Wednesday, 19 November 2014

BlueFlyVario_TTL_GPS_v10 released

I am pleased to release the first of the version 10 Bluefly's. Today I have begun shipping back orders for the BlueFlyVario_TTL_GPS_v10. The previous blog post indicated that these were on the way and described the other models under development.

The BlueFlyVario_TTL_GPS_v10 is primarily designed for integration onto the Kobo, although some people will use it with other e-Readers or just for experimenting. See this older blog post for a step by step guide which describes how to install it on the Kobo mini. The procedure is pretty much the same for this updated vario. The simple case described in this earlier post which you can 3d print will still fit, but you will need to drill a small hole for the new button. 

What is in the bag?

Everyone installs their vario in a slightly different way. In the little bag are the following components:
  • The main module. The PCB size is 50mm x 17 mm which is the same as the v9.
  • A small piece of neoprene. This is really important. It must be placed over the pressure sensor if the sensor is exposed to any light (even light through a translucent case). The neoprene allows the air pressure through, but stops the light. Light makes the pressure sensor go crazy.
  • Some clear PVC heat shrink cut to size. It is fine to install the module without a case if you use the heatshink.
    • Poke a small hole through one side of the heatshrink just big enough for the button.
    • Put the neoprene on the pressure sensor, and the heatshrink evenly over the module.
    • Use a heat gun, or a hairdryer on hot setting to carefully shrink the plastic around the module.
  • A 4x1P right angled header. Some people solder the wires directly to the module, others use the header so it is easy to remove for testing. If you use the header I suggest you trim the through-hole pins to the thickness of the PCB so they are flush with the bottom of the board.
  • A 4x1P DuPont connector with 20 cm wires. This will fit in the header, and the wires connect to the serial port of the Kobo. You should trim the wires to be as short as possible so you minimise stray voltages.

New Hardware Features
Since the BlueFlyVario_TTL_GPS_v9 there have been a few hardware changes. Refer to the circuit diagram and PCB layout below.
  • Button. This is the biggest change with the v10 BlueFly's. The button provides soft power on/off by controlling the shutdown pin of the TC1015 voltage regulator. When pressed the shutdown pin of the regulator is connected to the supply voltage via the diode, which turns on the regulator and powers the micro-controller. One of the first things the micro-controller does is keep the shutdown pin of the regulator turned on. The small diode in conjunction with the 10k pull down resistor then allows another pin on the micro-controller to sense button presses. The behaviour of the button is programmed like this:
    • When the module is off, a short press will provide soft power-on as described above. The module will do the start up beep thing.
    • When on, short presses will turn the audio on an off. A short beep provides confirmation.
    • When on, a long press (2 sec) will power the module off.
  • Solder Jumper. Some people will want the module to power on as soon as power is supplied to the module (that was the behaviour of the v9). By closing the solder jumper with a dab of solder the shutdown pin is permanently biased to the supply voltage. You can still use the short presses on the button to turn the audio on/off. A long press will turn the module off, then it restarts in six seconds.
  • Thinner PCB with gold contacts. I changed to a thinner 4-layer PCB to optimise component placement. ENIG contacts provide a cleaner finish.
  • Additional capacitance on power. I added an additional 1uF capacitor to the supply voltage line. This will reduce stray voltages in the supply if you have longer wires, which should improve GPS performance, but I still recommend trimming your wires as short as possible.
  • UART TLL resistors. The resistors in series with the Tx and Rx lines on prevent the module being powered on by stray voltage. I selected 2.2k based on trial and error. These values work with the Kobo and with FTDI based USB to serial converters.
  • Exposed U1 pins under the GPS. The second serial port on the microcontroller is connected directly to the PA6H GPS. If you are a super electronics hacker and want to update the firmware on the GPS then you can use this serial port for a temporary connection.
  • Exposed speaker pins. Some people want to wire in a different speaker. The pins in parallel to the speaker make this a little easier.

New Firmware Features

There have been a bunch of changes to the firmware to accommodate the new hardware and incorporate some new features. Some key changes:
  • The firmware now includes a modified version of the ds30loader bootloader. This will allow future firmware updates if you connect the module to a PC using a USB to TTL serial converter. The bootloader mode is entered by powering on the module with programming pads 2 and 5 shorted together. I will produce a more fulsome description of the firmware upgrade procedure in later posts.
  • There is now an auto power off feature. Essentially, if the module has not moved more than a certain number of meters vertically for a set duration then it will power down. The default settings are 2 m (20 dm) vertical movement in 10 minutes. You can adjust these settings like other hardware settings. I will update the hardware settings manual and BFV Desktop app at some stage.
Next Steps

I am working on release of the Bluetooth_v10 and the USB_v10 over the coming weeks, in conjunction with catching up on back orders and trying to keep on top of the rest of my life. Please be a little patient if you are waiting on a back order.


