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Board Revision History

The Original BlueSMiRF

Back in April 2005, we released the original BlueSMiRF (Bluetooth Serial Miniature RF) Link, which featured BlueRadio's WML-C40AH Bluetooth modems. It was released in two variants that came with either a 4-pin header on the basic BlueSMiRF or a 6-pin header on the extended BlueSMiRF, using the following pin configuration (CTS)/PWR/GND/TX-O/RX-I/(RTS).

Basic BlueSMiRF

Basic BlueSMiRF

Extended BlueSMiRF

Extended BlueSMiRF

Silver, Gold, and Mate Header

Eventually, the Bluetooth modems manufactured by BlueRadio were discontinued and we transitioned to the RN-41 and RN-42 modules from Roving Network.

Gold vs Silver

The primary difference between the RN-41 and RN-42 modules was their range/transmit power. The BlueSMiRF Gold featured the RN-41, a class 1 Bluetooth module that had a range of 100m, but utilized more power. Meanwhile, the BlueSMiRF Silver featured the RN-42, a class 2 module with lower power consumption and a range limited to 10m.

BlueSMiRF Gold (RN-41)

BlueSMiRF Gold (RN-41)

BlueSMiRF Silver (RN-42)

BlueSMiRF Silver (RN-42)

Mate Header

With this revision, we also settled on a 6-pin layout to breakout the flow control pins of the serial interface. Additionally, in response to the growing popularity of miniaturized development boards, like the Arduino Pro and Pro Mini, we introduced a new variant with a compatible pin layout. The BlueSMiRF Mate variants had a pin layout ( GND/CTS/VCC/TXO/RXI/RTS) that matched the USB-to-Serial adapters that were used to program and interface with the development boards. This allowed users to easily extend the capabilities of their board with the BlueSMiRF Mate.

Pin layout between BlueSMiRF & Bluetooth Mate

A comparison of the pin layouts between the Bluetooth Mate and regular BlueSMiRF

BlueSMiRF mate connected to serial programming headers

BlueSMiRF Mate connected to the headers for the serial programming interface of the Arduino Pro.

BlueSMiRF v2

Just as the Bluetooth modems from BlueRadio were discontinued, production of the modules from Roving Network also ceased and in 2021 we sold the last of the BlueSMiRF Gold and Silver. Fast forward to January 2024 and the BlueSMiRF has arisen once more! The new BlueSMiRFs v2 features a few upgrades:

  • Features an ESP32-PICO-MINI-02 module programmed with our open-source firmware
  • We have three variants with different connections to simplify hooking up the BlueSMiRF to your project
    • The PTH pad and male header variants have fully, adopted the pin layout from the Bluetooth Mate
      • RTS/RXI/TXO/VCC/CTS/GND
      • Pin labels are now provided on both sides of the board
    • On the JST variant, the pin layout and JST connector matches the serial radios
  • A user button has been added to simplify pairing, triggering various modes of operation, and resetting the factory defaults
  • Upgraded the voltage regulator to the APA2112K 3.3V, 600mA for increased performance