The Pyxida system uses Xbee radios to communicate. The newest version of the software will use the Xbee's built in API mode in order to efficiently construct and verify packets sent from the ground station to the rocket and vice versa. 

Configuring the Xbee for API mode

First, download the Xbee configuration tool XCTU (https://www.digi.com/products/xbee-rf-solutions/xctu-software/xctu). Using a breakout board, connect one of your Xbee's to your computer by USB and connect to it via XCTU. Select the Xbee you just connected to and open the radio configuration page.

There are several settings you need to change:

• Change AP to 2 (API enabled w/ PPP)
• Change ID to a predetermined value (shown here as 117). This needs to be the same on both Xbees.
• Change DH to 0
• For DL and MY, set these values so that DL for one Xbee is the MY for the other (i.e. the destination for one of the Xbees is the address of the other). Do the same for the other Xbee, but with a different number.