I am looking for differences between HC-05 and HC-42 Bluetooth modules for Arduino. I could not find an answer by searching google.

Both products have 6 pins and accept master and slave but I could not find further details on the differences.

1 Answer 1


It's different technology. the HC-05 uses the old Bluetooth 2.0 standard. The HC-42 in contrast uses BLE (Bluetooth Low Energy) in version 5.0.

So you have to decide what technology you want to use, either classic Bluetooth 2.0 or Bluetooth Low Energy 5.0.

  • Anecdotally, a few years ago I tried to use BLE and it had much less library support. Not sure how it is now.
    – qwr
    Feb 16, 2022 at 21:46

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