[DIYbio] Re: [dorkbotpdx-blabber] Open-Source Spectrometer

also the kicad stuff is in the github repo:
https://github.com/nmz787/open-spectrometer/

and the (untested) board is on OSHPark:
https://oshpark.com/shared_projects/4HVNNy11

I still need to figure out the BOM


On Wed, Jun 4, 2014 at 2:40 PM, Nathan McCorkle <nmz787@gmail.com> wrote:
> I used KiCad, did the analog stuff and some more by hand, then pulled
> it into the http://www.freerouting.net/ autorouter for the rest.
>
> I didn't want to go 2-layer as all the low-noise analog design stuff I
> read seemed like enough reason to go 4-layer. I think I might break
> the board into two, which would let me choose different number of
> layers for each, if 4 are really needed.
>
> I'm also not sure if I need the datasheet-recommended audio
> transistor, since I didn't seem to noticed any loading effect when I
> connected my o-scope with and without the transistor. The way I've
> arranged the analog section, if I remove the transistor there's about
> 2 or 3mm between the Analog output and the ADC input... while I
> believe the datasheet may be covering cases where the CCD is in a
> hand-held barcode reader and several feet from the rest of the
> circuitry. I could be wrong though, so its in there for now.
>
> Like I said earlier, I'm not even using the second inner layer, just
> top and bottom, with an unbroken ground plane (this is what I really
> was going for, I didn't want to cut into the plane, as a lot of analog
> design stuff recommends that over the tying two plane sections at the
> ADC).
>
> On Wed, Jun 4, 2014 at 1:52 PM, Jerry Biehler <jerry.biehler@gmail.com> wrote:
>> That board does not look nearly complex enough to need 4 layers. How are you routing it?
>>
>> -Jerry
>>
>>> On Jun 4, 2014, at 1:40 AM, Nathan McCorkle <nmz787@gmail.com> wrote:
>>>
>>> So... ~2.5 years later and I just ordered a PCB for the openSpectrometer:
>>> https://github.com/nmz787/open-spectrometer/blob/master/pcb-design/propeller_square/trace_layers.png
>>>
>>> After tons of reading about electronics, it still isn't as good as I
>>> can do, but I think it's a good start to at least make sure the
>>> general circuit works as expected/intended... then I can think about
>>> noise reduction a little more. For example I'm only really using 3 of
>>> the 4 layers of the PCB right now, routing power traces through the
>>> 3rd layer or changing the layer stack with GND on both exteriors is
>>> also an decent idea, but having signals inside makes debugging hard...
>>> but I'm pretty happy with this for a 'first' pass.
>>>
>>> There seems to be a lot of room on the PCB, but I wanted to keep as
>>> much digital out of the ground plane around the analog area. After
>>> debugging I'll probably want to split the board into two, so I think
>>> the room will get diced away and lead to slightly lower board cost
>>> altogether.
>>>
>>> Right now, for this 4-layer board, 3 copies of the PCB from OSHPark
>>> was $67.... so <$33 per PCB. Previously I estimated about $46 in
>>> parts, so 46+33 = $79 with no optics (or SD card or USB cable or
>>> housing or upgraded/coated CCD window).
>>>
>>> I've added the current files to github, but I'm not sure all the
>>> libraries are there, but that shouldn't stop a determined person from
>>> googling for the missing modules/footprints! I'll figure that out soon
>>> enough!
>>>
>>>
>>>> On Wed, Dec 14, 2011 at 1:59 AM, Nathan McCorkle <nmz787@gmail.com> wrote:
>>>> Here's a first try at a block diagram:
>>>> https://github.com/nmz787/open-spectrometer/blob/master/pcb-design/openSpec_Block_Diagram_1.png
>>>>
>>>> With this design it should be
>>>> A) programmable with Arduino IDE
