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.

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.