Cost to build your edrum ?

[Jeph]

Hey all,

I would like to know what is the budget you've put / will put / ready to put in a project like the one Admir made. I want to make my current stand alone project as low cost as possible ( unfortunately its impossible to get it for free ) and if possible around the same price as Admir edrum.

I will release all my schematics, layout, programmation for free but to know how much money people are ready to put out will guide my selection of components. As of right now, the big parts of the project aren't cheap but aren't costy either. If we are lucky, most of the costy components will still be available in sample.

Here's a list of the key pieces price on digikey (price in US$):

TMS320C6720 (DSP ) : 10.83$ (available in sample right now)
PCM4204  x4(analog to digital converter) : 13.24$ each so 52,96$ in total (available in sample right now)
PCM1771 ( digital to analog converter) : 3,94$ (available in sample right now)
LCD screen(depending on the model) : ~20$

+ the cost of semiconductors components (capacitor, resistors, connectors,etc)
+ the cost of the board (to be determined)
+ the cost of the memory ( ~20$ all in all)

As you can see, if by the time I get a working product and the components are still in sample, you can save a lot of money ( 10.83+52.96+3.94 = 67.73)

My goal was to make the project under 300$ CAN (260$ US with the currency conversion as we speak).

Is 300$ too much for you guys or is it cheap or inbetween ?

With 4 PCM4204 , we get 16 channels ( 4 channel per ADC) . I could make a model with 5 PCM4204 or even 6 PCM4204 ( 20 channels / 24 channels)

I could also go with low number of channels (8 or 12 channels)  if people think that 300$ is too much. I can also make different models with differents number of channels ( but the first one will probably be 16 channels as i first intended) .

Anyways, if you have any interrogations/comments/ suggestions , leave them here or on my other thread.

Thanks

[drummer_dave]

personally if i could have the capabilities of lets say a roland TD10, 12, 20 for less then half the cost i would be in...
i know its more work but it would be worth making the unit expandable and have  maybe some analog boards with 8 connectors and 2 A/D's per board the more inputs the better for me,   have a couple different software versions...  im sure this type of thing will take some time to evolve, when making the pcb i would take all extra i/o's and run them to a "for some other purpose" header.   o ya... i would be happy to see a digital audio out not sure what your digital audio is I2S maybe but a simple SPDIF,  AES/EBU etc... output would be great for me (and maybe just me)
I would in the digital audio world, so i love to see that as an option.  ok maybe im getting ahead of myself this is your project... if you post the schematics maybe i will have to do my own layout and add these things    

Dave

[Jeph]

Personally, i don't know much about e-drums from different companies, so could you be more specific when you say "personally if i could have the capabilities of lets say a roland TD10, 12, 20...". What are the feature you'd like to see? I really don't mind implanting suggestions as long as they are detailed. I've read a bit about Roland TD10 today at school and i think those features are doable given enough time. But i'd like to have more specific details on what you are looking for in my project. The more suggestions and details, the more complete the drum can be.

As for the expandable feature, right now, the way we designed our boards, we have 1 board for DSP/SDRAM/FLASH , 1 board for PCM4204 x2 (ADC) and 1 board for PCM1771 (DAC). Everything we need is included except power supply which i'm trying to get the best result out of it( on our board, we use linear regulator but we are looking into different DC switching power supply ). Maybe we'll do a small power supply for each board to reduce noise inbetween device coming from the power. Each ADC boards mean 8 inputs. If i keep the boards modular, it's already expandable to an extent. I don't have infinite McASP line even though i could multiplex them by doubling the sampling frequency to 96khz. That means we can get 2 times more acquisition in the same period of time for 48khz.

For the output, the PCM1771 takes left-justified or I2S and switch it directly into analog signal ready to be played in headphone. But the DSP also support natively SPDIF format and some other format too so it won't be too hard to implent this if people really wants it. Another feature of the PCM1771 is Audio Mix pin. You can take an external source of sound ( mp3 player for example ) and plug it directly on the chip ( it's mono though) and it will add the external source with the sound being played, meaning you can play along your mp3 player or click track. 

