bpm controller

[ssp]

this is the reply i got from interlink about the ones they used to make for the mpc

Please see comment from engineering:

“The resistance between a common trace and a drive line is a function of applied force.  It ranges from open circuit at no force, to 100kOhms at light tough, to around 1kOhm with a very heavy press.â€

however im still waiting to hear back from the guy whos currently making them now and he is the person who invented the fsr technology

he may give me more detailed information i hope.

[ssp]

i recieved an email from one of the engineers this morning with an attatchment of hte pads details, i will have to get in touch with him again as there is no info about the pads impedance/resistance. i will have to change the ffc zif connector i have got because the pitch is different but thats ok as they are pence to buy.

if i get permission from them i will put up a copy of the pictue pdf i have been sent so others can learn from the info etc as well.

i have asked about getting a standard conductive pad array made, which instead of being an fsr would just be a set of internal conductive pads and the whole array would work as a basic momentary switch array with no fsr functionality thereby eliminating connectivity issues.

im going to ask the price on a prototype unit and take it from there, all in all this is an interesting project now as im now learning about fsr tech and about the sr chips on the dinx boards (must admit though... the sr details are some serious reading!)

[lucem]

If it's between 100k and 1k, just use a comparator and adjust sensitivity as you need it.

If you ask now what a comparator is, google and wikipedia are your friends.

[ssp]

i have looked and i dont have the slightest clue how to implement them as all im finding are ic ones. if when i cnx the strip to the din it doesnt work i will just bin it and build a 4x4 matrix of micro momentary buttons and float the rubber pads over the tops.

if i had known the sesor pad was going to be fsr rather than conductive then iw ouldnt have wasted my money in the first place, i would have just got the rubber pad and made the matrix for much much less.

[Kyo]

Can't you use your pads with AINs instead of DINs ? Those pads are designed to provide velocity why would you turn them into simple push buttons ?

[lucem]

[ssp]

Can't you use your pads with AINs instead of DINs ? Those pads are designed to provide velocity why would you turn them into simple push buttons ?

when i bought them i was under the understanding they were just simple conductive pad sensors not fsr, thereby they would act as momentarys.

lucem that would require that for each sensor pad then? which would mean 16 duplicates of the circuit? it would be cheaper and better time efficient for me to just do the button matrix board under the pads.

[lylehaze]

No need to be that complex.

It's still very likely that they will work if they are just connected to the DIN inputs and ground.

If op-amps are needed, most of the parts from the last drawing can be eliminated.

Something like this:

Aaargh! No picture upload..

We can do 4 inputs per chip, each input also needs ONE resistor, and a single pot to adjust sensitivity for the whole set. So worst case, 4 14 pin chips, 16 resistors and a pot and you'll be connected.

SIP resistors would reduce the footprint further.

But really, try connecting straight to the DIN! According to what you have posted so far, that should work fine.

Have Fun,

LyleHaze

[ssp]

thanks lyle, i have got an ain coming anyway from smash so i can try it on that also as well, and if thats a better solution get another one but we will see whats what when my kits arrive. at the moment im busy laying out the casework and working out all the pem placements and clinch nuts placements. i have to keep remembering to allow tolerance for the parts and the powder coat.

[ssp]

i have done all i can for now, so i will have to wait now for my parts to arrive from smashtv as for now im just taking some time out i have to finish fine tuning the case but when its ready i will put some pics up while its done at the lasercutters and powdercoated.

[ssp]

had some details about the pads today, so im hoping that just linking them to the din board will be fine, just in case im going to get another ain board. i hope the mb64e will let me have 2 ain boards attached should i need it.

piccy

but i also had this info from the guys at mpcstuff

1. Durability: 100,000,000 cycles

2. Max. current Input: 5mA cm2

3. Operating Voltage: 1 - 5V

4. Resistance (not activated > 20 Mohms

5. Resistance (activated 2K - 40K) using a 1.2kilo force.

6. Environmental Temp. range: -50C to + 90C, 95% relative humidity

7. Inks: Carbon = Acheson 423SS or equivalent,

Conductive Silver = Acheson 725A or equivalent,

Dielectric - Acheson 451SS or equivalent

FSR - ECM ink system (DB24,SE2 & DBE solvent)

fsr info.JPG

fsr info.JPG

[ssp]

well today the kits arrive and i can get them all built up and connected together over the next few days. as soon as i have got the core 1 ain and 1 din board assembled and connected i will connect the pad array together and see which will be taking the matrix for input.

