A little while ago, I received a bunch of ESP32 PICO Core development boards which were based on Espressif Systems ESP32-PICO-D4 system-in-package with ESP32, 4MB SPI Flash, and other components. The advantage of such chip is that is requires less external component, and allows for smaller designs. For example, the boards I received would leave two row of pin on each side of the board, while most other ESP32 boards will only expose one row on each side.
I used the board to play with Micropython ESP32 port, and later-on when I launched a giveaway of 8 of the boards, I found out the name had changed to ESP32-PICO Kit, with the documentation listing v3 with all pins connected to male headers, and v4 with 6-pin not connected to a male header as shown in the photo below. Both versions of the board also have a different pin layout. But you don’t need to care since AFAIK v3 was never up for sale.
ESP32-PICO-KIT v4 however has now just launched, and Electrodragon offers it for $10 plus shipping.
- SiP – ESP32-PICO-D4 802.11 b/g/n WiFi + Bluetooth LE system-in-package
- 3D antenna
- USB – 1x micro USB port for power and programming; CP2102 USB-TTL Serial Bridge
- Expansion – 2x 20-pin headers with I/O and power signals. 2x 17-pin male headers soldered
- Misc – EN and Boot buttons, on board power indicator LED.
- Power regulator – AMS1117 3.3V regulator
- Auto reset circuit
- Dimensions – 51 x 20 mm
Other ESP32-PICO-D4 based boards have been launched such ESP32-PICO motherboard sold for $16 on Tindie, or TTGO T7, recently discovered by Time4EE, that can be purchased for $8.50 plus shipping on Aliexpress. The latter is however quite wider than the official Espressif devkit (estimated dimensions: 50×30 mm), but does provide a battery connector
Standard ESP32 boards can now be purchased for as low as $5, so boards based on the SiP are currently a little bit more expensive, but I’d expect the price difference to come down overtime.