Midi Edition
- Compatibility
- Midi vs Mini
- Use cases
- Disclaimer
- Bill of materials
- Quick start
- Settings
- Buttons
- GNSS receiver
- Enclosure
- Battery life
- Optional equipment
- Useful links
Midi Edition is a successor of SoftRF Mini Edition.
It is supposed to require minimal skills from a builder to begin with and gives an opportunity to evaluate if the SoftRF technology is appropriate for your needs.
The Midi is based upon third-party's hardware - Heltec Wireless Tracker board, which is available for direct purchase from manufacturer at more or less reasonable price (20+ USD).
Wireless Tracker is:
- a multipurpose ,
- DIY-friendly ,
- low power ,
- lightweight
- LoRaWAN GNSS assets tracker board.
The Wireless Tracker is an example of cutting edge technology. It contains:
- Espressif ESP32-S3FN8 SoC ;
- Semtech SX1262 Long Range Low Power RF Transceiver ;
- UniCore UC6580 L1 + L5/L2 bands GNSS receiver; it supports GPS, GLONASS, BDS, Galileo, NAVIC, QZSS ;
- 0.96" 160x80 SPI TFT display
| Type | Protocol | FLARM | OGN tracker | PilotAware | Skytraxx | SoftRF |
|---|---|---|---|---|---|---|
| Radio | FLARM AIR V6 |
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OGNTP |
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P3I |
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FANET+ |
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SRD 860 |
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| Data | FLARM NMEA |
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| Garmin GDL90 |
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Dump1090 |
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1 - it is necessary for a reader to distinguish the difference between statement "compatible"
and statement "fully compatible".
SoftRF implements only a reasonable minimum of the protocols specs.
No "bells and whistles" so far.
This is a picture of Mini and Midi Editions, side by side.
One can see that the new Edition is a little bit bigger than the Mini, that's why it's name is Midi.
| Edition | Mini | Midi |
|---|---|---|
| First appearance | 2020 | 2023 |
| SoC | Cypress PSoC 4100S | Espressif ESP32-S3 |
| Flash memory | 128 KB | 8 MB |
| SRAM | 16 KB | 512 KB |
| Wi-Fi | 802.11 b/g/n |
|
| Bluetooth | external LE (HM-10) | 5 LE |
| sub-1GHz radio | SX1262 | SX1262 |
| Battery | ext. Li-Ion | ext. Li-Ion |
| GNSS | GK9501 or AT6558 | UC6580 |
| Display | built-in 0.96" OLED | built-in 0.96" TFT
|
| USB |
2.0 FSClient/Host
|
|
| Air pressure sensor | external BMP280 | external BMP280 |
Same that the SoftRF Mini Edition has.
SoftRF firmware for Midi Edition is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
In general a lot of Chinese DIY electronics manufacturers are known to behave this way:
- sometimes they may not apply necessary Q.C. before releasing of a product from factory ;
- they may arbitrary change schematics and electronic components from one batch to the next one ;
- they may terminate manufacturing of a board just few month after initial production.
Author of SoftRF firmware:
- will reject any hardware related claims associated with Heltec Wireless Tracker development kit. Ask for support from seller or manufacturer ;
- reserves the right to suspend or terminate support of Heltec Wireless Tracker in the firmware at any time.
For the time being ( August '23 ) there were no critical hardware issues reported for current version of the Wireless Tracker kit. However things my change over the time...
If you have issues with bringing up your new Heltec Wireless Tracker or just not happy with the board - be prepared to execute your Purchase Protection plan.
| Number | Part | Qty | Picture | Source |
|---|---|---|---|---|
| 1 | Heltec Wireless Tracker 2 3 |
1 |  |
AliExpress 1 2 3 Amazon |
2 - 868 MHz variant is applicable for these world regions: EU, RU, NZ, SA, IN ;
915 MHz - US, CA, AU, KR, IL ;
433 MHz - CN .
3 - SoftRF firmware is designed to work with versions V1.0 and V1.1 of the Heltec Wireless Tracker. Other versions may or may not work.
| Number | Part | Qty | Picture | Source |
|---|---|---|---|---|
| 2 | SMA female to uFL adapter | 1 |  |
AliExpress |
| 3 | 868 MHz SMA dipole antenna 4 | 1 |  |
AliExpress |
| 4 | Antenna 868 MHz 4 |
1 |  |
EBay AliExpress 1 2 |
| 5 | 602248 560mAh Li-Po battery with JST 1.25mm 2pin connector | 1 |  |
AliExpress |
| 6 | Bosch BMP280 pressure sensor | 1 |  |
AliExpress |
4 - 868 MHz variant is applicable for these world regions: EU, RU, NZ, SA, IN ;
915 MHz - US, CA, AU, KR, IL ;
433 MHz - CN .
| Number | Part | Qty | Picture | Source |
|---|---|---|---|---|
| 7 | MAX3232 RS232 TTL adapter |
1 |  |
AliExpress |
| 8 | Bluetooth HC-05 |
1 |  |
AliExpress |
Use these instructions to start operating with your delivered Midi Edition board.
Description of Web UI settings is located here.
When unit is Off:
- press and release USER button to turn the unit On.
When unit is On:
| Button(s) | Function |
|---|---|
| USER | press and keep holding USER button for 2-3 seconds to turn the unit Off
|
| USER with RESET | enter into Espressif Service Mode |
| USER short after RESET | enter into bootloader mode |
The Heltec Wireless Tracker board is supplied with built-in GNSS module based on UniCore UC6580 chip.
A user may see the GNSS receiver model on a WebUI page:
One may try this page out to troubleshoot the GNSS related issues if any.
STL files of this enclosure are available on Thingiverse.
Current consumption from 3.7 Volt battery:
| Mode | Average current (mA) |
|---|---|
| Active | 130 |
| Sleep | 0.02 |
Operating time from a full charge depends on your actual battery capacity.
When battery charge level is getting low - the white LED will start flashing to indicate that charging is necessary.
When battery charge level is almost "zero" - the system will indicate "LOW BAT" message on TFT display for a few seconds then the device will enter into low power (deep sleep) mode.
| HTIT-Tracker | BMP280 |
|---|---|
| GND | GND |
| Vext | VCC |
| GPIO 6 | SDA |
| GPIO 7 | SCL |
Warning
Reported pressure altitude value may deviate from true value at any time.
There is an option to connect an external RS-232C device to UART pins of the Heltec Wireless Tracker MCU.
| Function | Pin |
|---|---|
| TxD | GPIO 43 |
| RxD | GPIO 44 |
Signal levels: 3.3 Volt
Transfer settings: 38400 bps, 8N1
You can use the WebUI Settings page to redirect NMEA/GDL90/D1090 output onto the Serial port/pins.
When wired RS232 connection to some legacy NMEA or GDL90 equipment is necessary - one may consider to use this type of adapters.
Heltec Wireless Tracker is a Bluetooth LE only device. To maintain compatibility with:
- old Android (4.2 or less) smartphones/tablets
- Naviter Oudie
one may consider to purchase an HC-05 Bluetooth Classic module as well.
SkyView EZ 
is a DIY companion device for SoftRF Midi Edition.
- Heltec product info
- Video
- Schematics: V1.0 , V1.1
