lylehaze

Your problem is almost certainly power. The bigger display draws more than the smaller one, and the missing caps at the PIC only make the problem worse. Get the caps in close to the pic, and add an extra one where the display power leaves the board. If that doesn't solve it, try a bigger power supply. You could even TEST this idea by using +5 volts from a computer hard drive connector as a test power supply. (NOT a USB port, those may be current limited) Good Luck, LyleHaze

Hi Freddy, First, I must apologize for the slow reply. After a long period of unemployment, I'm now working, and I managed to put in 66 hours this week, so I have not had much time for web surfing. Back to the point: You are asking exactly the right questions, but I'm not sure what the best answers are. I'll go into as much detail as I can at this late hour: In the existing, non-EQ mixers, ALL of the various controls are "sorted down" in software into simple level controls. This "feature" confuses people who are accustomed to "regular" mixers. A non-Effects example: What I'm saying is that even though the user has all of Volume, Expression, Balance, Pan, and Master Volume.. In reality these all reduce down to TWO volume controls.. One for the right, and one for the left. That's all there is! And they mix right onto the "final" left and right output busses, with NO "master" faders there. Interestingly, whether it's a Mono or Stereo "feed" into the channel makes no difference, it's still two "real" faders. So the EQ.. take the incoming line level audio feed into four parallel bandpass filters.. the result is four separate audio signals, Bass , lo-mid, hi-mid, and high. Now we feed each of those into one of four PGA channels, this is where we get "control" of the EQ.. after those, they all re-combine into a single audio signal that has been tone-conditioned. Now comes the choices.. we can either.. take that "toned" signal into the existing PGA design, and use 2 more channels of PGA for volume control.. OR.. we can make TWO of those 4 band EQs, and have each one dumping directly to the output busses (left and right) Option 1 requires a total of SIX pga channels(there are 4 per chip) for a stereo feed (non-effects) and the audio passes through two gain stages before reaching the output.. OR Option 2 requires a total of EIGHT pga channels, but the signal is only processed through ONE gain stage. Either way could work.. I have not built either yet. I intend to make an EQ after I'm done with the meter bridge transmitter, but I have not made it yet. I DO NOT want anyone to wait for me.. I am busy, and the software is "open" in hopes that others will contribute things like EQ and stuff.. SO this is just my concept of how it might work.. Others are invited to contribute in any way they wish.. (more on that later) Other thoughts: The software is all ASM right now, and I'm not porting it over to C anytime soon. You are absolutely right that it can be modified to do this on a single core, 16 channels wide, no matter how many PGA chips it takes. I would STRONGLY advise that your control surface be done separately, on a separate core. The code is really simple, and it's divided clearly into sections that make sense.. If anyone wants to get in there and make changes, I WILL offer my support by E-mail or in these forums as they go. No Fear! Other details: Smash and I have been detailing how these boards will be produced. The designs shown now in the WIKI are not the same as the final product. I worked hard to make them too small, and also too difficult to assemble. I also made them assuming that everyone would be building pretty much the same thing. Even though they have not yet been released, it has become obvious that these mixers will be used in a LOT of different ways, and we need to make them more diverse and flexible. The new boards will be bigger, but they can still be stuffed in a 1U rack case if desired. The "stack pins" are gone, replaced with more "user friendly" connection methods. There will still be a resistor "breakout area" that will let users mix down to 2 or 4 audio busses, but it will also be easier to break ALL the outputs separately, in case you want to do something weird. It looks like we'll be putting 4 PGA chips on each board, so larger projects can be realized with fewer circuit boards. Also, it looks like the "input processing" section may be reduced or eliminated. There are just too many different things people want there, from simple op-amps to digital preamp controls.. and a fair number of people need no input processing at all! So you'll have the option of "designing" the EQ yourself, just by making 4 bandpass filters, and then hacking the software into doing it your way, whichever way you choose. Honestly, it tickles me to no end that my project is coming around, and it will probably lead a lot of experimenters into playing with analog circuits. We may even need an "op-amp" questions area on the forums! (OK, probably not) I didn't answer your question, but I hope I gave you what you need to begin thinking about it. Further discussion is welcomed, even if it takes me a few days to answer. LyleHaze