so the internals will consist of the following items.

gm5 for midi input

2 cores

4 dinx

1 ain

1 dout

1 x mb64e for bpm

1 x midimon with small mtc display

casework is ready for the lasercutters and then powdercoating, im then going to see how much it will be for it to be silkscreened using a company here in the uk, failing that its lazertrans again.

[ssp]

im now surrounded like a kid in a sweet shop with the goodness that is smashtv's kits ;)

[ssp]

well i still have a few little placement issues to iorn out tonight, i think im going to do a little more and then not send the files tomorrow but finish up tomorrow and then over the weekend check things over for anything i missed and then send it out.

i still have 8 momentarys to place and the 8 buttons for the mb64e to place also, apart from that its pretty much finished casewise.

main dissapointment is the faders, too large for the unit really, i did find some dual gang 10k linear faders that were smaller but i cant see the tech drawing to see what sizing would be like. heres the llink, if these would work with the ain board then i may get them actually and they will make things a little better, but smaller faders again like the ones used in the spl racks would be even better.

http://www.maplin.co.uk/Module.aspx?ModuleNo=2215&C=SO&U=strat15

does anyone know if those faders on the maplins site will be fine with the ain board on my mb64e build???

the plan now is once cut, to have it sent back un powdercoated for inspection and a trial fit of everything, and then if its good i will then get the powder coating done

[ssp]

ok after a little chat with smashtv last night i will be going to use the original panasonic faders i was looking at first of all, smaller fotprint and smaller travel on the fader but it means that things will be in proportion better and the case will be smaller. as the faders are only for the filters adsr its not an important feature its so precise to have a larger travel for them.

at the end of the day they are 10k linear faders and will work with the mb64e and ain board, im trying my best to keep true to the replica design, so today i will redo the fader section and move a few things around then i will check over the weekend with a 1:1 printout onto adhesive backed paper which i will then stick to a stiff card, cut out the holes etc and mount the parts to check layout, if im happy then its off to the cutters.

[ssp]

nothing to add yet, i havent had a chance to hook things up, but i will do shortly, i am still going over the final layout on the case and checking it against the placements on my circuit boards.

[ssp]

no updates for a little while, i have to take some time out due to health issues.

[ssp]

update time:

today was the first time in a while i was able to get the kits out. so i did a cnx cable to link the core to the din and the din to one encoder to check connectivity. the thing drove me nuts all day long, i had help from wilba, nils and smashtv at one point as nothing was going right. after a couple of changes to the asm file and moving a cnx over i finally got a response by using the trouble shooting method descrived by tk, so i uploaded midio128 to the core and shorted d7 to vs and got a response on my lcd.

a few checks later and a change in the asm again and a re-test of the encoder and everything worked.

so i plan on spending a few days figuring out how to right a correct asm for all the buttons and encoders i need then trying it out.

also to check this i also disabled the ain board input in the setup file, by setting number of inputs to 0

more to follow over the next few days (i hope)

[ssp]

tonight i hooked up the fsr pad to the dinx board, it took quite a press but it worked, its a shame but i would almost have to seriously give the rubber pad a good tap for it to work, its just not sensitive enough for the din, so im looking into a conductive pad instead of an fsr pad as i dont need the force sensing type all i need is momentary.

prehaps there is a way to increase sensitivity, i think lyle was on about it with me before. its an option, otherwise i will just sell the sensor fsr matix on and buy a load of micro momentary buttons and make a matrix under the rubberpads just enough for a light press to activate each one.

more as soon as it comes

[ssp]

update:!!!!!!!!!!!!!!!!

well speaking with nils it took 5 mins for him to suggest how to sort it out, he suggested a small 10k pot , i used one from my spare core kit, i wired the wiper to vs and one leg of the pot to the din pin and also from there to the fsr leg in.

i then had to adjust the pot so that it was so close to the point it was in the "off" state, then a quick press of the pad and bingo it works!! just with a gentle touch

all i can say is many thanks to nils as it would have led to me buying a lot of items i didnt need.

photos tomorrow!!