[drummer_dave]

great to hear you are open for input.   an audio mix in would be great (and is a feature in most newer modules).  as for other features
LOTS OF OUTPUTS!!!  My TD8 has 4 and i dont find it enough...  8 programmable analog outputs would be sweet! or even if they were not programmable have them grouped accordingly.   yes it would take a couple more opamps to drive the output stage but i think its worth it, especially when it comes to using it to record with a mixing board.  I like having faders (60mm or 100mm) and knobs to twiddle levels... yes more work, but set the pot to a ADC port and correspond the varying voltage to level...  yes its easy for me to sit hear and tell you how to do it, sorry .  Headphone output with level control (capable of driving standard studio 32ohm headphones)... um what else is on my wish list, midi in/out lol.  o ya i know im being a pest but can the card reader read High speed cards (ie. greater then 2 Gb) if not maybe have the option of two card slots...  usb update capability for firmware is always so so so so so nice (i implement it in almost all my projects since i learned how to do it).

basically make a TD20 and you will make lots of money hahaha.
heres a pic of the rear of a TD20,  spdif out, 8 direct outs (definitely easier then programmable)  15 inputs (but more is always better)
great thing about the vdrum line is the editing of parameters (shell depth, tension etc...)  that a bit more to deal with...




ill shut up now... thanks for humoring me.  like i said im just trying to come up with as many ideas as i can, regardless of what you implement you will still have a great project.

   Dave

[Jeph]

Hey i don't mind all those idea as long as you understand that there is work and it will take a time to achieve those thing. I'm more than happy to oblige to your requests, else I wouldn't ask you for your input. I'll quote you to respond to each element.

an audio mix in would be great

As i said, the DAC already have a MONO Audio Mix if that's enough.

LOTS OF OUTPUTS!!! My TD8 has 4 and i dont find it enough...  8 programmable analog outputs would be sweet! or even if they were not programmable have them grouped accordingly.   yes it would take a couple more opamps to drive the output stage but i think its worth it, especially when it comes to using it to record with a mixing board.  I like having faders (60mm or 100mm) and knobs to twiddle levels... yes more work, but set the pot to a ADC port and correspond the varying voltage to level...  yes its easy for me to sit hear and tell you how to do it, sorry Wink.

I'm not sure how they are supposed to work. You have to help me out here. With my knowledge i would say it's an audio output (meh!) but my question is : Is it for a single module (the snare for example?) or is it for all the sound ( if you hit the kick and the hi-hat at the same time ). I would like to have more information on that please. For the output amp, it doesnt bother me at all.

Headphone output with level control (capable of driving standard studio 32ohm headphones)

Right now, the chip we are using don't have volume control but it's SPI counterpart have it and it's planned to change it. One thing though, the chip is made for at least 16 ohms headphones, but i'll do some test for the 32 ohms headphones.

um what else is on my wish list, midi in/out lol

It's an interesting feature. I'll have to check what it takes to be able to integrate midi as i've never touched this protocol. Right now we are using .WAV but i'll try to have more sound format compatibility.

[quote
o ya i know im being a pest but can the card reader read High speed cards (ie. greater then 2 Gb) if not maybe have the option of two card slots
[/quote]
I haven't tackled the SD card yet, but i'll see what i can do about that. More info to come.

usb update capability for firmware is always so so so so so nice (i implement it in almost all my projects since i learned how to do it).

Planned. I want to make the board Programmable In-System to make my life easier.

basically make a TD20 and you will make lots of money hahaha.

Maybe in a distant future. I work on this project as a part time project and a hobby. Companies like Roland have a team of people dedicated to the task. Maybe i'll pick up a team at the university this autumn (which would be great)    But I'll see how it goes. One thing though, i don't plan on going strictly paying product. I like when people share knowledge with me (like this website) and i want to give back too because that is how we learn. Anyway , i have to finish first!

heres a pic of the rear of a TD20,  spdif out, 8 direct outs (definitely easier then programmable)  15 inputs (but more is always better)
great thing about the vdrum line is the editing of parameters (shell depth, tension etc...)  that a bit more to deal with...

I plan on making a 16 channels model first. I want to have each input programmable except maybe for the hi-hat & hi-hat pedal because they act differently than the rest of the set. Each input will be mono, but if i make it input programmable, you'll be able to make stereo output. I'll start from there and later add special cymbal input to make them choke able.
About the vdrum editing parameter, well it will come last because it's fine tuning.

Well, that's it. I'll update you soon. We should have our DSP board next week.

Until then, cya! 

