lylehaze

Hi and Welcome, Re: Pic choices the 18F452 has been the "standard" since we upgraded from the 16F family. It is the assumed "normal choice" for what you are describing. The 18F4620 has more RAM and is useful for MBSEQ applications that are memory hungry. AFAIK that's the only project so far that has been "expanded" into the bigger memory map. The 18F4685 includes a CAN peripheral (Controller Area Network) which is currently being considered as a fast network for connecting a bunch of MIDIBox based projects together. (MBNet?) I'm pretty sure that all are pin-compatible, so be sure to use a socket for your PIC chip. Beyond that, I'd say the 452 is the best documented option, and should cover your needs nicely. Choosing a header number? Try clicking on the "javascript header calculator", or just go with Zero. That's usually the best choice for a first PIC anyway. Have Fun, LyleHaze

I think the problem would be if you switched while either one of the signals was in the middle of a message. That would corrupt the message and possibly confuse the UART. It would also require more parts, as there is no way I know of to switch the UART inputs in software. _But_, don't let me discourage you. If you are sure that's what you want to do, Enjoy the challenge! LyleHaze

The PIC18F452 has one UART, so it will only support one MIDI IN unless you have a little help. There is a "IIC" or "I2C" MIDI module that can add another input, or there is a MBNet offering (very recently) that will allow you to network modules together over a CAN bus. This would require a processor change. I'm no expert, but I think those are your options at this time. I'm sure if I got something wrong, then smarter people will correct me. Have Fun, LyleHaze

If you have a metal case, you might try something like this: http://www.midibox.org/dokuwiki/lib/exe/detail.php?id=midiboxmixerhardware&cache=cache&media=psandcore.jpg Don't look at the core regulator, look at the two on the power supply in the middle of the picture. I'll probably change the one on the core over too, eventually. The tab of the 7805 is at "ground" potential, so just mount it off the bottom of the board, and you can use your case as a heatsink. Note that I sanded the paint off there, I used a dab of thermal paste, and I did NOT do this with the negative regulator, as its tab is not at ground level. Have Fun, LyleHaze

Glad you got it working.. Interesting note on the Uno: Some are "class compliant" and some are not. Earlier ones needed a driver installed, later ones are "Class Compliant" and use the builtin driver in XP and OSX. I bought one when I was writing a class driver, and got one of the last ones that will not work. Oh Well. LyleHaze

Is the 7805 getting hot? Careful, it might be hot enough to brand your finger. Good Luck, LyleHaze

For the 7805 on the core to work properly, it needs a supply that never falls below about 7 or 7.5 volts (depending on brand). The rectifier can take AC or DC in, but it will drop about 2 volts as well (diode forward voltage drop). If you take out the rectifier and regulator, it MAY work, but now you are depending on the quality of regulation of your "mystery power supply". If it has problems, they might very well NOT show up on a meter. A meter is not fast enough to show spikes and transients. I'd suggest sticking with the rectifier and regulator that came with your core, and using a supply of about 9 Volts ac or DC to drive it. It's the most reliable choice you have. Good Luck, LyleHaze [EDIT] You might want to read "Core Supply theory of Operation", near the beginning of this forum list. It can answer some of your questions.

@TheProf I thought I took "Outside the Box" literally instead of laterally. I mean, that _IS_ Where you put the little feet. :D I'm glad the weekend is here! LyleHaze

I've got two answers for you.. First, I agree with the Prof.. Time goes left to right, and pitch goes high to low. It's only natural. I think of pitch as going UP or DOWN.. seeing it represented that way makes it the most recognizable. And when someone wants to know how much TIME a sequence takes, they always ask how "Long" it is, they have never asked me how "Tall" it is. ;-) BUT.. I like to think "Outside the Box".. so perhaps the best answer is to run down to the store and get TWO sets of little rubber feet. Now the option is "User-Adjustable"! Have Fun, LyleHaze

