The Eggfinder can be a very effective tool for locating your rocket - GPS coordinates transmitted to your handheld receiver works great. Some folks also have experience with capturing the GPS data via Bluetooth for post flight analysis. Cris @ Eggtimer Rocketry has thoughtfully designed the Eggfinder TX in such a way that it can also be interfaced with a data logging module like OpenLog, which writes data to an on-board micro SD memory card. When I first started playing with the OpenLog module, it simply worked; no coding or special configuration was required. I was impressed with the small footprint. My first mock-ups included a piggy back board with some short leads connecting to the TX serial connectors. It then occurred to me that a custom PCB could be mounted on the TX doing away with the wires completely. In a nutshell, through trial and error I came up with a simple adapter board that mounts an OpenLog module directly on an Eggfinder TX. I had some boards made, and they seem to work well. I have all that I need, and thought that other Eggfinder owners might also like an easy option to capture GPS data during the flight, while also transmitting the data to their receiver. (Important note: This only works with the current B6/B7 version of the Eggfinder TX. This isn’t designed for earlier versions.) You can import the flight data into Google Earth, manually look at timestamps to correlate events, etc. Sound Interesting? Effective July 2017, these are now available from Eggtimer Rocketry. See post #54 for additional details.