Market forecasts for the Internet of Things promise billions of connected device in the years to come, but this won’t happen when LPWAN connector sensors cost $50 or more, so prices will have to come down. I’ve been told that one company is working on a WiFi + LoRa module that’s going to sell for $5 to $6 sometimes in 2017, but in the meantime, it’s possible to get some LoRa modules for less than $10,
albeit limited to 433 MHz frequency not the more common 868 MHz (EU) and 915 MHz (US), thanks to products such as AI-Thinker Ra-02 module.
- Chipset – Semtech SX1278 low power long range transceiver
- 433MHz frequency (420 to 450 MHz range)
- +20dBm – 10mW constant RF output vs. V supply; up to 300 kbps bitrate
- Supports FSK, GFSK, MSK, GMSK, LoRa and OOK Modulation Mode
- 127dB RSSI wave range.
- I/Os – 16x half through holes with half-duplex SPI communication, GPIO and power signals; 2.0 mm pitch
- Supply Voltage – 1.8 – 3.7V, default 3.3V
- Power Consumption – Receive < 10.8mA (LnaBoost closed, Band 1); transmist: < 120mA(+20dBm), sleep: 0.2 uA
- Dimensions – Estimated 16×16 mm
- Certifications – FCC/CE
- Temperature Range – -40 to +85 °C
I could only find the module on a company called Smart Prototyping selling the module for $9 plus shipping ($6.84), which amounts to roughly $15. But you could also get your hands on a pair of two SX1278 modules and spring antennas for $14.85 including shipping on Aliexpress, or about $7 per module.
The specifications of this cheaper module are basically the same as the AI-Thinker module. The seller is also promising to send the schematics and program by e-mail. If you look for DRF1278F on the web, you’ll find other websites selling it, for example it can be found on eBay for as low as $5.60 with one antenna and including shipping.
Thanks to Elia for the tip.