  1. Great developments!! I'm looking for such a device for quite some time now. And I would also like to assemble my own vario myself.
    Is there a plan to include the GPS to the bluetooth version? I would also prefer a bluetooth low energy chip in stead of the RN42 (how about RN4020?)

    1. You can connect a serial TTL GPS into the exposed U1 port, but the physical layout is a bit messy. I am looking at a combined BT LE and BT SPP module for a future version. Moving away from BT SPP would mean that many apps and platforms are no longer compatible.

    2. I'm looking for a GPS/vario/BT solution as well to combine with a Kobo with integrated BT. (Presently used with Wintec BT GPS but lacking the vario)

      Which serial GPS would you recommend? Same FGPMMOPA6H as use in GPS/TTL version?

      Is there a thread/blog that shows some basic steps to connect/configure the serial GPS?

    3. Frank, The BlueFlyVario currently has three models (Bluetooth, TTL_GPS and USB). Only the TTL_GPS has an onboard GPS, the other two expose the second UART port and it is possible to hack on a GPS if you have the skills. I would recommend the PA6H as I know it works. See some of my other blog posts for a detailed description of the features of the other models.

    4. Al, Thanks for promt reply. Skills and tools are present.
      You mentioned just to connect PA6H to U1 port. Is it necessary or recommended to connect PA6H pin NRESET to PIC pin RA2 as well?

    5. Frank, On the Bluetooth model RA2 is connected to the reset pin of the RN42 bluetooth module instead of the GPS NRESET pin. The Bluetooth firmware uses the pin to control the module, however the TTL_GPS firmware just holds RA2 high to keep the GPS enabled. In a future firmware update I might change that, although can not think why I might need to at the moment.

  2. Al,
    Do you know what the power consumption is?
    Also what is your view on connecting v-backup to the 3v3 rail with an 8-10k resistor?

  3. Hi Al,
    I bought from you 2 BlueFlyVario TTL version 10,
    I can not connect with the PC (windows 7, java latest version) via the serial port, I tested with serial / TTL interface directly to the COM port on the PC, I tried with USB / TTL adapter. BFV connect to port TTL (positive to positive, gnd with gnd, tx with tx, rx with rx), turn BFV and open BFVDesktop, set the correct COM port in the drop-down menu, and I try to connect, nothing happens, I also tried to change the Com port, to reverse the data lines (tx with rx and rx with tx) but nothing happens.

    Can you help me?

    Before trying to do a firmware upgrade I'd like to connect with BFVDesktop so be sure of optimum connection.


    (sorry for my english, translated with google)

    1. Please confirm that the BlueFly is powering on when you press its button. You should hear the normal start up beeps and the green light come on momentarily. Also can you confirm that the USB/TTL adapter you have is working with other TTL devices other than the BlueFly.

  4. I confirm that the BFV is properly powered (3.3V)
    I confirm that the BFV lights up regularly when you press the button.

    I have no other TTL devices but I have three different adapters USB / TTL and everyone is the same.

    Can you show me the correct procedure step by step?

    1. I could hear a short and a long beep when I try to connect ...
      but in BFVDesktop no values appear.

    2. It is good that power is working properly. What is the model of your USB/TTL adapter?
      The correct procedure to connect a BlueFlyVario_TTL_GPS_v10 to the BFV Desktop application on a windows computer should be:
      1. Ensure you have the latest version of Java installed.
      2. Get the latest version of the BFVDesktop application from the support page. Unzip the folder somewhere before running the application.
      3. Plug in your USB/TTL adapter and ensure that the correct serial drivers for it are installed. This will depend on what chip is used in the USB/TTL adapter. I mostly use adapters with FTDI chips because I am very confident in their drivers.
      4. Determine what serial port is assigned to the USB/TTL adapter by windows. Depending on the model of the adapter (chip/driver combination) you might have to adjust some settings to get the serial port working properly. The default settings of FTDI based chips work.
      5. Connect the BlueFly -> USB adapter by connecting VCC->VCC, GND->GND, Tx->Rx and Rx->Tx.
      6. Test that the BlueFly is correctly getting power by powering it on and off. You should hear audio beeps and the green led (and blue led) should light.
      7. Open the BFVDesktop application and connect to the serial port you installed.
      8. Power on the BlueFly, you should see the data stream.

      A couple of tips:
      - You can adjust the baud rate (default 56000) in the BFVDesktop application. Other serial settings are adjusted in
      - If you do not see the data either the serial port is not installed properly, the TTL connection is not made properly (check Tx->Rx connections, and check continuity from the adapter all the way to the micro controller), or there is a problem with the BlueFly.