OOooh, Pretty! Sincere, but short. Keep up the great work! LyleHaze

OK, so I am NOT a Mac expert, and I don't even play one on TV. But you give a few good clues.. So we know the processor is running and the display and wiring are good. Power supply also working OK. So we know that Mac MIDI OUT to MIOS MIDI IN is working, and we know that MIOS is in control of the core. So it appears that MIOS MIDI OUT to Mac MIDI IN is not working, a guess based on the clues you have given. Since MIOS MIDI OUT used to work, I doubt it's a wiring problem. Since your MAC setup has changed, that is the first place to look. I would suggest a MIDI LOOPBACK test on your Mac.. You already know it can send data, so connect MAC MIDI OUT to MAC MIDI IN and send data to yourself. Then work on receiving it back into the Mac.. that should reduce your trouble area to the most likely issue. Once you have the loopback working, you can re-connect the core and get the mac and core talking in both directions. The above advice is NOT mac specific.. someone who knows macs can offer better advice for sure, but it's a start. Good Luck, LyleHaze

I get a few hours of sleep, and this shows up in my mailbox: http://www.midibox.org/forum/index.php/topic,14153.msg122273.html#new Which leads to a project on doing exactly what we were talking about in picbasic! Sometimes it just comes together. :) Thanks nati! LyleHaze

The good news: I have semi-working code in straight MChip asm for a 18F458. The Bad news: I just moved a few weeks ago, and I CANNOT FIND A DAMN THING. I have not yet unpacked my office/shop/workbench/picstuff. I'm currently working 7 days a week, usually 12 hours a day. If you can wait a few weeks, I should have a non-MIOS remote receiver that supports channel select and volume/balance, probably from a (or ANY) sony remote, and send out MIDI messages as a result. From there, it should be easy to edit it up to whatever details you want. The 458 code is real close to compatible with 452, so no problems there. I will TRY to get it in a few weeks, but with work going off-the-hook, it's hard to make promises. Nice to see you Pilo. :) Lyle

Helping hands: I have one, and I use it for connectors on wire leads. I grab the connector in the clip, and hold the wire(s) with my left hand while I hold the iron in my right. Tin the wire and connector with solder in advance. Easy connections. Board Vise: I use it a LOT when building up a PCB, but only if it can hold the board by the edges.(The jaws have V-grooves for that) Once the board is in, I am usually grabbing for the big locking handle at the bottom, to flip the board up or over, re-position it for stuffing or soldering or a visual inspection. Especially with skinny boards like the mixer V2, it just makes life easier to keep it in the vise most of the time. I find that holding the board vertical gets a lot of use, I can stuff and solder easily without anything falling out. It's all about personal preferences. We all have different habits and tricks we have learned along the way.. I'll never forget the first time I saw someone remove all the chips from a board using just a propane torch. Heat the entire backside of the board at once, then slam it into the edge of the table and watch the chips fly off.. I thought he was crazy, but it did work!

It's funny that you said it that way... I'll agree that you shouldn't have to spend hundreds on tools so that you can build a $30 core.. But I will confess, I am a soldering iron snob. Having used a temp controlled iron, I could never go back, and I do believe that temperature control is all but required for PCB work, to avoid overheating components or traces. I need to qualify that: You CAN do damage with a temp controlled iron, it's just that you have to be a little more deliberate to do it. It's very easy to do accidental damage with a non-temp iron, since it's temperature will vary based on a lot of different details. I also think a temp controlled iron will give new techies a much better chance at being successful, and that is important too. But it's all just my opinion. I COULD build a Sammich with a cheaper iron, but I've been soldering for longer than many people here have been alive :) Buy a cheap meter, get cheap needlenose and cutters if you're on a budget. But if you can afford an iron that has a thermostat, even if it's not adjustable, get it.. because bad soldering will only piss you off, and that's no way to enjoy your Sammich. This is ALL just my opinion. If you don't like it, ignore it. :-) LyleHaze

