Friday, 24 January 2014

BlueFlyVario_TTL and other news

Despite the paucity of posts there is still a lot going on in my BlueFlyVario development world. I have recently return home after spending time away with family and have only just got on top of the back orders. I discovered it is possible to make and ship over 30 varios in one day! That brings the total number of version 7 prototypes shipped to over 125 since release just over two months ago.


In addition to the dual sensor version I mentioned in my last post (which I am still working on) I am in the final stages of testing a much simpler little device. I am calling this the BlueFlyVario_TTL. It is essentially just a BlueFlyVairo without the expensive RN42 Bluetooth module and battery management. I expose the TTL serial Rx and Tx which would normally go to the RN42. This allows the same hardware settings to be altered. Essentially this will provide a tiny super sensitive audio only vario which can be integrated into stuff. The current BlueFlyVario_TTL prototype is pictured next to the version 7 prototype below. It is about 35mm x 12 mm x 6 mm.

In the configuration above the BlueFlyVario_TTL does not have a case, battery, switch or battery charger. I will ship it encased in heat shrink. If power (3V) is applied to the outer pins it turns on. I envisage that the BlueFlyVario_TTL will be integrated into helmets with users providing an appropriate wiring, switch and power supply. I think that the widely available and cheap 18650 battery with a holder and switch is probably a good choice. Also, with the header pins shown above the BlueFlyVario_TTL can be plugged into a USB to serial converter for programming via a PC (or even to integrate with XCSoar or other programs via a cable). I have included a couple of holes for connection to helmet speaker systems if users want to disable the on-board speaker (by clearing the solder jumper).

I have not quite settled on the final configuration for this device. I might include a little serial programmer, or a switch, or a battery, etc. I am not quite sure. In the configuration shown above it will cost between $50 and $60, but if I start adding additional bits it would cost more. If you are interested in the BlueFlyVario_TTL please contact me and let me know your preferred configuration. Before release I will also need to write a PC app for setting hardware parameters via serial ports and document the serial protocol.

Speaker Changes

My supplier for the on board speaker discontinued the black colored speaker I used on the first version 7 prototypes. I spent some time testing a wide range of other speakers and finally settled on the white Kingsgate one pictured above. It is just as loud as the previous one and only a few cents more expensive per device. I hope this one stays available for longer.

App Update

I have recently fixed a bug with the Android app. This fixes a problem that European users had with altering hardware settings containing decimal points. 


  1. Are you considering make BFV app opensource? This should make it get all the features other soft has and much more competetive with other software.

  2. The app is open source, released under GPL. See:

  3. yep. stupid me... skiped that part in my education: "ask at least google first , before asking oher stupid questions..." :D