intellijel

I would leave the button matrix as is (they use minimal current) but just use the darlington pair array to sink the current of the led cathodes. The signal source may be from the 74HC595s but they would just be switching on the transistor current sources with minimal current (if you use transistors to source current). You would not need this as you stated if you are happy with 10ma or so per led colour, however I am lighting rgb leds through those thick button pads from sparkfun and I have found I need a lot more current. The issue is that because of the array, one pin of a 74HC595 may be lighting up to 4 leds at a time (granted with PWM this will minimise power requirements). A transitor array instead of a darlington pair array would probably suffice for the LED anodes.. cheers, Danjel

Has anyone inmproved on the design? I thought a simple obvious way to supply current for higher power LEDs is simply to use a bunch of darlington pair array ICs like the ULN2001A in series with the DOUT module pins driving the LED anodes (the ULN2001A would be sourcing the required current, up to 500mA per output). A simple npn transistor array may also be adequate if each individual led colour (e.g. the "red" led of an rgb led) is drawing less than 200mA current. You would probably also need a darlington pair to sink all the current at the DOUT pins driving the LED common cathodes. There will be more current to sink here than what is being sourced for the individual led colours which share a common cathode. Thoughts on this? p.s. I remember reading a comment before from TK that he was suprised there was so much interest in the led/button matrix. Are you kidding? Name me a commercially available, AFFORDABLE, sequencer that has that feature? It is such an obvious way to provide intuitive and quick interaction with a step sequencer, I would imagine that this is actually the most popular addition to the SEQV3 feature set! It would definitely be cool if more work was done on this... I had recommended before using a maxim led driver chip (TK pointed out that maxim chips can be too hard to source sometimes and he wants to keep midibox designs easy to source parts for) but there has got to be some commonly available chipsets that can be used to make this task easier.

I don't mean getting pcbs made, I am referring to the boards with an array of holes (for prototyping). I find it faster to wire wrap or solder a well made protoboard if one is making something like an array of buttons+leds. I should start looking at getting pcbs made though (just to save time) cheers, Danjel

Look for a good source for cheap but good quality PTH proto boards (the type with holes that are vias (copper the whole way through, e.g. way stronger). Don't know any brands/brandnames to be checking out. I will be using these for my button/led arrays in Sequencer and other projects. or any other recomendations for prototype circuit boards.

"Never plug a PIC into the socket so long you haven't done the initial hardware checks, and so long the red Vpp LED and/or the yellow Vdd LED lights up!" This sentence does not make any sense. Is this what you mean? "Never plug a PIC into the socket if you haven't done the initial hardware checks. Also, do not plug in a PIC if the RED/YELLOW LED's are lit up." ? OR "Never plug a PIC into the socket if you haven't done the initial hardware checks. Also, don't plug in a PIC until the RED/YELLOW LED's are lit up." ? thanks, intellijel

correct but I can just use a usb-parallel adapter (inexpensive)

Just wondering what the differences/enhancements/mods were at Mike's Elektronseite for midibox boards? For instance I noticed he is selling something called the Mplus_V1 Kit (which just looks like the Core, anything special about it?) cheers, intellijel

Looks like http://www.mikes-elektronikseite.de/shop_englisch/index.htm Has kits for the newer burner (quick to build).

The above mentioned docking station is $70-80. I could buy just a usb to parallel cable for not much money, however I would still have to build the Pic Burner. As aforementioned I am trying to save as much time as possible. Spending 1-2hrs building a little board is more expensive than just buying a pre-made one. However, I do have the pcb board and parts for the older JDM module (from smash tv). Are there quick mods I can do to turn this into a pic burner? (I remember one thing I saw was just adding a 10k pullup somewhere) The other advantage of buying a burner like pic kit 2 or one of those clones is that I can use it for burning a wide variety of other pic chips for other projects. cheers, intellijel

The brenner8 looks good but I can't read german. I was thinking of something like this as well: (this is a clone of a PicKit 2 with a breakout board that has Zif sockets on it and a header to connect to the programmer). http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&ih=008&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=180079102120&rd=1&rd=1 I could also just purchase a microchip pickit 2 and then buy or make one of those zif socket breakout boards. I have tons of projects on the go and I am looking to buy ready made boards whenever possible or well put together kits (like smash tv). What little free time I do have will be used for the mechanical aspects (wiring pots/switches, layout design) which consumes the most time anyways. cheers, intellijel

I am on a laptop that only has usb and fw for i/o. I need to program my pic chips by usb and have been wondering about buying a microchip PicKit 2 and then building or buying a little board with a Zif socket and ICD header so I can quickly and easily program my Pic chips. Anyone had experience with this? Is there a board I can already buy that has the appropriate sockets for the pic18F4620 and a 6 pin icd header for connecting to the PicKit 2? cheers, intellijel

