matrigs

hi ! so i had the same idea some time ago to have one core which i could then use for different projects in a simple case. i soon dropped the idea for several reasons. the first thing are the connections - it's very very uncomfortable to have a few boxes on the desktop with cables between them - looks more like a guitar effect chain then a midi controller and is very inconvenient. the second problem were the connections themselves - it's recommended to have the connections to the core as short as possible (especially ground) - this system causes the problem that you make the connections longer and you can have additional problems with it.

i'm sorry for letting you wait so long for the new pics. as you can see, with the time i came to the conclusion that i don't want to have a "straight" desk so i cut the upper part and put it at an angle. the problem wsa simple - with a desk of those measures it was impossible for me to see anything on the lcd even when i put the box at a high angle. it's much more comfortable now - the only problem would be now that the lower row of encoders came very near the upper last row of potentiometers and that's wuite uncomfortable - but the shafts of the encoders are to long anyway so i will cut it and the problem should be solved. and now - every professional solders bad dream - the interior what you can see on the above picture are the faders plus the whole plate for the buttons. instead of making DIN and DOUT modules which would tak more space i soldered the chips of the DIN and DOUT modules onto that great pcb which is holdong the buttons. soldering was a bitch right but it works very fine this way. the upper part with the potentiometers, the core and the two dins. and so - the saga continues as i have another great problem with my box - the second AIN. i checked the board a dozen times - used different chips, different configurations and still i have some massive grounding problem. it's surely not the potentiometers itself because i quadruple checked the grounding and even put additional bridges to different grounding points. it's quite weird - sometimes when i turn a knob it resets the core but i checked again and everything should work fine... very very weird stuff :|

guys it works like a charm now - the high ampre 7805 doesn't even get warm now and the whole big radiator is quite useless now - but i'll leave it because i can imagine that when the case will be closed and sealed and i will play at a sweaty night club it might get hot.

okay - big update !! easter wasn't only the time for celebration and eating but also for my midiboxing. i had the time to go to my friend who is very good with electronics, he repairs actually home-audio-cinema stuff. we were sitting about 2 hours on the box making it reset all the time and we didn't really come to any conclusion at all. as we didn't have any other ideas what the problem might be (okay - in fact we were sure that it's something aobut powering but whatever) we just exchanged 7805 with a high - 2 amper version and we connected another psu (an identical 500mA 9 volt one) and guess what - works like a charm now ! so i bought myself an expensive, shiny, philips 1200 mA PSU regulated and stabilized, another 7805, a massive radiator and some thermal paste and stuffed everything together into a big powering unit - at last no resets, no problems. okay so i better go now to stuff the second ain and see if it at last starts to work ! pics soon !

some more specs ?

also - in the midibox lc topic above there is a 15v/3A psu mentioned which works fine so what about that sticking to 9 volts ??!!

i found a psu at a local shop with those parameters: 9V, stabilized, 2000mA - would that be enough? it's horribly expensive so i hope someone will be able to justify this before i throw out money and end up still not being able to fire it up.

http://tme.pl/microswitch-pcb-mounting-monostable-led-white/arts/en/a25/pb6141l-1__2.html info about the buttons above. i have two power sources - one was my old psu with regulable voltage from 3-12 volts with a maximum amount of 500mA. i used it on 9 volts on my old setup. after the lcd drained it to zero i switched it to 12 volts and it worked fine. now when i have also those buttons i connected the 12 volt 1300mA waldorf PSU which still seems not enought...

so what do i have to suddenly use two amps switched in parallel or what ? what madness is this ?

i measured it serious ! otherwise the amper meter wouldn't show me anything anyways (as far as i know from physics....) but as i said - putting 9 volts on my psu makes it a no-go. nada. could anyone recommend me something? higher amperage ?

it's getting even more weird! i just launched the whole thing with my multimeter on amper mode. now when i launched the box it shows me a steady 0,23 on the screen which i assume must be 230 mA. now when i start to launch the buttons it starts to grow and grow until it reaches 0,41 and then the box resetrs itself. but 0,41 would mean 400 mA then and the PSU is meant to be 1300 mA. and it's a proffessional PSU for a WALDORF syntesizer so i doubt that this is some hoax...

i'm a bit lost now guys... ok - i checked the voltage of the psu and it gives now unconnected a steady 17 volts!! which is quite weird because i checked before the gig and it was giving 14 volts?? weird stuff... the current is meant to be 1300 mA... is that enough? i have never checked before so i don't really know how to do that....

my setup didn't want to fire up at 9 volt after i connected the 40x2 lcd. and i really don't want to add another core to this...