[drummer_dave]

great to see a fast response Jeph

-mono mix in is cool with me, like you said, its nice to plug in a MP3 player to play along with, i would say if mono isnt enough for people then they can use a off board mixer
-Outputs, if you look at the td20 it has 8 analog direct outputs grouped as follows
out1 = bass drum
out2 = snare
out3 = hi-hat
out4 = ride
out5 = Left side toms
out6 = right side toms
out7 = left side cymbals
out8 = right side cymbals

i would say thats pretty good grouping (sort of limits you if you assign some inputs other then what its default is)
i know me personally my kit is usually set up  with a acoustic eqivalent as 8", 10", 12" 14" 16" and 18" toms, double bass (its nice to have 2 seperate pads for this so you can off tune one just slightly...  probably something to worry about down the road)  2 or 3 crashes, 1 china, 1 or 2 splashes, snare, bell...
that fills the inputs pretty quick, but if there is a midi in then you can always hook up Admir's eDrum (which I currently have and use 2 of) to extend the inputs quite easily...

-headphone out, there are spi/I2C volume control IC's  to name one off the top of my head is the PGA2310 or ssm2160 (more $$$) which you just add before the headphone amp chip.  if it works with 16 ohm's it will be fine with 32ohm.  you can also use opamps to drive phone's, or class AB push pull configuration...  OPA134 should work but maybe not best idea for keeping cost down.  if you like i can try to go through my line level and headphone amp schematics and send you some.

-midi in/out
like i mentioned before midi is pretty important in the electronic drumming world and would be greatly missed.  im sure if you ask nicely Admir as well as
aquawicket they can probably direct you in the right direction.

-sd card
have fun looking into it, just thought i would mention the difference between the 4Gb/8Gb cards vs the 2Gb and under, can be a unexpected pain if want to load up a 8Gb card but the protocal you have written will only work with the 2Gb...  but 2Gb and under is still perfectly fine.

-usb update
RIGHT ON!

- chokable cymbals is a very nice feature, even if its just for the crashes...

I definitely understand that you are only one man, there is alot to figure out and its never as easy as it sounds.  My programming experience is limited to mostly control systems using pic micros...  I realize the overwhelming amount of work ahead of you.  I am willing to offer any help I can, if you want it.  I did the digital board to interface for my companies $10 000 pre-amp...  display interfacing I2C,SPI, RS232, working on USB stuf etc...  also analog electronics is really what i enjoy, if you want any more input or suggestions for the analog stages i would be more then happy to look into it for you.  well i best be off.  glad to hear i havent scared you off with all my requests/suggestions. 

I am just suggesting what i would call my DREAM module. Again you have to weigh  cost vs needs/wants.  if i was to ask for only one thing then i would say that MIDI is a BIGGY!

  all the best
   Dave
         



 

[Jeph]

-Outputs, if you look at the td20 it has 8 analog direct outputs grouped as follows
out1 = bass drum
out2 = snare
out3 = hi-hat
out4 = ride
out5 = Left side toms
out6 = right side toms
out7 = left side cymbals
out8 = right side cymbals

Thanks for clearing that up. I'll see what it's possible to do with what i have right now. The problem i see with my microprocessor right now is the "lack" of McASP lines (16 serializer is a lot but still) I need to use those line in Inputs and Outputs. That means that the more input channel i have, the less output channel i have and vice versa. I will definitely have to look into it. My friend who've worked with me on the project told me there is a way to multiplex the McASP which would solve the problem because we would need only 4 McASP serializers to have 16 inputs. Leaving 12 McASP for other use. It's on my checklist.

i would say thats pretty good grouping (sort of limits you if you assign some inputs other then what its default is)
i know me personally my kit is usually set up  with a acoustic eqivalent as 8", 10", 12" 14" 16" and 18" toms, double bass (its nice to have 2 seperate pads for this so you can off tune one just slightly...  probably something to worry about down the road)  2 or 3 crashes, 1 china, 1 or 2 splashes, snare, bell...
that fills the inputs pretty quick, but if there is a midi in then you can always hook up Admir's eDrum (which I currently have and use 2 of) to extend the inputs quite easily...

The problem i see though with Admir's Edrum (correct me if im wrong) is that is uses the serial port and my DSP doesn't support it. But we plan on hooking up a MSP430 to the DSP and im pretty sure i'll be able to deal with that. RS-232 isn't complex at all so it will probably be easy to incorporate it.

-headphone out, there are spi/I2C volume control IC's  to name one off the top of my head is the PGA2310 or ssm2160 (more $$$) which you just add before the headphone amp chip.  if it works with 16 ohm's it will be fine with 32ohm.  you can also use opamps to drive phone's, or class AB push pull configuration...  OPA134 should work but maybe not best idea for keeping cost down.  if you like i can try to go through my line level and headphone amp schematics and send you some.