I have not yet "been inside" the MB64 code, so please take this with caution. There is code in the MBMixer that will convert a 7 bit linear value into an 8 bit Log value, and also code to convert 8 bit Log curve back to _AN APPROXIMATION_ of a linear curve. The resolution is a bit grainy, especially at the low end of travel. It is sized only for 8 bit to 8 bit conversions, if you need something different you'd have to remake the look-up-table. To find it, get the archive here: http://www.midibox.org/dokuwiki/lib/exe/fetch.php?id=midiboxmixersoftware&cache=cache&media=mbmixerv1.zip (If that link doesn't work, it's in the WIKI at the end of the software page for the MBMixer) from the zip file get "logbyte.inc" and look inside for a function called "AntiLog" and it's data table, alogtable. Having said all that, it's not the "right" way to go. Your MB64 will be different from everyone elses, and if it doesn't work "just right", you'll be on your own. I agree that using the right parts is the best way to go. Good Luck, LyleHaze

http://www.edrum.info/index.html Have Fun, LyleHaze

Wow. It sounds like the plan is changing. Your first post asked if you could map program change messages into different patterns of relay outputs. Your most recent post has added Analog Inputs, Analog Outputs, Digital inputs for some buttons, and some LED outputs as well. It's probably a good idea to get started with a simple project, and learn how MIOS works. You can add more stuff later if you want to. The best part about MIOS is that you can do your own programming, and make it work exactly the way you want it to. You can learn a lot by looking at the source code of other projects here. I would suggest that you start with a simple project, like the one you mentioned in your first posting. "MIDI IN to maybe 16 or more relay output". Build a core, display, and a DOUT module. Hook up LED's to each DOUT output, so you can see what you are doing. Try writing a simple program to turn on LED 1 when you get a Program Change #1, LED #2 for Program Change #2, etc. Then change the program to set ALL the LED's with each program change, like you described in your first post. Finally, when you have all that working, we will talk about how to control relays instead of LEDs. Once you have made it that far, you'll have a very good idea of what it will take to get all the AOUTs and AINS and DINS to work too. And you'll have a one-of-a-kind project that you designed and programmed yourself. I think you'll find there are a lot of people here who will help you along the way, but probably not too many that will write it all for you. If you want to make this work, you're going to have to learn how to do some programming. TK has offered us all a great starting point, with MIOS already doing the hardest parts. And with the kits available, you can get the hardware started pretty easy too. All that's left is for you to learn to do a bit of programming, so you can make it work exactly that way you want it to. That's just my suggestion. Have Fun, LyleHaze

Now that just figures.. I went through some VERY ugly home-hacking drill-press-abusing bloody-knuckle antics trying to get the MBMixer case to look kinda nice enough to show. Now somebody suggests waterjet. Why didn't I think if that? I have two of them at work, and I'm the programmer! To be fair, these are the pure-water type, the ones that are used for metal usually have an abrasive in the water. But if I went slow enough, it would probably work. Maybe I'll take a scrap of Aluminum to work and try it. LyleHaze

This depends on the type of backlight. If it is LEDs, you can calculate the correct resistance using one of the LED resistor calculators on the web. Make sure you figure using the highest voltage that you ever expect to handle (fresh new battery). The backlight might be a bit dimmer as the battery voltage drops, but I doubt it will be enough to be a problem. Have Fun, LyleHaze

@Lall, You are correct that a Low Dropout regulator will dissipate the same amount of power as a regular one. What you may have missed is that a 9 volt battery will not stay at 9 volts for its entire life span. I just checked the datasheet for a TI 7805 regulator. It has a 2 volt dropout, so as soon as the nine volt battery drops below seven volts, you're finished. A Low Dropout regulator would allow you to continue working the battery until the remaining voltage is lower than that. A switching regulator is the best choice, absolutely! @Screaming Rabbit The LP series of chips allows the user to run lower voltages IF they drop the operating clock frequency. 4.2 volts is the lowest safe operating voltage at 40MHz, same as the non-LF part. LyleHaze

Yes, it should work. The best way to tell how long it will last is to try it. It will only cost you a 9 volt battery to find out. If you want to make it last longer: make sure the LCD backlight is OFF. Experiment with using an Low Dropout Regulator. Turn off as many LED's as possible. Another good way to lower power consumption is to reduce the clock frequency, but then all your timing and Baud rates would be wrong, so that's probably not a good idea. Personally, I think the first time the battery went low in the middle of something important, I'd probably get mad enough to change it back to normal power. Have Fun, LyleHaze

