FlockOne

FlockOne

This is a cheap STM32F0 based board with a total DIY cost around $4 per board. Users with previous soldering experience should have no problem building it with just a soldering iron.

If you have never soldered SMD components, don't be afraid! All the components but the LoRa module are very cheap, so this design is also a good project to get you started with SMD. Just make sure to use a fine tip, tweezers and copious amounts of flux.

BOM

• 1x STM32F030F4P6 (10pcs, ~$0.35/pc)
• 1x Ai-Thinker Ra-02 (1pc, ~$2.65/pc)
• 1x 100 nF 0603 Capacitor (*) (100pcs, $0.01/pc)
• 2x 4.7 uF 0603 Capacitor (*) (100pcs, $0.01/pc)
• 2x 10 kOhm 0603 Resistor (*) (100pcs, $0.01/pc)
• 1x 330 Ohm 0603 Resistor (*) (100pcs, $0.01/pc)
• 1x MIC5219-3.3BM5 (10pcs, $0.09/pc)
• 1x 0603 LED (*) (100pcs, $0.01/pc)

(*) Listing with multiple values, select the right one!

PCB

Use the FlockOne.zip file to order the PCB from your fabrication service of choice. Some popular manufacturers for hobbyists:

• JLCPCB: ~$7 for 10 boards + shipping (~$0.70/pc)
• OshPark: ~$2.85 for 3 bords + shipping (~$0.95/pc)

Antenna

Any 433Mhz properly tuned antenna should work, there's no reason to use a high gain one. The RA-02 module includes an IPEX connector, so if you plan to use an antenna with a different connector (e.g. SMA) you should buy a pigtail too. Make sure to pick an ommnidirectional one. These are some examples:

• 433MHz Spring Antenna (1pc, ~$0.58/pc)