Re: [Paparazzi-devel] apogee board 2.0 - feature questions

[Michel GORRAZ]

Hello Jan

- IMU will be updated with MPU9250. This will eliminate need for an
  external magnetometer

Apogee v1.00 is MPU9150 compliant (it includes a _crappy_ mag) but using a MPU9250 is a good idea.

If possible, put the 9250 as far as possible from the switching power supply.

 

- SD card sold is discontinued, and will be replaced by the one
  currently in production by molex

New Molex ref is 503182-1853 (exact replacement of 503182-0853)

 

- mounting holes - we find the 1.8mm holes pretty difficult for
  mounting the board. The holes will be changed to 2.5mm

v1.00 holes are 2mm, if you really want to increase the diameter, use 3mm, easier to find than 2.5mm

 

- servo connectors - we would like to turn the 3 pin connectors 180
  degrees, so that pin 1 corresponds with servos signal. This will make
  the board consistent with the standard molex 1.25->futaba/JR harness
  cables
  (http://hobbyking.com/hobbyking/store/__46385__Male_Molex_1_25_to_Female_JR_Servo_Extension_1pc_EU_Warehouse_.html?strSearch=molex%201.25)

For some historical reasons, GND is always on pin 1 of all connectors, so doing this you will be hobbyking compliant but not pprz anymore (hello magic smoke)

You better buy a tool to swap the hobbyking's harness molex pins :
http://www.digikey.com/product-detail/en/0011030043/WM9937-ND/252489

 

- power connector - we find the power connection to the board a bit
  difficult without a proper connector. The 4mm connectors (the distance
  between the 2 pads) are rather too big for such a tiny board. We will
  place a 4 pin 1.25mm molex blade header - pins 1,2 as Vdd+, and pins
  3,4 as GND. This will still leave the option to solder wires directly
  to the board.

Don't forget the current of the entire aircraft (servos, modem, GPS...,) will go through your tiny 1.25mm Molex (0.8A max with 32AWG cable)...

Good luck for routing ;-)

Regards

Michel