Show HN: We built the smallest dual-band aircraft tracker

Pants for Birds is excited to present a caller merchandise successful the ADSBee family of open-source ADS-B receivers: ADSBee 1421!

In the past year, developers and enthusiasts person brought ADSBee 1090U’s unfastened root craft search exertion to a wide scope of platforms, from airdrome crushed stations to drones to upwind balloons.

While moving intimately pinch immoderate of our customers, we discovered that galore applications person a request for an ultra low-power, low-cost ADS-B receiver tuned specifically for craft observe and debar applications, without the request for the afloat characteristic group of ADSBee 1090U.

Simultaneously, Semtech released their fourth-generation LoRA IP connected a spot called the LR2021, which includes a caller precocious spot complaint OOK reception RF frontend and demodulator. This caller spot neatly containerizes an RF architecture that was antecedently implemented successful civilization discrete components (like successful ADSBee 1090U and astir different receivers) drastically shrinking some shape facet and powerfulness dissipation required for receiving Mode S packets. Combined pinch a debased powerfulness RF MCU, the LR2021 provides the cleanable ground for a ace small, debased power, debased costs dual-band ADS-B receiver. We already had the cleanable campaigner portion for the RF MCU successful TI’s CC1314, the next-generation loop of the TI CC1312 that we usage for receiving UAT (and soon, different sub-GHz craft search protocols), connected the ADSBee 1090U.

At the opening of 2026, we embarked connected a creation effort pinch these 2 MCUs, dubbing the operation “ADSBee 1421”, based connected a concatenation of the constituent portion numbers (TI CC1314 and LR 2021). In statement pinch our existing portion conventions, a la ADSBee m1090, we added an “m” to the opening of our portion to denote that it would beryllium built arsenic a solder-down module, for easy integration into immoderate civilization PCB design. Thus, the ADSBee m1421 was born!

ADSBee m1421 features dual-band ADS-B reception (Mode S and UAT), including support for UAT uplink protocols (TIS-B postulation / FIS-B weather). Perfect for wide and powerfulness constrained embedded applications, m1421 weighs little than 2 grams, draws little than 60mW of power, and features an ultra-small shape facet of 23.4 x 14.5mm x 2.7mm.

ADSBee m1421’s firmware and schematic are unfastened root nether a GPL v3 license. All craft position decoding and search logic is unified pinch our wide adopted ADSBee 1090 firmware, and disposable for building successful unreality CI.

Output protocols supported by ADSBee m1421 see GDL90, MAVLINK1, MAVLINK2, Aircraft JSON, CSBee, and earthy packets, pinch much protocols to come!

ADSBee m1421 is disposable successful some standard and NDAA-compliant variants. The modular version of ADSBee m1421 costs conscionable $48 successful azygous quantities, and moreover little astatine volume. Currently, our NDAA compliant version is much costly ($75), but we are actively moving connected expanding manufacturing capacity successful the USA successful bid to bring our NDAA compliant version to costs parity pinch our modular module version. We expect to scope costs parity astir the extremity of this twelvemonth (December 2026).

Not really! ADSBee 1421 and ADSBee 1090 bid receivers person very different architectures, and are bully for different things. ADSBee 1421 uses the LR2021 for a highly integrated, debased powerfulness Mode S receiver, but the LR2021 has immoderate shortcomings compared to the discrete RF constituent + RP2040 PIO receiver architecture connected ADSBee 1090. Most notably, successful bid to execute satisfactory move scope (receiving some very adjacent and very acold distant craft simultaneously), the LR2021 has to beryllium tuned to perceive to only 1 Mode S packet type; Downlink Format 17 aka. ADS-B. In short, it’s awesome astatine seeing wherever planes are, but you won’t person squawk codes, and you will besides person less non-ADSB packets. This is mostly not a origin for interest successful observe and debar applications, but tin beryllium a drawback for information gathering usage cases. ADSBee m1421 features a precocious grade of configurability exposed done our firmware, truthful reception utilizing the Mode S preamble (and therefore, reception of each Mode S packet types) is supported, but this results successful poorer move scope (close-in craft tin person mediocre reception).

