Monday 14 March 2022

BlueFlyVario_Bluetoooth_USB_v22 released

I really enjoy releasing new vario designs. I think this is the best base model Bluefly yet, even though this latest release has come about because of the crazy chip crisis. The v22 is the first model released in 2022. 

This Bluefly model provides a bluetooth connection to work with an app on your device. For most pilots that will be XCTrack on Android, or Flyskyhy on iOS. The USB connector is used for charging or to provide a USB serial port connection to adjust hardware settings. 

It looks the same as the last version, but there are important changes inside. 

Hardware changes

The biggest change in this model is that I have moved to a new processor, the PIC32MM0064GPM028. For most of the Bluefly history I have been using a 16 bit PIC24F processor. However, the chip crisis meant that these became impossible to purchase and I have run out. Over the last year I have been experimenting with other processors, but in the end the choice was made for me when I had to select what was available in the quantities needed. I am very lucky that my workflow allows me the agility to make changes quickly. 

The new processor has three UART instead of two, and its low power properties has allowed me to implement a new power scheme. This has resulted in a lower overall part count which results in less production mistakes to test and fix (the cost of little components is negligible compared to the effort in production for each component). 

In most other respects the hardware design of the vario is the same as the previous BlueFlyVario_Bluetooth_USB_v12.3; same case, same button, same pressure sensor, same bluetooth chip, and the same USB chip. 

This is the first vario where I have not exposed spare pins for experimenting. I have found that this is something that most pilots do not use or need. In the future I might produce an experimenter's version of this model. 

You might notice there are some pads which are not populated with components. I plan to use the same board for a new Bluetooth_GPS_IGC_v22 model. It will be a while longer until I have that new firmware tested and that model ready for release. 

Firmware changes

Changing to a new processor has required a rewrite of about half of the code. The use functionality is pretty much the same, with a few new hardware settings and some optimisation of parts of the code. In addition, the new processor is well supported by a Microchip library and in the MPLAB X IDE. This should make future tweaks to the firmware easier to roll out. 

There is new code to support the new power on/off arrangements. For the user it will feel the same as before, but now when you power down the vario it turns off one of the voltage regulators (which powers off everything other than the processor) and puts the processor into a very deep sleep mode. In this mode the processor consumes about 0.06 mA, but it still responds to a button press to reboot the vario and start it up again. A fully charged battery will last over two years in deep sleep mode, but if you do not plan to use the vario for more than a year I recommend disconnecting the battery. 

Under the code there is also a new version of the ds30 bootlaoder. It is the commercial version and is designed for this device. If I release firmware updates expect a new post describing how to use it. 

What is in the box

The box contains only the assembled vario, with some packaging to keep everything in place and to avoid the button being turned on. 

This model is shipped fully assembled by default.

Unboxing and first use

When your vario arrives, do this:

  1. Remove it from the packaging. 
  2. Remove the packaging and tape protecting the button from being turned on in transit. The low profile clear button is difficult to turn on accidently in normal use. 
  3. Short press the button. You should hear the vario turn on. See here for an explanation of the beeps and lights:
  4. Plug in microUSB cable to a charger or a computer. The red light indicates charging. 
  5. Connect it to your Android ( or iOS device (
  6. Consider connecting to the BFVDesktop application to adjust the settings. I do not think this is necessary for most pilots - I have chosen settings which I think work best.  
  7. You might want to add some velcro to secure it to your flight deck or a lanyard (