We are currently using PCM1771 from texas instruments, but PCM1770 is the same chip with SPI control though so i will be able to control the volume. So don't worry about that

-midi in/out
like i mentioned before midi is pretty important in the electronic drumming world and would be greatly missed.  im sure if you ask nicely Admir as well as
aquawicket they can probably direct you in the right direction.

Added on my checklist

-sd card
have fun looking into it, just thought i would mention the difference between the 4Gb/8Gb cards vs the 2Gb and under, can be a unexpected pain if want to load up a 8Gb card but the protocal you have written will only work with the 2Gb...  but 2Gb and under is still perfectly fine.

I don't think it will be a problem to have more than 4GB cards but i can't assure it will be at its full speed though. But the way the sound will work, you won't need to have the fastest access because sounds will be loaded from SD to SDRAM directly.

I definitely understand that you are only one man, there is alot to figure out and its never as easy as it sounds.  My programming experience is limited to mostly control systems using pic micros...  I realize the overwhelming amount of work ahead of you.  I am willing to offer any help I can, if you want it.  I did the digital board to interface for my companies $10 000 pre-amp...  display interfacing I2C,SPI, RS232, working on USB stuf etc...  also analog electronics is really what i enjoy, if you want any more input or suggestions for the analog stages i would be more then happy to look into it for you.  well i best be off.  glad to hear i havent scared you off with all my requests/suggestions.

Thanks for the proposition I'll see how it goes and if need be , i'll look for help.

I am just suggesting what i would call my DREAM module. Again you have to weigh  cost vs needs/wants.  if i was to ask for only one thing then i would say that MIDI is a BIGGY!

As i said before, i don't mind making it big as long as people understand that for every feature they want added, i need to take time to make those feature. One thing though, eventually, i will release the source code, schematics,etc (probably with my first working module). Then people will be able to make their own modification(given the right knowledge). People will be able to have their own modification and hell maybe(odds are against me ) someone will be better than me and make a better drum module. That's one of my goal to share and hope for people to use the knowledge better than me.

With that said, i'll keep you guys updated. There is a downtime expected, until i get my universal programmer this june. But i have lots of reading to do so i will do that in that downtime.

That's it!

[drummer_dave]

dont worry about the the rs232,  i would connect them via midi, the rs232 is nice for hooking up to a compter with a serial port, but the midi is much more valuable.

as for port expanding you can always look at port expander's like  pcf8575 (16 i/o's over just 2 I2C line's)  or even use some 7400 series ttl or cmos chips...
bla bla bla... i like electronics, so i tend to talk about them when ever some one will listen. sorry 

    Dave

[Jeph]

ive just read about midi a bit on my favorite first page of information when doing research (Wikipedia) and there seems to be a lot of different MIDI format (more exactly extended formats) Which one is Admir Edrum using?

[admir]

ive just read about midi a bit on my favorite first page of information when doing research (Wikipedia) and there seems to be a lot of different MIDI format (more exactly extended formats) Which one is Admir Edrum using?

Just standard v1.0 MIDI, nothing special is needed for edrums: note-on, note-off, aftertouch, etc.

[Jeph]

Alright thanks admir.

I'll have to rethink my programmation because right now, the way my edrum works, it's an analog signal converted into digital data and the DSP detect which channel it comes from (snare for example) and play a snare sound that is in the memory. But anyway i'll keep on reading and see what's coming up. Also i will put up a small video shortly of my project so you guys can see what is working right now. My sister gave me her old camera and i can make some decent video with it.

[Jeph]

Also i would like to know where you've taken your information about midi admir? A few pointer would really help me out to a better understanding of midi 1.0
thanks!

[admir]

Also i would like to know where you've taken your information about midi admir? A few pointer would really help me out to a better understanding of midi 1.0
thanks!

The best thing is to go to MIDI Manufacturers Association site:
http://www.midi.org/techspecs/midimessages.php

And here is one really helpful site also:
http://home.roadrunner.com/~jgglatt/tech/midispec.htm


Regards,
Admir.

[Jeph]

Thanks Admir.

I've read a lot about midi and i think i've figured out how most of it work. The thing i am at right now is how the midi file is made. Where are all the info in the file. Most of the site i find only tell how midi work in general (Note On Event, Aftertouch Event,etc) but when it comes to the part where the sound is played, all i get is hook it up to a computer or the sound generator is in the device... it frustrates me a bit but hey! that's part of the job. I'll keep on reading.

[deadsoulf1]

Hey, guys! 
I'm realy happy I've login at last! There was a lot of troubles,
activating my e-mails.
But I'm here now, Yea! )))

Listen, where are Jeph? Is anybody know, what has happen to his project? It's greatly important!