okay so last week was a complete disaster when it comes to midiboxing. my goal was to finish the box without the encoders and ledrings, but with the buttons and all analog inputs until friday when i was meant to be playing before deadbeat. on tuesday i got the last batch of parts and started soldering - soldering 3 days trough not sleeping, eating, not going to school stressed about finishing on time. at thursday i wanted to add the last part - the second ain module. of course when i connected all the potentiometers and switched it on - hell broke loose. massive random events. i thought - nothing new probably due bad grounding. so i sat down at 19.00 at thursday and at 10.00 friday morning (no i haven't slept all night just soldered) i came to the conclusion that something is terribly wrong - i made a few dozen bridges to grounding points in various congigurations - still nothing. the ain module is perfectly soldered so i have no clue what was happening. but things even got worse - on wednesday i was able to fire up a half-baked version consisting of 3 rows of pots, 8 sliders and all the buttons (one ain, one din, one dout) which was the minimum i would need for the live set. now even when i completely disconnected the second ain that caused me the above problems i still had random midi data. but the ain inputs where completely grounded ! i came to the conclusion that it must be because my power source is too low! so i changed to a 12 V 1500 mA power source (really a huge thing) and still nothing - i had to disconnect the bridges with grounds of a few pots and suddenly - it worked! so i guess it's still powering. but there were more problems - now when i was switching on more than exactly 11 leds - shutdown and reset! i had to call my friend so he could bring me his behringer bcr2000 so i could at least partially play my set - but when deadbeat was rocking and playing some awfully good music i was of course setting behind him linking all the pots to my setup... and this after 3 days of non-stop soldering. so could anybody help me with this? i mean - is it the power source? but i mean i think it's not good to connect a voltage higher than 12 volt to the core? so what might be the problem ??

i also use those knobs for the pots: http://www.tme.hu/plastic-knob-for-shaft-6mm-fi-15-5mm-black/arts/en/a08/gw13b__2.html they feel very nice and have a good grip. and one important thing in them: the white line is welded INTO the knob and is plastic and not just painted on them. so they will have some very good durability u guess. i had a problem with cheaper ones where the line was just painted on them - the paint just weared off after some time. oh and additional to the pots - they also make those pots with 4 mm shaft - might be a neccessary info for those who want to make some very small midibox.

the pots are those radiohms http://www.tme.hu/carbon-track-potentiometer-shaft-6mm-radiohm-10k/arts/en/a08/p20-100r-lin__2.html they are quite cheap but they have a god feeling and there is another great thing about them - the plastic shaft - you can cut it with some sharp tool to the desired lenth so you can make sure they fit to any knob that you buy. this is a great feature also when you mount them in some different way that needs additional shaft length.

those are buttons with leds! http://www.tme.hu/microswitch-pcb-mounting-monostable-led-white/arts/en/a25/pb6141l-1__2.html the company is called "highly" and the model is "ks-01" they are not cheap but i think they are worth it. i'm saying "i think" because they seem quite delicate and i don't know how they will handle punching them in live sets - it may be that they collapse after a few sets so i'm not sure what to say about them. they are hard plastic so they have a good feeling - i don't like rubbered ones much. they feature a nice soft "click" when pressed - but you have to make sure that they are mounted stiff in the front plate so that they won't woble around because they tend to jam sometimes when you press them at a hard angle.

sorry bad link ! http://www.greenet.pl/mateo/martin/movie.MOV

hooray today is a wonderful midibox day ! i finally got the rest of my parts - 24 radiohm potentiometers, 32 fadercaps, all the hc595 and a few other parts. i made a huuuge step today - i managed to launch all the buttons at the bottom, the faders and the first 3 rows of potenitometers and guess what - no troublshooting needed at all - even my weird soldering seems to make the think function right. oh and i also added the big 40x2 lcd! here is the pic of the actual thing: oh and i also added a movie of how the lights in the buttons work. in the movie you can also see the pcb which caused me so much trouble with the holes being too far away. http://www.greenet.pl/mateo/martin/movie.mov great day !

big update today although the pics won't show it: added the lcd screen today, a row of knobs and as you can see the buttons are removed but just because i have to solder them altogether - tomorrow i should get my hc595 so i can light the babies up for sure ! as you can see i also am getting forard with the housing - although i have to admit that i might have made the whole thing too high - it's 10 cm at the front and 15 at the back. it looks much more like a pinbal table than a midibox from the side but i won't lower it before i'm 100 % sure that all modules will fit and the whole thing is wired.

i guess this link won't be helpful because it's a polish site - but i got them from there: http://www.cyfronika.com.pl/galki.htm

those are quite common here in poland - every "better" online store has them.

oh crap i have ust got an email with the price for those... my god those are horribly expensive. !

is this because of converting mills into mm ?

thanks very much that was very helpful !