Saturday, 25 October 2014

Version 10 BlueFlys

In the next six weeks I expect to release the version 10 range of BlueFlyVarios. The range will consist of three models:
  • BlueFlyVario_Bluetooth_v10. This model represents the evolution of the original BlueFlyVario which started a few years ago. It is designed for Android users who want to use a vario app on their phone. However, it is also popular as a stand alone vario.  
  • BlueFlyVario_TTL_GPS_v10. Used with the Kobo (or other eReaders) running XCSoar. 
  • BlueFlyVario_USB_v10. A new model. Designed to provide a minimalist audio vario.
They all share a few new features; updated firmware, user update-able firmware, a new button design, and improved PCB quality. Some of the things you have come to expect from the BlueFly will just be the same: super sensitive vario, low cost, very hackable, great support, and open designs. See the table below for a detailed list of technical specifications.

Technical Specifications

Planned release
November 2014
(Replaces BlueFlyVario_Bluetooth_v9)
November 2014
(Replaces BlueFlyVario_TTL_GPS_v9)
December 2014
(New device)
What is it designed for?
Interfacing with Android free flight applications (BlueFlyVario app, XCSoar, other apps).
Using as a standalone audio vario when not connected via Bluetooth.
Interfacing with the Kobo running XCSoar (or other eReaders).
Using as a minimalist standalone audio vario.
Primary Data Interface
(UART 2)
RN42 Bluetooth module using the Serial Port Protocol. Simple interface to most devices supporting Bluetooth SPP (not iOS).
3.0V TTL interface via headers on the module.
On board FTDI FT230X USB-to-Serial converter. Appears as a serial port on PC. Can be interfaced to Android OTG devices.
Secondary Data Interface
(UART 1)
Exposed for hacking.
Onboard PA6H GPS. Data is multiplexed with pressure data.
Exposed for hacking.
Hardware Setting Procedure
BlueFlyVario Android App.

BFVDesktop application on PC’s with Bluetooth adapters.
Telnet into Kobo (when installed).

BFVDesktop application with a USB to Serial converter.
BFVDesktop application.
Board and battery protected by heatshrink.

Acrylic prototype case included.

3D printable enclosed case design to be distributed.
Board protected by heatshrink.

3D printable enclosed case design to be distributed.
Board and battery protected by heatshrink.
Physical dimensions
With included acrylic prototype case. 53 x 34 x 18 mm --- 41 g
The module in heatshrink.
50 x 17 x 9 mm --- 10 g
The module with battery in heatshrink.
50 x 14 x 12 mm -- 12 g
Power Supply
Included 600mAh LiPo battery charged via micro USB adapter (no data connection).

Lasts more than 10 hours with bluetooth and audio running.
Powered from TTL header.
Included 200 to 300 mAh LiPo battery charged via USB.

Expected life greater than 10 hours.
Hardware Button
Long press for soft power on/off. Short press for audio on/off.
Will be upgradeable via ds30loader.
Pleasant sounding 95dBA electromagnetic transducer.
Other audio outputs hacks possible using exposed headers.
Available Hardware Settings
Similar to BlueFlyVario version 9 devices, with some extra settings.
Pressure Sensor
MS5611 accurate to 10cm updated at 50Hz.


A few months ago I planned these next versions to be ready based on the expected demand of the version 9 range. However, they once again proved to be more popular than planned and there are no more of the version 9 models available. I am waiting on a few parts to complete the first batch of the version 10 models. If you order the Bluetooth or TTL_GPS version 9 model in the next few weeks consider it a pre-order for the version 10.

Friday, 3 October 2014

BlueFlyVario_Bluetooth_v9 Released

I have been shipping the BlueFlyVario_Bluetooth_v9 for a while but did not get a chance to blog about it. This is only a minor update to Version 8. A summary of the important changes from earlier versions is listed below:

Hardware Changes
  • I have added a small battery connector (Molex 1.25 mm) instead of soldering the battery to the board. The wires now wrap around the edge of a board in a small milled slot. This makes assembly a bit quicker and will allow users to change batteries without soldering.
Firmware Changes
  • The firmware now has a minor and major version. The $VER* command now responds with '$BFV MAJOR MINOR*'. The firmware version is currently 9.4.
  • I have included a bootloader. It is a slightly modified version of the ds30loader. At some stage I will blog about how to use the bootloader to update the firmware from a pc.
The circuit diagram and PCB layout for this release are shown below:

The way ahead

I am planning the version 10 hardware lineup with three models based on the primary external interface. These will probably incorporate a button instead of a slide switch. They are some months away I think.:

  • A Bluetooth model with battery similar to this model - designed for integration with Android devices. 
  • A TTL with GPS modules - designed for integration with devices such as the Kobo. 
  • A new USB model with battery - designed for stand alone use. 