  5. Thanks Al,
    write what I did, probably my USB / TTL interface that does not work well.
    Can you tell me which interface USB / TTL should I buy ??

    1. I use devices which use the FTDI chips. The last one I purchased was this one from ebay:

      This one from Sparkfun should operate in a similar manner.

  6. Hi Al,
    Did you try using GPS/GLONASS chips? This may be the way forward.

  7. This comment has been removed by the author.

  8. Hi Al, I am using your excellent TTL v10 , but I need to attach some external speaker. I want to use JP1and JP3 connectors. Please, can you recommend some speaker? Or can you send me some parameters, which should be meet with the second speaker?Should be 8ohm ? Have youtested with some specific one? Thank you very much for your work as well as your responce :-)
    Have a nice day

    1. Jan, I just published this blog post to answer your question:

  9. You said "The neoprene allows the air pressure through".
    Wouldn't it the glue stop air circulating through the pressure sensor ?
    I am little scared about that.
    please confirm.

    1. Yes, the glue would stop the pressure sensor working. You should use the black squishy side of the neoprene to touch the sensor - do not remove the white tape. The neoprene is held on the BlueFly by the heat shrink. See for example pictures of the neoprene.

  10. HI,
    Is Kobo Touch suitable for your device?
    And installation similar as in Glo and Mini case?

    1. Yes, the Kobo Touch works, provided it is a version of the Touch which has an internal serial port. I think there may be some versions of the Touch without a port. Search the xcsoar forums, the topic has been discussed on there a few times.

  11. Dear. Bluefly team.

    I ask one Question.

    this model include plastic out case? on kobo.

    or it make my self?


    1. This model vario does not include a plastic case. You would have to make one yourself, although many people do not use it. See this blog post for information about using the vario without a case.

    2. thank you for your help ;)

  12. Hello! What is the maximum cable length can be from a GPS sensor to Kobo tablet? I need to make a sensor on the visor panel and airframe tablet built into the dashboard.

    1. I am not sure, it depends on many factors such as the amount of electrical noise, shielding, etc. TTL UART connections are not designed to be long, but for other designs I have stretched them up to 10 m. I suggest you run some tests.

  13. hola soy de españa y estoy interesado en fabricar mi propio kobo con gps y vario. seria usted tan amable de enviarme el pcb a mi correo o indicarme como puedo conseguirlo? gracias de antemano.

    1. Antonio, Please visit this page if you wish to purchase a vario.

  14. disculpe si este no es el hilo correcto para este comentario pero no se como puedo dirigirme a usted.

  15. This comment has been removed by a blog administrator.

  16. Hello Al,
    I just received my Blue Fly TTL and connected a battery to V+ & ground to test it and it is working GREAT so far! AWESOME.

    Can I connect BFV TTL to a separate battery (common ground with Kobo) and connect the Tx & Rx to the Kobo in order to save the weak Kobo Battery?

    1. Yes, that will work. Make sure to respect the voltage limits of the regulator. You will need 3.2V min and 6V max.

  17. Hi Al, I've just flown 1600 kilometres in four flights with your Bluefly TTL. My Kobo Mini with XCsoar worked perfectly on a kneeboard. I used some external power just in case, but I think the setup would have gone the full 6 hours of my longest flight. (I didn't use the vario as the glider has a good total energy setup.) Thanks for a great design.

  18. utilizzando un cavo USB e modulo di convertitore dell'adattatore RS232 posso usare BlueFlyVario_TTL_GPS_v10 montato su un tablet ?

  19. utilizzando un cavo USB e modulo di convertitore dell'adattatore RS232 posso usare BlueFlyVario_TTL_GPS_v10 montato su un tablet ?

  20. using a USB cable and adapter module RS232 converter I can use BlueFlyVario_TTL_GPS_v10 mounted on a tablet?

  21. Hi, friend! I am interested in buying the BlueFlyVario_TTL_GPS_v10, for installing in a Kobo mini. Do you have it ready for shipping?
    Do you know how long would it take to get to Brazil? Thanks!

    1. Thanks for your order Eduardo - Brazil post can take a while, but it always seems to arrive eventually.

    2. I'm buying one today Eduardo, let's see how long it takes. I have the impression that import taxes will be charged on tupinikins land!

  22. Hi Al,

    thanks for putting all the efforts into developing this nice Vario/GPS.
    I am looking for a solution to combine a Vario /GPS with a Kobo Glo. I found your device. I would like to connect the TTL version with the Kobo. But since I am just starting flying, I also would like to have a simple Vario (without the Kobo) just to practice thermal flight. Since I don't trust bluetooth connections much, I would like to use the TTL wired solution.

    Long story short: Is it possible to use the TTL version solo without the Kobo (with a battary pack) for just have a simple beep vario?