http://www.midibox.org/forum/index.php/topic,14031.0.html We discuss "what" more than "where", probably because we are from all different countries. Here's some tool kits, but I don't like the irons they use: http://curiousinventor.com/store/category/40 but if you're not in the states, it's probably easier to find these things in your own area. Have Fun, LyleHaze

Welcome aboard! A good place to start might be to read the post just above yours, titled There you will find a detailed description of what kinds of posts should be posted under the "Midibox User Projects" Forums. After looking around a bit more, you might find a more receptive audience under "Midification", or perhaps "Design Concepts". Once it's built, we'll all help you work out the bugs in "Testing/Troubleshooting", and if it comes out really pretty, you can even post pictures in "Midibox of the Week", where it will surely get lots of praise from everyone. It's all just an effort to keep things somewhat organized. Again, welcome aboard! LyleHaze

I didn't "hold back" as a tease, it's just that I have not written that particular app, so I was leaving the comment space to someone who has. Lately I have been more hardware anyway, so I wanted to cover that detail. Many folks don't know about "inrush current", and they build a driver for a light bulb that is just enough to handle the normal current for the bulb.. then they get disappointed when it goes "poof". Clem added great details: Most Midibox applications use a DOUT board for digital (on/off) outputs. a DOUT output can drive electronics, or an LED, without any additional help. There are chips we use with DOUTS to get a stronger signal for LED matrixes (ULNxxx?) If you want to drive something much bigger, look into either a relay, or a "solid state relay" that has an LED as it's input. At that point you could be switching entire strings of Christmas lights (by MIDI!) or your coffeepot, or the motorized electric shades you put on your windows. What I do NOT have personal experience with is exactly how to set MIOS up to drive your DOUT from a note ON/note OFF message. I know it's possible, and I'll bet it's not difficult, but I will let someone with more detailed experience answer that for you. A DOUT board supports 32 outputs, so you'll have lots of room to expand your ideas. Take a look in the WIKI and the uCapps site. Look over the schematics for a core and a DOUT board, and decide whether you want to build them from scratch or buy kits. Look over some existing projects, maybe the MIDIO128 would be a good start.(I'm guessing) Then figure out what you can do with 32 LEDs that are individually driven by MIDI. Part of the "fun" is learning a bit of electronics and a bit of programming to realize your project. No Fear! It's all about making dreams come true. Have Fun, LyleHaze

regular lightbulbs have a "inrush current" when turned on that is many times the normal current load. Consider LEDs instead of lightbulbs to avoid this problem. I'll leave the MBox details to someone who has more experience. Have Fun, LyleHaze

regarding encoders or pots for a "mixer" type application: This depends largely on the number of possible control sources. If you will be controlling from one and only one control point, then pots are great as they can remember where they were physically. But if you may be controlling from more than one point: Control Surface, recorded presets, sequencer, remote of some sort, then encoders may be the preferred option. Have Fun, LyleHaze

Excellent for you! Just a few words of unsolicited advice: Some 7805's require up to 7.5 volts to work, so in the interest of margin, you should probably not add any more resistors. Any 78xx regulator that has the center pin at REAL ground also has it's tab there, so using the case for a heatsink is fair play. :-) 79xx regulators and stacking one regulator above another prohibit this. You might try a shorter ribbon to the display, if possible. Have Fun, LyleHaze

I was able to make a "back up" from the original PC to a stack of DVD discs, then restore those to the same PC after a windows re-install. This might work to a new PC as well. Apple is just trying to protect the musicians from free copying of their music. LyleHaze