Friday, 5 September 2014

Magazine Reviews

A few reviews of the BlueFly varios have been published in the last few weeks. I can't publish the full reviews on the blog, you will have to subscribe to the magazines for that. I have been really impressed that the reviews are full of relevant facts and very positive.

The first review was by Sascha Burkhardt in the August 2014 edition of Thermik, a German language paragliding magazine. Google Translate allowed me to understand just enough of the German; like many Australians I barely speak English.

Next, just a few weeks later, came a review by Richard Sheppard in the digital edition 155 of Cross Country. I think the paper version will be out in the next few days. He reviewed both the bluetooth and ttl versions.

A few other reviewers also have plans to publish articles. All this press means I have been super busy answering questions and shipping varios. I started shipping version 9 of the Bluetooth model a few weeks ago, I should get a chance to blog about it in the next week...

Sunday, 20 July 2014

1000 BlueFlyVarios

We now have over 1000 BlueFly Varios in the hands of paragliding, hang gliding and sailplane pilots around the world! This milestone was passed a few weeks ago. I was pretty excited and let a few friends know; but only now do I get to blog about it. In this post I am going to reflect a little on what the BlueFly project has achieved, where it is at, and what I am planning for the future.


Have a look back at this early blog post from 2011. I have pretty much did what I said I was going to do. Notice I mentioned 10 prototypes, in a later blog post I mentioned 50. I never thought that we would make over 1000, nor did I think early on that could just be the start.

The chart below shows how production has continued to increase. This chart starts in May 2013 when the version 6 prototype was released. That was the first one with an onboard audio speaker which proved to be something that pilots really wanted. Notice the rapid increase around the start of the European flying season, then again when the device to integrate with the Kobo was released. It does not include every vario produced, only those ordered over the internet. Quite a few have also been sold directly to pilots in Australia. It was early July when the 1000 milestone was passed and there is no sign that interest is slowing.

Another achievement has been the ability to share pretty much everything. This is 64th blog post, the Facebook page helps pilots collaborate, GitHub allows the Android code to be shared, and more recently I have uploaded 3d printable case designs to Thingverse (as I am writing this the 3d printer is whirring in the background on a new case design). I intend to continue to share the designs as the BlueFly adventure continues.

All of those achievements are really about me, but the thing I am most happy about are some of the great flights that pilots of all experience have reported. Some of the world's top pilots are regularly doing awesome flights with the vario. I got a kick out of the vario helping in the 2013 X-Alps, and more than one top pilot will be using it in the next one. However, some of the best stories come from new pilots. Most of us can remember that first great flight with the help of a vario. For some BlueFly users their first flight using a vario is with one of my little devices that beep, and the stories of smiling faces are an awesome source of motivation.

What is the current status of the project?

Perhaps the biggest news is that I have had to start a company in Australia to manage this hobby. There are a lot of things to do to keep up with the current rate of production and many payments to make. So to manage the tax affairs properly a company was the obvious choice. The project was never about making money, and it still isn't, but unless I group up all of the activities in a company then I could get myself in trouble. Operating as a company in Australia also means I separate it from my personal affairs.

I am currently focusing on production of the Bluetooth and the TTL_GPS prototypes. I recently shipped the last of the BlueFlyVario_TTL version 8. There was some interest, but most pilots wanted to integrate that older version onto their Kobo and the TTL_GPS is more suitable for that.

With increasing orders I want more time to do development instead of the simple assembly work.  A fabrication house in China is now doing some of the component assembly. They are the same guys used for PCB manufacture for some time, and now they are soldering on many of the components as well. It does not add much to the cost (they can source some parts cheaper), and their soldering quality is better than can be done by hand at home. I soldered every component for over 900 of the first 1000 varios in my little home workshop. In hindsight, I should have got this assembly done earlier, but I did learn a lot and the vario design got better because I was assembling it. I am still planning to program and test each one.

The future

There are many plans for future devices which perform better, are easier for non technical people to use, and offer additional features. I have listed below some of the of the things I am working on when I get time. It is unlikely that they will all end up in a future device, but I am sure you will see some of these things plus some additional surprises.

  • I am still planning to continue the development for the airspeed sensor using a pitot tube. I have not developed this much since the last blog post about it.  
  • I would like to offer an onboard memory and flight logging capability. Other than just going beep I think many pilots really want their device to log their flights. I think this should be possible with a microSD card. I would probably change the processor if I went down this path. 
  • User update-able firmware would allow me to roll out little tweaks. This means a bootloader needs to be developed. I am testing a few of them. 
  • Soft power on and off will allow the use of a tact switch. That should be more reliable than the current slide switch. 
  • I intend to change the battery connector on future versions to a Molex connector. That should save a little time in assembly and make it easier for exchanging the battery. 

I think the future is looking pretty good for home-brew flight instruments. I don't think you will see the end of the BlueFly project for a while yet.