[ssp]

using serge's mb64e editor software i was able to do a test sysx dump to and from the core perfectly, i did a button learn and then a re-assign on what it did etc. all worked perfectly.

i have now ordered a set of alps RK09K11310KB  these are minature 10k linear potentiometers, these will be mounted to the rear of the case to allow for hands on trimming of the pads. the only other cnx on the rear of the case will be a usb port, power in port and also underneath will be a flap for the bankstick/ card to clip into, i intend to have a clip or slot in bank stick in the unit.

enough babbling i got building to get on with!

[ssp]

busy day converting lots of tech stuff from inches to mm becasue lots of tech schematics i have got are in inches adn as i like to work in mm i had to convert it all, took a while but its all done now.

the main thing was getting all the cutouts and mounting points for the akai mpc pad matrix sorted out, i had to get this exact as the mount plate will have guide holes in for the location pins for the pads and the fsr matrix.

the 4x4 squares are the points where the pads come through the case, the centre points are the direct centres of the fsr marix that sits below it.

here is the fsr matrix from scl

here is the underside of one of the pads, the underneath is coated with a 3M adhesive to help it stay in place on the original akai mpc mount plate.

the plate that will sit behind this pad will probably be 2-3mm thick the reason being so that it doesnt move or flex under constant hits and use, however a foldback plate may be another option which could be made out of 1.5-2mm thick material, the outer edges of the plate being folded in on itself to form a u channel where the mount pem's run through to nuts on the otherside.

i have used serge's mb64e editor with the core now and have been able to learn a selection of dials, edit and dump back to the core fine. all i have to do now is finish the casework this weekend and get it sent off for cutting next week., i wont have it powdercoated yet in case i have to have anything changed.

the plan is to do a full scale 1:1 printout using my big plotter and then transferring it to some card, cutting the holes out and test mounting everything, anything thats not right can be edited prior to the metal being lasercut and folded.

more to follow.

more: just did a 1:1 printout of this matrix assy and laid it up on the fsr and pad matrix they all fit perfectly first time wich is great, this mean i can now transfer this layout to the case ready and mark off that as done on my list, its just tidying up the placements and doing the transport buttons next along with deciding where the trim pots for the matrixtodinx board will go.

[Flying Panther]

the plan now is once cut, to have it sent back un powdercoated for inspection and a trial fit of everything, and then if its good i will then get the powder coating done

I'm curious where you will get your panel made? As your Hu-Mon panel looks very professionally done as well ;) And does the company do everything (lasercutting, bending the sheet-metal, powder-coating), or do you work with various companies to get this done?

[ssp]

I'm curious where you will get your panel made? As your Hu-Mon panel looks very professionally done as well ;) And does the company do everything (lasercutting, bending the sheet-metal, powder-coating), or do you work with various companies to get this done?

well the hu-mon was done using a company that uses solidworks for its cnc and laser cutting machines as standard, the case work was done as sheet metal objects and then its unfolded in the software, the pem locations mapped and then its dumped to the relevent machines. the company then used my files and sent them to the cnc folder to make the necessary bends in the metal all within the specifications i applied to the plans, they then get sent to a company they use all the time and was powdercoated.

the bpm unit will go through the same process, however prior to powdercoating i will check the casework and make sure im happy then have it powdercoated, then i will either have it screen printed or i will lazertrans the graphics to it then clearcoat the panel.

i now have several companies to choose from for the laser cutting and cnc work etc this time i will see which one will offer the best quality at a suitable price.

once i finish this unit i will then dump all the files, plans and specs i have into a thread or as part of the wiki, whatever i need to do so that other people can build a similar controller using all the information i have gained since starting it. and who knows i may finish the hu-mon as soon as i get my bloody wood..

[Flying Panther]

Thanks for the elaborate answer :) Solidworks really is a nice piece of software to work with imho, nice to see that companies can use it aswell.. Saves a lot of effort on converting things to the right format!