I saw some links a few months ago to some preliminary front panel designs... anyone have some nice designs they want to share? cheers, intellijel

To TK (and others following the development of the SEQV3) On the monome page they had some documentation about using diodes as part of the button array to avoid the problem of "ghosting" "...button system uses surface mount diodes to prevent ghosting. this method lets us discretely detect press and release of all keys simultaneously. diodes are placed by hand after solder-pasting (more information on this in the next section), then baked in the toaster oven." http://www.dribin.org/dave/keyboard/html/ghosting.html Also, in your sticky you mentioned there were some new button/led options? cheers, intellijel

Just confirming that I can use the midibox PIC burner as is for programming the PIC18F4620. cheers, intellijel

You should also add four dedicated buttons/leds for choosing between track groups: 1. Tracks 1-4 2. Tracks 5-8 3. Tracks 9-12 4. Tracks 13-16

I am in Canada so I will probably avoid orderign from Australia :P You can get OLED/PLED displays in North America from www.crystalfontz.com. But they do not have 40x2 modules and all of their LCD modules are very expensive (but apprently high quality too). cheers, Danjel

ha! I am already on the Synth-DIY list (excellent, really helpful community). As for porting to a 32 bit uC, I think I would rather just port to a better family of uC's like the AVR Atmel chips. My strengths are in hardware design and mechanical work, I am not so much of a programmer anymore (but trying to rebuild my skills). I would like to find something like the MIOS that already exists for another project. However, maybe porting the MIOS would be a good project for rehabilitating my dormant programming abilities. cheers, intellijel

I totally support the midibox project and admire the efforts of all those involved in maintaining a mandate to provide low cost, easy to use, open source projects. However, I keep encountering limitations in using the PIC as a microcontroller and in using/adapting a base set of boards in a modular fashion. I am interested in working on more advanced projects with more powerful uC's possibly more expensive (maybe evene surface mounted components) and designing custom boards. Is there a forum for people developing more advanced music technology prototypes? thanks, intellijel

cool, thanks TK! Checkout this led matrix driver chip: maxim MAX7221 Could make things easier for your design. I'll be building this sequencer over the next few weeks. thanks!

Can you get VFD that have compatible interfaces to the LCD modules (HItachi standard)? e.g. YOu can just swap out an LCD for a VFD?

I am investing money into my sequencer project to make it very very functional for live use. One of the features I would like is OLED or PLED display as they have a really wide viewing angle. I checked out crystalfontz but they only have 20x2 modules. Anyone know where else I could find them? If not, what is the best 40x2 LCD screen I could use? (price is not an issue) thanks! Danjel

I haven't built a version of the SEQ yet but I plan to build V3 with the LED/BUtton matrix. I have already ordered an array of buttons+PCBs from SparkFun in anticipation. I assume the rest of the project will use all of the same hardware as the older SEQ except that there are some restricted options (e.g. Only 2x40 LCDs will be supported). Anything else I need (e.g. other stuff to go with the button/led matrix)??? e.g. MAX7221 led driver I would like to offer my services to beta test it if I can get the hardware together quickly. cheers, intellijel

I think this will only accomplish one half of what I was hoping for. This gives a way to send pitch/transpose messages at whatever rate I would like (using the seperate CC track) but there is no way to have the pitched notes wrap around the lowest or highest value not limit (another way to describe that is as "octave quantising"). yes that's another way to look at it, just look for creative solutions using CC coupled with MAX/MSP patches. I see... having only 7 bit values will definitely limit the PB. It may be cool in a future version to have high resolution pitch bends/CC and then have the ability to reduce the bit values (cool effect if one can set the bit depth, it would provide a way to emulate sample and hold) hmmmm seems like a lot of problems come back to memory limitations of the pic. Myself and soem firmware programmers I know were already impressed that you managed to fit a whole sequencer in there. What about making the option for a second core module to be used? Create a set of extended features that can be realised with the extra processor+memory? Or are there plans to use a different micro proc. in the future? does this mean that it is not possible for one note to be sustained overtop of another step? e.g. If step 1 has a long sustained note (longer than a step lenght) and step 2 has a short note, would step one sustain and then step 2 would play overtop of it while it is still sustaining? ok that sounds cool. I still have personally found negative/positive delay to be realy useful. anyways, sounds like you have done the best you can. Still has awesome features and will be a tiny fraction of the price in comparison to a Notron, P3 or Octopus. The illuminated step pushbutton extension will definitely increase it's allure (I just hope SparkFun get their act together and produce some more PCBs...they are losing money!) cheers, intellijel