Additionally, successful its high-throughput configuration, Semtech LR2021 does not support per-packet timestamps nor RSSI. This tin beryllium a drawback for users attempting to usage ADSBee m1421 for multilateration applications (tracking craft utilizing a receiver array and clip of presence of each packet). We person immoderate ideas successful the backmost of our caput astir really MLAT mightiness beryllium added to our ADSBee 1421 firmware, but this still requires a bully woody of tinkering and testing truthful we aren’t supporting it arsenic an “out of the box” capacity astatine this time.

So, which 1 should you choose?

Full-featured dual-band ADS-B pinch each the bells and whistles, wherever powerfulness / shape facet / costs are secondary to instrumentality functionality. Built-in WiFi/Ethernet/USB connectivity: ADSBee 1090

Dual-band ADS-B capable for craft tracking, without MLAT timestamps / per-packet RSSI / non-DF17 packets, wherever powerfulness / shape facet / costs are very important. UART interface only: ADSBee 1421

ADSBee m1421’s LR2021 is rather a tin radio, and not conscionable erstwhile it’s utilized arsenic a Mode S receiver! We’ve surgery retired the LR2021’s 2.4GHz frontend arsenic a due coplanar waveguide (labelled “LRHF” connected the module), allowing customers to reuse the LR2021 arsenic a mesh power transmitter / receiver pinch LoRa and different supported protocols. ADSBee’s SYNC statement allows an outer big MCU to put the CC1314 to slumber wrong 25us, handing complete afloat power of the LR2021. This gives you the champion of some worlds successful a elastic embedded application, arsenic the CC1314 retains each craft information successful its slumber state, truthful you tin time-share betwixt mesh power and Mode S reception arsenic needed. Note that ADSBee m1421 does not presently transportation immoderate module-level EMI certification, and it must only beryllium utilized arsenic a transmitter successful compliance pinch section regulations.

Oscilloscope seizure of the LR2021 RESET statement (yellow) being released by m1421 aft SYNC statement (green) goes high, persisted crossed hundreds of handovers. ADSBee m1421 is “well clear” of the LR2021 by astir 25us.

Plug and play mode: get a devkit!

If you want to get started correct distant pinch ADSBee 1421, you tin prime up an ADSBee 1421 Developer Kit. This includes an ADSBee m1421 module soldered to our unfastened root minimum shape facet bearer committee (forming what we telephone the ADSBee 1421). We built a abstracted RP2040 Zero committee arsenic a USB to Serial span and automatic instrumentality programmer, allowing you to easy pass pinch your ADSBee 1421 and update its firmware from immoderate machine (of course, the firmware root codification for the programmer is besides unfastened source, truthful you are invited to build your own, aliases easy adhd automatic firmware update capabilities to your ain big microcontroller).

Once an ADSBee 1421 is configured and has its firmware updated, you tin plug it correct successful to immoderate instrumentality that accepts ADS-B information complete UART, for illustration a drone formation controller aliases your ain big MCU / CPU / whatever. We’ve built a group of unfastened root package devices disposable astatine adsbee.aero that will fto you link to and configure your ADSBee 1421 devkit complete USB serial, arsenic good arsenic position a unrecorded representation of craft being received!

In the adjacent future, we scheme to connection ADSBee 1421 without a programmer, and without the SWD debug header attached. Stay tuned arsenic we ramp up production!

Product creation mode: build your ain board!

We person rather a fewer customers who person already put ADSBee m1421 onto their ain bearer board. Our KiCAD footprint files, symbols, and 3D models are freely disposable for ADSBee m1421, and our ADSBee 1421 minimum shape facet bearer committee reference creation has each of its creation files uploaded here, making it easy to get started pinch your ain design.

For wide accumulation usage cases, ADSBee m1421 ships successful trays of 50, making it easy for immoderate statement shaper to spot a module onto your ain PCB design. The serial number explanation connected apical of each ADSBee m1421 is reflow safe and chemic resistant, and ADSBee m1421 tin withstand up to 2 reflow passes without rumor (so you tin put it connected the apical aliases bottommost of your PCB without immoderate typical precautions).

A tray of ADSBee m1421 modules, basking retired of the oven! The instrumentality is to retrieve to food the tray earlier baking, aliases other they thin to stick.

For very precocious measurement applications (purchase quantities supra 1k, aliases estimated yearly usage supra 12k pcs/yr), we person further measurement pricing tiers available. Get successful touch pinch maine ([email protected]) and I’ll beryllium happy to supply a civilization quote.