Cyton Component Questions

vivitribalvivitribal
edited October 2017 in Build-it-yourself
Please forgive me if I'm asking stupid questions.  I've been desperate to get my hands on an EEG for awhile but I could never afford one.  This project has finally made it possible but I want to make sure it works the first time.  I have some experience with electronics but I've never done anything as complicated as the OpenBCI board.

I'm looking to build my own OpenBCI 32-bit board but I had some questions on the components.

What are the tolerances allowed on the Capacitors and Resistors?

Is the PIC part number PIC32MX250F128B-I/ML or PIC32MX250F128B-I/SS like I saw in a different thread?

I believe the 3V LDO REG is part number LP5907MFX-3.0/NOPB correct?

Finally any advice on the microSD card slot?

I'm sorry if any of this should be common knowledge but I would hate to go through the effort of building this only to find that I got the wrong component.

Comments

  • biomurphbiomurph Brooklyn, NY
    there are no stupid questions. just smart ass answers!

    we are using standard MLCC X7R caps. Resistors are all 5% tolerance except for the resistor arrays. Those are 1%.
    the PIC is PIC32MX250F128B-50I/SS, but I don't think there's much difference between that and the -I/SS part.
    your 3V reg part number is correct.

    for the SD card slot, please go to the hardware documentation page
    I have updated it, and at the top of the page I link to the part on octopart where you can buy it and gaze into the datasheet.
  • marshmallowmarshmallow
    @biomurph

    I am modifying the designs on DesignSpark. The resistor R5 (1M ohms, connected to pins 62, 63 of ADS1299) when translated to pcb gives a relatively larger footprint of 0402 (with rectangular pads) as compared to the capacitor (e.g. C16 connected in parallel with it) footprint of 0402 (with square pads). I noticed that they have been configured that way in the OpenBCI parts library. But in your pcb design, both capacitor and resistor footprints of 0402 are the exact same (with square pads). What should I implement then? 

    Kindly reply as soon as you see this

    Thanks

Sign In or Register to comment.

© Vanilla Keystone Theme 2026