Hey Thorsten, I think you have taken my questions the wrong way! I am in no way demanding that these features be implemented. Nor was I trying to imply that I would only build this sequencer if these features existed. I have been following ucapps for several years and have built a couple of midi controllers and a midi2cv so far. I am also a hardware design engineer and have been recently doing research into building a sequencer. From what I can see, many of the features I would like are already implemented in your designs (thanks to your hard work) so I am thinking it will be a better investment of my time to examine what you have created and look at ways to modify or adapt the design. I am just trying to clarify what features exist (or what they may be called) and indirectly offering some ideas that you may want to consider adding (to this version or future versions). I did not realise there was an exclusive list for Seq 2, I will try to sign up for that. ok this is kind of cool: Let's say I had a 16 step pattern that is looping. If I put a tranpose of +2 on step 1, then everytime the pattern repeats, all notes following the transpose message will be transposed +2. So after one pass everything is +2, after second pass everything is +4, after 3rd pass through it would be +6 etc. What the notron does is provide a low and high note transpose limit that cause the cumalitive tranpositions to "wrap" around once they have reached a certain octave (e.g. if it has reached it's high limit, it will shift all notes above the cutoff point to whatever the lower limit is and start rising again, in this way you get amazing moving patterns). The limits make sure the pattern does not keep transposing upwards or downwards to infitiniti. You can see an example of this in the no!tron (a reaktor ensemble) This is again based on the concept that if you pitch something up or down, it stays at that new pitch unless you tell it to change. So if I had a pitch bend of -3 on a step of my pattern, everytime that step is reached, the whole pattern will be bent down an additional 3 semi tones. -3 then -6 then -9 So if you set one step to be -3 and then another stpe to be +3 bend, the pattern will be tranposed down and then back up by pitch (the net pitch bend is zero at the end of the pattern). If these steps also set different transpoistion rates (slide times) then you will get cool organic slides in the sense that the pitch bends will be moving at different rates for different notes. If a step has a pitch bend event AND its gate length is long (and you are controlling a polyphonic synth patch) you should get long gliding notes overtop of your sequence. Sustain: Each step holds its note on (until perhaps the step is retriggered, yo don't want midi overflow) When combined with pitch bend events you will get liquid riffs. Kill: The same as suddenly cutting your midi cable in half, e.g. note on messages to a synth will sudenly be stuck. This is a cool way to get a pattern to suddenly have a strange breakdown... the effect it causes is also dependent on your synth you are controlling. e.g a pattern will suddenly be paused holding whatever notes were on at the time This would be nice to have. Most sequencers get notes to sustain longer than a step length by tying steps together. In the case where your seqencer has indivdual control over note length, combining a long note length event with a pause of a certain step amount will give cool sustained notes. Eg. Step one of a 12 note pattern has a 4 step pause and it has a long note event. If you played the pattern, you would hear a sustained note for a 1/4 of a bar (4 steps of a 4/4 pattern), then it would play the remaining 12 notes (a weird way to play a 16 step pattern using only 12 steps). If you start to play around with timing options like this you can begin to generate some really interesting patterns. Yes I agree, I hate menus and would like all functions (whenever possible) to have dedicated controls. They way you have implemented things so far is great. Depending on what new events/options are available per step I would add some more dedicated buttons to access those options. This kind of thing may not be so hard for me to add on my own if it is not integrated into the core design. great! so I could go to one step of the pattern and set it to be delayed by a certain negative or positive amount and then go to another step in the pattern and do a different +/- delay? As aforementioned I am in no way making demands! just asking some questions :) So this is a big part I guess since you want to remain compatible with the existing design. hoever, with the addition of the matrix led/button option there may also be the opportunity to add more dediocated controls for some of the new features.

Looks like great work is being done! I have some questions about v3: 1. ETA? (when do you think this will be released?) 2. Is there a cumilative transpose function (like on the notron)? 3. Chord strumming option? 4. Cumilative pitchbend with transposition time set per step? 5. Will there be additional or different hardware (PCBs) used from the older version of SEQ? (other than the matrix led addon...time to shop at Sparkfun!) 6. How about a function to sustain or kill all notes on a channel? 7. Option to pause at a particular step for a set number of step lengths? 8. Individual shuffle settings per step? 9. Skip step function? (combining step pause, shuffle and skip step helpds create awesome swing riffs) 10. Option to quantise individual chords to a scale or not? thanks! intellijel (lookign forward to this! I have wanted a Notron for years and this may be even better once it is all working)