>>>> B) be adaptable for Ardunio shield or standalone PCB
>>>> C) ~60 fps of RAW uncompressed pixel data sent off-board via either
>>>> USB 2.0 or to the uSD card
>>>>
>>>> Cost for standalone board should be (roughly) something like this:
>>>> $2.82 * 2 - atmega328
>>>> $2.01 - WM8253
>>>> $4.25 - FT232H
>>>> $3 - uSD slot (push/push)
>>>> $20 - CCD (TCD1304AP)
>>>> $1.45 - uUSB B connector (through hole, DX4R005J91R1500)
>>>> $0.26 - EEPROM for FT232H (93LC56B)
>>>>
>>>> $10 for power management and various capacitors, resistors, and crystals
>>>> $20 for PCB, potentially 1/10th that if made at home
>>>>
>>>> Total: $66.61
>>>>
>>>> Plus $150 grating
>>>> Plus $20 aluminum/steel plate for optics (probably a high estimate)
>>>> Add 3D printed case and some 3D printed optics mounts, practically
>>>> free if you have a 3D printer
>>>>
>>>> Total $236.61
>>>>
>>>> Depending on the type of fiber you get (TOSlink vs Thor labs or Wards)
>>>> add $4-$80
>>>>
>>>> Paint/evap on some phosphor/fluorophore to the CCD to allow UV
>>>> detection - maybe about $20
>>>> (this stuff might work, though a different Lumogen is what all the CCD
>>>> UV papers talk about, this may be equivalent:
>>>> http://www.kremer-pigments.com/shopus/index.php?cat=010703&lang=ENG&product=94730)
>>>>
>>>> Add a light source - $20 UV germicidal lamp, $1 CFL, $0.1 LED, etc...
>>>>
>>>> <$350 UV-Vis spectrometer that should be good for DNA
>>>>
>>>> I just got the ADC and Hi-Speed FTDI chips in the mail today, I should
>>>> be able to breadboard them within the next few weeks... then I'll
>>>> probably try to make some PCBs with copper-clad and the laser cutter
>>>> etch method (coat copper-clad with spray paint then etch with laser,
>>>> then with copper etcher)
>>>>
>>>> I've also got a sample of the $150 grating, so maybe I can make some
>>>> progress on a 3D printed tip-tilt mount (hard for me to get started
>>>> because the point of rotation should ideally be at the center of the
>>>> convex grating's surface) for that during my Christmas/New Years
>>>> school break.
>>>>
>>>> We also got in some cheap holographic transmission grating last week,
>>>> the kind that comes in 8.5x11 inch sheets.
>>>>
>>>> Lots to do and play with!
>>>>
>>>>> On Fri, Nov 18, 2011 at 7:23 AM, Nathan McCorkle <nmz787@gmail.com> wrote:
>>>>>> On Fri, Nov 18, 2011 at 5:37 AM, Nathan McCorkle <nmz787@gmail.com> wrote:
>>>>>>> On Wed, Nov 16, 2011 at 2:33 PM, John Griessen <john@industromatic.com> wrote:
>>>>>>>> On 11/16/2011 12:10 PM, Cathal Garvey wrote:
>>>>>>>>
>>>>>>>> Wouldn't that
>>>>>>>> mean your "job" would then be to create a "shield"
>>>>>>>
>>>>>>> Your job as product developer is to deliver more bang per buck, so the
>>>>>>> $89 price of a Beagle Bone is hard to resell for cheap. And
>>>>>>> Teensy ardino compatibles are better to design on top of than
>>>>>>> straight "shield" versions with their large connectors and large
>>>>>>> size and large price for newbies.
>>>>>>>
>>>>>>>> On 11/16/2011 12:17 PM, Nathan McCorkle wrote:
>>>>>>>> What's the cheapest embedded linux board that's out there that can
>>>>>>>> bring over the 1MB/s from a 2nd micro?
>>>>>>>
>>>>>>> There's more to consider. Why not have the first micro reduce the data some
>>>>>>> also? 1MB/s is raw, very raw. A little filtering by the first micro
>>>>>>> would let you have a cheap flat pack leaded linux running micro instead
>>>>>>> of the all out ones you like. Likewise with the Wifi.. 1MB/s is letting
>>>>>>> your lab instrument do nothing but send raw data... If you reduce
>>>>>>> it reasonably, you still have plenty of room for outside re-analysis.
>>>>>>
>>>>>> In my experience no science compresses their data, except for CERN