@ mgalper Nope, all of mine are even.:) Good Luck, LyleHaze

@ SounDuke, I'm sure Sid will appreciate that. ;) LyleHaze

OK, that helps. From the start I have wondered why you need a 2.5 Amp power supply. I was afraid that you were switching relay coils or solenoids or some other inductive loads. If you have nothing more than what you described on your power supply, we can rule out those problems. Using a lamp as a power supply load will work, but you need to know that regular lamps draw a LOT more current than usual when they are first turned on. There is a "inrush" current that is needed to get the filament up to temperature. We still may have a power supply problem. the easiest way to find out would be to put the MB power supply back to "normal" and see how well it works with its own regulator supplying the power. Of course that depends on whether you have a transformer available. I'm suggesting that we start by getting a "known good" core module first, then if problems appear when you change over to your power supply, you'll have a good idea of why. Good Luck, LyleHaze

OK, let's try this again. The PIC should operate properly as long as the voltage is anywhere between 4.2 and 5.5 volts. The PIC should not be damaged unless the voltage goes below -0.3 volts, or above +7.5 volts with respect to Vss. The PIC did NOT fail because the voltage dropped to 4.96 volts. It will run fine at that voltage all day long. The PIC, like most electronic devices, IS very sensitive to voltage spikes. switching higher loads without proper decoupling can damage a PIC. Switching OFF an inductive load without having the proper parts to absorb the back EMF will definetly kill a PIC. Neither of these "events" can be easily seen on a meter. Your problem may be your power supply. Your problem may be whatever you are driving with your circuit. If you can show me your circuit, I would be happy to look it over and offer whatever input that I can. LyleHaze

dj3nk, Yes, for power supply circuits, you can usually substitute a bigger cap for a smaller one, as long as the voltage rating is high enough. The reason you usually see two caps. One polarized and the other not, is this: The bigger polarized cap is reducing ripple at the power supply frequency (100 or 120 Hz, usually) and the smaller ceramic cap (not polarized) is absorbing high frequency noise, like you might get from a digital circuit running at 40 megahertz. LyleHaze

A MIDIbox with MIOS would be a good starting point,It would provide you with the basic MIDI and display handling you would need. A DOUT module could be used to control the relays. Might need a few extra transistors, depending on the size of the relays. At that point you would get to learn programming! with incoming MIDI messages already provided to your code, all you would need to do is control your outputs in the way you want them to work. You said "I have absolutely no plan of MIDI". I'm not sure what you mean by that, but MIDI is a pretty big part of how the MIDIbox works. It's not too difficult to learn. For your application, I think "Program Change" messages would be a good start. Spend a day or two wandering around the website. Have a look at what other people are building. Read the FAQ section in the WIKI. Then decide if you want to try learning how this works. Have Fun, LyleHaze

Stryd_One, Looks like you had a long night. :o Bank selection is troublesome enough with smaller structures, but when one data structure covers multiple banks, you have a "special" kind of ugly to deal with. I am not an expert, but it looks like you have three choices. You can either constantly change banks and hope to keep up, try to calculate when the bank changes need to happen and just do them "on-demand", or use indirect addressing registers to get your data. (INDF0, etc.) How well either of those translates to C, I cannot say. There must have been some satisfaction in figuring out the bug though. That's a tough one. I need to go find some breakfast. Good Luck, LyleHaze

@SounDuke Most PC type power supplies need a minimum load to regulate properly. If it's an off-the-shelf industrial unit you can find out by reading the datasheet, but if you pulled it from a PC you have to figure it out yourself. I know that some PC parts vendors will sell a dummy load for just that purpose. It used to be the +5 supply that had to be loaded, but I haven't played with that stuff for years. It may have changed with more PC chips running lower voltages now. Good Luck! LyleHaze

Welcome! A board that converts either Pots, Sliders, or Encoders into MIDI messages would be a great cantidate for the MIDIBox. There are many similar projects that you can look at here and at www.ucapps.de. As far as a "little" project instead of a "big" one, the MIDIBox platform is modular, so you get to make it as big or as small as you want. Every project requires a "core" module, and that includes the PIC chip, a voltage regulator, and MIDI IN and OUT jacks. Which modules you add depends on whether you want Analog Inputs,(from pots or sliders) or Digital Inputs for rotary encoders. Each option has it's own advantages and disadvantages. I'm sure there's a discussion about them here somewhere. If you want to connect by USB instead of MIDI, the best choice right now is to buy a commercial USB to MIDI converter. You should be sure to get one that is multiclient compatible. Finally, I'm not familiar enough with Windows to tell you if the volume controls for those apps can be reached by MIDI messages. I'm sure that others here will jump in with that information. Have Fun, LyleHaze