As long as it works, :) Thanks, LyleHaze

OK, so I have no time to read the code, and I'm feeling more like a hardware guy this week anyway. But the above statement has a problem.. A "common anode" LED matrix requires some sort of driver to supply +5 volts to each row(or column, if you turn it sideways) This will be more current than a PIC pin (or DOUT pin) can usually handle. so far, so good. In the case (rough example) of an 8X8 RGB matrix, up to 24 LEDs in each row(column) may be lit at once, requiring maybe 20 ma X 24 = 480 ma (1/2 amp). So you'll certainly need a driver there. My problem.. you said "BC547", which seems to be a NPN transistor. Since it is supplying the + side, I would expect a PNP transistor there, unless you're playing some weird biasing tricks. Normally, (a truly dangerous word around here) NPN transistors provide a switch on the LOW side of the circuit, and a PNP is a "high side" switch. Or simplified, NPN is negative, and PNP is positive. So either you quoted the wrong number, or I'm confused, or we just found the problem in hardware! Hey, I could be all wrong here.. but it might be worth checking out. Have Fun, LyleHaze

The DIN and DOUT modules are connected serially to the PIC.. Scanning these takes time, and processing the results takes time as well. It sounds like you're ready to leave MIOS and go straight into ASM code. Choose a chip (maybe PIC, maybe something else) with enough pins so that you can directly access every row and column without using DIN and DOUT shift registers. The clock speed of the chip will set your capability. If the only task is scanning your keyboard and sending MIDI, you will have a great introduction to assembly language programming. If the quality of your output depends on how fast you can scan the matrix, then get off the shift registers and write your own code. Well, that's one opinion, anyway. :-) Have Fun, LyleHaze

My personal life has been very busy, including moving twice in the past six weeks. I am working ten hour days now, so I won't be online as much, BUT, Smash and I were working a bit just last week on ways to make the project better. It is still very much "alive", we have not forgotten it yet. We just want to get it as good as we can for the very first version, so everyone can be happy the first time around. :-) It's not ready yet, but we are still getting closer. LyleHaze

The serial output from the PIC, (used for MIDI OUT), can both source and sink current, so you would get SOMETHING if the polarity is reversed. Good Luck, LyleHaze

Changing the crystal from 10MHZ to 20 MHZ will either fix it, or make it fail twice as fast. :-) Glad you found it! 8) LyleHaze

It sounds like you know this already, but I'll mention it for the sake of other readers.. The ideal is "temperature control", not "wattage control".. having a thermostat makes all the difference in consistent soldering. I have an OLD Weller WTCPN iron. It is NOT adjustable, but it IS temperature controlled. I wouldn't trade it for anything. In these, the tip sets the temperature. You can hear them "clicking" as they regulate the heat. The modern equivalent is something like:WTCPT You can upgrade if you want to for variable temperature, but do NOT downgrade to "wattage control" in the consumer models.. Just my two cents.

Welcome to the MIDIBox forums. Glad you got it sorted. Eagle is really friendly, only AFTER you learn all it's secrets. :-) There are some here who like other free programs. It would help a bit if you choose the forum group more carefully.. For a question about Eagle, I might have chosen "Tips and Tricks" or maybe "Miscellaneous".. It's not big deal, just an effort to keep things a bit sorted. Welcome aboard, and have fun!! LyleHaze

Dubstructor, There are a few things in that drawing that trouble me a bit.. BUT my experience with discrete transistor circuits is not great, so instead of exposing my ignorance on the subject, I'll just say that I'd want to test it thoroughly before deciding to keep it. I think TKs "no parts" solution is looking better all the time. If you want to discuss what I _think_ might be a problem in this circuit, PM me and we can exchange artwork by E-Mail. Have Fun, LyleHaze

I have said it before, and I'll say it again: That "T.K." guy is pretty smart. :) Have Fun, LyleHaze