like the relay method, but without the relay coil noise. :) So I can get a little more specific.....what is the make/model of the console? I'm hoping we can dig up a schematic and get a more accurate idea of what's a good idea and what is a bad one... ;) Best Smash

Bahh you are confusing humiliation with learning something.... ;D None of the heavies here expect you to come to the table with all the knowledge you need, but we do like to see people ready to learn.....any humiliation is only in your viewpoint.... ;)Everyone starts somewhere, and anyone who has not spent hours chasing a failure due to wiring is either lying or still a newb. ;D In my defense there would be a SI designation there, but there is no room on the board for it! Always follow the schematics, all other info including the board layouts come from those files. That trace is on the topside. Doc has it right, SI must be connected. Jinx! (you posted while I was writing!) Are you sure you are not wired up to a menu button that does not send a MIDI message when you press it? Best Smash

Just to be sure: do you have all the 7805 tabs/heatsinks isolated from each other and from ground? (sorry, I have slept/forgot since we talked about this last) ;) Remember, you must feed regulators with at least 2 volts more than the rated output voltage for them to work right....anything from 7 to 30 volts is acceptable for 5v regs but the magic number seems to be 9vac. (more or less than 9 gets things a bit hot depending on load) -Most- of the time this will give you 12vac @ 2.5A...are you doing a phase trick?...Check out http://sound.westhost.com/xfmr2.htm for some info on transformers. (anyone have a better link?) Best Smash

Heya Doodah! Just to be sure: when you say that shorting the ground activates the mute, In your console is this setting a VCA state, or is it simply shorting signal to ground in a convenient area of the circuit? If it's muting by shorting signal and ground I suggest relays to keep the MIDI stuff completely isolated from the console, since muting through a DOUT/ULN combo without relays will at least tie the ground rails of the MIDIbox and console together, and at worst add a diode and some other not freindly parts to your ground path. If it's a VCA mute then no problems, ditch the relays, but be sure to add some very large caps as bypass on your +5/Ground lines, like 10,000mF at 35v (or more on the voltage). And I would also add a bypass cap to every connector on the MIDIbox side (to keep the shared ground cleaner). If you do have to go with the relays you should consider "low signal" or even RF type relays, or you might see some contact issues as signal loss after a few years use. I strongly suggest shopping the surplus houses for your relays, unless you are wealthy. ;) Best Smash

Yes, that -was- an error (corrected now).....hehe "slight typo", did'nt know there was such a thing.... ;) Sorry for the basic question here: are you getting good 5v and ground when tested at the 4051 sockets? Best Smash

It's cool and all but insane not to load an RGB led as the source. For that much work it should change color like a mood ring when done. ;)

J7-J10, Vs=ground, Vd=5vdc. The unmarked through holes are vias that pass ground from one side of the board to the other. Again it's best to wire all pots +5 together, and all grounds together, then run one ground and one +5 back to J7. J8-J10 are only for convenience on non-standard builds....(for per-group isolation, which will add jitter if used on a standard build) Be sure to take a look at http://www.ucapps.de/mbhp/mbhp_ainx4_64pots.pdf, it shows everything ya need to know. ;) Best Smash

It's already there....Notice the red jumpers on the core on the photo in my LCD page (J5a+J5b).... http://www.avishowtech.com/mbhp/20x2.html Don't jumper all connections though, as this will short 5v to ground, and let the magic smoke out of your power supply. ;) On the grounding question, your pot ground(s) need to tie to any of the many ground points I added to the AIN board. The best (read: lowest jitter) way is to run one ground wire from pot to pot for all pots, then tie that wire to ground.....This will eliminate ground loops that raise the noise floor of the circuit. Best Smash

Hi Robokid I'm really sorry about this, I get thousands of emails a day, mostly spam (I have had these email addresses/domains for way too long now) so I know that messages are getting lost. In the past that was not a huge issue (since I -was- able to ship quickly) now that I'm perpetually behind it's a big issue. :-[ I have an order status page here: http://www.avishowtech.com/mbhp/status.html in case you have not seen it, and please send me a private message here so that I can connect your real name (from my order list) to you as Robokid, and I'll give you a full status report and answer any questions. Best Regards SmashTV

Whoop just to be clear I only changed Moebius' to 452, all other smitin' was the other kids. :) hehe you know what they say about gateway tags, first it's a harmless little scroller then next thing you know your running a colocated server full of pages upon pages of dancing hamster and 3D rendered dancing baby videos......... ;D