Sunday, 6 July 2014

BlueFlyVario_TTL_GPS Simple Case

Minimalist Install

Over the last few weeks I have shipped more than 100 BlueFlyVario's with GPS for installation on the Kobo Mini. I have shared a few of the install photos on the BlueFlyVario facebook page. If you have pictures and you want to share please let me know.

I have also refined my preferred install method. Instead of using the Dupont connector I prefer to wire the module directly to the Kobo. All of the steps I have previously blogged about still apply. This really just changes Step 4 in that process.

I start by placing the BlueFlyVario_TTL_GPS module on the front bezel of the kobo in the bottom right. Placement is pretty important, the holes in the board need to be in just the right position. In the image below you can see the bottom right corner of the module is just where the Kobo case starts to curve. The holes are about in the middle of the right bezel, and the bottom of the module is flush with the bottom of the Kobo.

After marking the hole locations I drill five 1.5mm holes from the front of the case (very carefully). Take care to avoid the plastic bits getting stuck in the Kobo. Five wires are soldered on to the module from the bottom and passed through the holes. If you plan to wire in VBACKUP for the GPS then make sure that wire is long enough to reach the test point near the positive terminal of the Kobo battery.

Simple Case

If you have left the heat shrink on, the module should work just fine if you glue it to the front of the bezel. However, some people wanted a more robust case so I designed a basic one in solidworks which is suitable for 3d printing.

I have uploaded the design to Thingverse where you can download the STL file and use the 3d viewer to visualize the part. I printed this using blue PLA with a 0.35mm nozzle and 0.2mm layer height. The screws are M3 x 6mm countersunk with M3 Hexagon nuts. I place the case on top of the GPS on the bezel to mark the screw holes then drill with a 3mm bit. The hexagon nuts fit neatly in the inner part of the Kobo with a little plastic removal around the USB connector.

The final install is shown below. You can't see that the little piece of neoprene is still on the pressure sensor. It is important and you should not forget it. The case has a few internal parts to hold that neoprene in place.

I think it feels best when the XCSoar display is reverse portrait. The LED's are visible through the case. If you are a 3d printer person you will be a little critical of how well my first layer height is tuned. I will get better for future prints...

Friday, 20 June 2014

Backorders Shipped

For the first time in over eight weeks I have all backorders ready for shipping first thing on Monday morning. It took way too long to wait for components. Since they all arrived on Thursday and Friday I have been working non stop to make about 100 varios and they are all now tested and packaged up. The post will probably take two to three weeks for most European destinations. If you ordered and did not get a shipping notification email please let me know.

TTL_GPS_v9 (rev 2)

After selling out of the first batch quickly I have got a new batch of PCBs for the BlueFlyVario_TTL_GPS_v9. The rev 2 board has a few minor changes:

  • I removed the pcb pads for the switch. 
  • It is now about 1mm less wide. This makes it fit more neatly on the Kobo bezel. 
  • I have exposed the VBACKUP pin of the GPS next to the V+ pin of the TTL connection. If you attach this to a power supply (like the battery in the Kobo) the GPS will get a fix much quicker between power cycles. It consumes very little power. See the PA6H datasheet for more information. 
See below for updated schmatics and pcb layout:

New Sleep Command

The sleep command included in the first v9 firmware ($SLP*) allows the BlueFlyVario to be woken up just by sending a character over the serial port. In rev 2 I added a command $SLX*. This puts the BlueFlyVario fully to sleep, it can then only be waked with a power cycle.  

Kobo Nickel Patch

This is for advanced users. I am sure there is a better way to do it but I am not sure how. To make these changes you can telnet in to your Kobo via Putty and edit files using vi. I posted most of this to the XCSoar dev forum but have yet to commit the changes. Once again, many of these ideas come from my power user friend Steve.

During the ongoing development of the BlueFly vario I have found it might be useful to run some additional commands when switching from the KoboMenu to Nickel. I have used it to send the new sleep command to the connected BlueFly vario so it does not consume power when using Nickel. The sole patch for XCSoar is to include this in /kobo/rcS [Update: The file path is actually /opt/xcsoar/bin/rcS]

# launch user script before nickel start
if [ -f /mnt/onboard/XCSoarData/kobo/ ]; then
source /mnt/onboard/XCSoarData/kobo/

just just prior to the call to unmount the xcsoar files and launch the original nickel rcS:

umount -l /mnt/onboard
exec /etc/init.d/rcS

My has one command:

sh /mnt/onboad/XCSoarData/kobo/bfvsleep &

This kicks off bfvsleep in the new thread that runs as Nickel is starting up. bfvsleep contains the following commands.

sleep 10
stty ospeed 57600 ispeed 57600 -F /dev/ttymxc0
stty -F /dev/ttymxc0 raw
echo '$SLX*'>/dev/ttymxc0