>>>>>> maybe... I'm not sure a slow micro could handle a compression scheme
>>>>>> though. Something linux-based could though.
>>>>>>
>>>>>>>
>>>>>>> Having the first processor be a python-on-a-chip one would let users
>>>>>>> easily change the filtering routines and access raw data as well.
>>>>>>
>>>>>> I don't like the sound of python on a chip for more than a learning
>>>>>> tool, but my friend said there was a microfluidic controller that had
>>>>>> lots of MUXed pins for valving that ran with a python-on-a-chip
>>>>>> chip... he did say it didn't go anywhere, can't say it was because of
>>>>>> the chip though :)
>>>>>>
>>>>>>> There's just not going to be much interest in the world for the CCD raw data
>>>>>>> though,
>>>>>>> so why send it out? Making an open way to access it as it flies by inside
>>>>>>> the machine
>>>>>>> is better.
>>>>>>>
>>>>>>> The electronics bill of materials should be $20-$30 for two processors,
>>>>>>> one running linux, and USB ports, not including the CCD.
>>>>>>
>>>>>> Ok, TI launchpad is $4.30, has SPI, master clock at 16Mhz with
>>>>>> 62.5ns/instruction. Arduino 16Mhz (not sure on timings, probably
>>>>>> similar)... both compile with GCC (this is a feature that I'd like to
>>>>>> preserve no matter what platform) and are coded in C, can optimize
>>>>>> with assembly if needed... Launchpad is cheaper really because its
>>>>>> subsidized by TI
>>>>>>
>>>>>> Link one of those uCs to the CCD, link the CCD out to the nice ADC
>>>>>> with SPI out, link the SPI out to this FTDI SPI-USB virtual com port
>>>>>> chip (FT232H, USB 2.0, win, linux, mac drivers, $4.3), link that to
>>>>>> whatever system you want.
>>>>>> http://www.mouser.com/search/refine.aspx?Ntk=P_MarCom&Ntt=123533426
>>>>>
>>>>> Seems the FTDI USB driver is supported in rooted Android...
>>>>> http://www.ftdichip.com/Android.htm
>>>>>
>>>>> iPhone has a serial port cable, so pulling the data into the uC and
>>>>> putting it out the UART could work... @57.6Kbps you could sustain
>>>>> about 1 read per second (1 read is 59104 bits), or multi-shot into
>>>>> buffer, then long readout
>>>>> http://blog.makezine.com/archive/2011/07/59-cable-lets-you-connect-iphone-to-arduino-no-jailbreaking.html
>>>>> http://www.redpark.com/c2db9.html
>>>>>
>>>>> either uC would need some extra RAM for buffering, but this is solved
>>>>> and looks easy:
>>>>> http://www.arduino.cc/playground/Main/SpiRAM
>>>>>
>>>>> So that would instantly give you access to a huge market of Android
>>>>> and iDevices, new and used:
>>>>> display, storage, comms (cell, wifi, GPS)
>>>>>
>>>>>> Just found this via the Arduino wikipedia page, near the bottom...
>>>>>> this ($35 100Mhz ARM) or the $5-cheaper 60Mhz might run linux (uClinux
>>>>>> comes to mind) and a web server, then attach the CCD subsystem and
>>>>>> comms dongle via USB.
>>>>>>
>>>>>>> John
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Nathan McCorkle
>>>>>> Rochester Institute of Technology
>>>>>> College of Science, Biotechnology/Bioinformatics
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Nathan McCorkle
>>>>> Rochester Institute of Technology
>>>>> College of Science, Biotechnology/Bioinformatics
>>>>
>>>>
>>>>
>>>> --
>>>> Nathan McCorkle
>>>> Rochester Institute of Technology
>>>> College of Science, Biotechnology/Bioinformatics
>>>
>>>
>>>
>>> --
>>> -Nathan
>>> _______________________________________________
>>> dorkbotpdx-blabber mailing list
>>> dorkbotpdx-blabber@dorkbot.org
>>> http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber
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>
>
>
> --
> -Nathan



--
-Nathan

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