cys

The homebrew_mini2 board is now a shared project at Osh Park. You can build your own HB_mini2 by ordering the board, here.

The parts list is as follows:

   z1/z2/z3 TVS diode 12vwm 250vc 0402 F2862CT-ND

   CONN USB MICRO B RECPT SMT R/A 609-4613-1-ND

   C7 CAP TANT 10UF 10V 20% 0603 718-1673-1-ND

   CONN IC SOCKET 24 POS DIP 30AU A35058-ND

   F1 PTC RESETTABLE 6V, .500A SMD 0805 F2772CT-ND

   Y1 CRYSTAL 25MHZ 18PF SMD 535-9128-1-ND

   IC1 IC REG LDO 5V .8A 8SOIC MC33269D-5.0GOS- ND

   IC2 IC REG LDO 3.3V 0.5A TSOT23-5 576-1910-1-ND

   ICU IC MCU 32BIT 1MB FLASH 64LQFP 497-11767-ND

   SWITCH TACTILE SPST-NO 0.05A 12V SW1104CT- ND

   7 x C 100n 0402

   3 x C 2u2 0402

   2 x C 18 pF 0402

   1 x C 1 uF 0402

   2 x R 40K 0402

   2 x R 22R 0402

Another thread that could be helpful can be found by following this link, here.

Below is the schematic for my homebrew mini2 in case anyone finds it useful. My design criteria were: I) incorporation of an STM32Fx chip to allow usage of the netduino 2/netduino plus 2 firmware, and II) all pins compatible with my dive computer/rebreather controller project pcb & associated parts developed with the netduino mini. Through the iterations I've had to solve a USB cable grounding issue and shuffle pins around several times to get backwards compatibility. The last iteration I left pins 2, 3 and 22 disconnected because I had everything I needed elsewhere and wanted to save a little time routing. I just finished chasing down a side effect bug with my 24 bit ADC. The HB mini2 v1.10 has been robust so far, and both the HB mini2 and the netduino mini are now interchangeable on my project pcb. 

homebrew_mini2 by cys1, on Flickr

As regards oled screens, there are lots of sources (eg digikey, mouser, newark, newhaven, sparkfun, adafruit, etc...).

Is it possible for you to point me to where to look for parts, e.g. pressure/temperature sensor and oled screen?

Additionally, you seem to have a very well made casing for the electronic parts. Do you have to expose the sensor to have contact with water? If you do, how was it accomplished to prevent water from getting in due to high pressure at depth? Sorry to bomb you with all the newbie questions.

I just happened to see recently that Sparkfun now offers an MS5803 pressure/temperature breakout. I use this sensor, but I made my own breakout board for it. There is a conversation about the breakout board on the bottom of the Sparkfun page that provides a link to schematics for sealing the sensor with an oring.