Review on HiLetgo HC-05 Bluetooth RF Transceiver Module - Wireless Master Slave Integrated Bluetooth Communication for Arduino with 6 Pin Wireless Serial Port Connection by Robert Gomatham

Built in 5 pin 3.3V voltage regulator One of those 5 pins will enable the output and connects to the EN pin. The display shows a 5 pin regulator and the display has a diagram showing a 5 pin regulator. Big! But what I actually got was another HC-05 with a regular 3-pin voltage regulator, with no output enable pin. I can't use it. This pin enable feature is important because by adding an external connection to the onboard switch and connecting that and the EN pin to the two output pins on my microcontroller, I can put the module into AT programming mode with software alone, without the switch to touch or manually disable and re-enable the module. I use this in the product, in the case, and through the software I give the end user the ability to rename bluetooth to whatever they want. Without a 5-pin voltage regulator and an output enable function, I can't do it as conveniently. I have returned 2 purchased modules. On the other hand, Sunhokey advertised a 5 pin regulator and I got it and they get a good review of the product. Here is a link to their ad: https://www.amazon.com/gp/product/B07BRM94MS/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1.