    Have you experience with a Kobo Glo and installing a Bluetooth device (maybe BTM400_6B HC-05) and connect the BlueFly Bluetooth Vario with GPS Shield to it?

    Thanks a lot!

  23. hello,
    is it possible to connect VarioGPSTTL to a simple tablet android (less gps) on the port usb of tablet.
    What converter ftdi can i use for this ? and what parameter in XCSOAR or XCTRACK ?
    Great thanks for your response

    1. I am sorry, there is no easy way to do this with the drivers in xcsoar.

  24. Hello Al,
    A month ago I bought BlueFlyVario_TTL_GPS_v10. At last I had to order the Kobo GLO and I began to assemble my flycomputer.
    Hardy assembly has passed without any problems, installation XCSOAR too, but there was a problem with the configuration.
    When the flycomputer works, no GPS. the words "expect signal" is displayed permanently. I tried to select different options for the driver, as described in the manual, but it still does not work. This information is fed to a bluefly book.
    Searching solution I found out that it is necessary to update the firmware of my BlueFlyVario. I prepared USB-TTL adapter, driver download, and tried to renew. Unfortunately I did not succeed. I took advantage of the proposed DS30LOADER utility, but it does not work. I tried to use the utilities REALTERM and Dektop BFD to check the connection, but found that the information is not supplied to the PC.
    Wires connect I checked, the correct contact​​​​​​​​​​​​​​​​s, too. In order to make sure that it does not work, I tried to buy another converter. Now I have 2! One-on-chip PLX230HX, the other on the CP2102 chip.
    Please tell me what could be the problem. How to fix it? I tried to find the answer to the forms, but it seems no one is faced with such a problem.

    More information in photos:

    1. Hi Simon,

      Thanks for your detailed explanation and for the photos. It looks like from the photo that the Rx on the PLX230HX is connected to the Rx on BlueFly. You need to connect Rx (PL) to Tx (BlueFly), and Tx (PL) to Rx (BlueFly).

      However, why do you need to update the firmware? There has not been a firmware update for a few months and I imagine you already have the latest firmware.

    2. Greetings
      The fact that I can not make friends Kobo Glo and GPS sensor. When you turn XCSoar I constantly see the message "waiting for GPS signal". I tried to install different versions XCSoar, but the result did not change. I tried it indoors and outdoors, but without success.
      Data received from the sensor on the book (it is seen from photos above), but for some reason can not be understood by Kobo.
      On one of the forums I found a description of a similar problem, and the solution that leads there - firmware update.
      By this I wanted to try to upgrade.

    3. The pictures indicate that you are getting sentences from the GPS through the Bluefly, and then sent to the Kobo. However, it sounds like you are not getting a fix. Please record a NMEA log and send it to me via email.

    4. Hello!
      I tried to change the wires on your advice, using СP2102 chip and was finally able to establish normal contact PC-BlueFly.I think that connection via TTL-ГЫИ is heavily dependent on the manufacturer and model of the adapter chip. How do I find the current firmware version on BluFly?

    5. To check the fimrware version just restart the vario and see the information coming from it. When you press and hold the button you will get:


      If you press it again then it will restart with:

      BFV 10 208
      SET 0 100 20 1 0 1 180 1000 100 400 100 40 5 30 100 1000 0 1 21325 207 1 0 1 34 20 600 0 40 100
      MS5611 2148 48265 49515 30132 27266 31214 28587 25525

      The first few lines are the firmware version (, and the lines starting with BST and SET indicate all of the settings.

    6. Hi Al,
      I managed to solve the problem with my BLUEFLY.
      The problem was not related to the firmware. This is XCSoar configuration problem.
      I put on the transfer protokol LK data. In XCSOAR configure the following:

      Port: ttymxc0
      Baud rate: 57600
      Bulk baud rate: 9600
      Driver: LXNAV
      Passthrough device: On
      Second driver: LXNAV
      Sync. from device: On
      Sync. to device: On

      GPS is stable, the next stage of flight tests!

    7. Great. Thanks for letting us know.

  25. Hi Al.

    I just install the bluefly vario gps 10 on my kobo glo hd.
    the kobo is not starting when I connected the bluefly tx to the kobo rx.

    but it is ok if I am starting the kobo and then connect the kobo rx cable.

    do you know if there is another way to hack that ?


    1. See the note on the v11 page about the pull up resistor:

  26. Hi Al,

    I am trying to short the JP1 on the board so that it automatically turns on. However, when this is shorted the vario goes crazy. When I remove the solder short it goes back to normal. Am I doing something wrong?

    1. It is difficult to know what might be wrong without some data. Please email me a photo of your setup, and a nmea log showing the data from the BlueFly.