I recently found this model with the ID 'HW-0519' on it. It can be found online (HW-0519 in Aliexpress) and is sold for the purpose of converting UART to RS485 communication using Arduino devices. The MAX485 module (MAX485 in Banggood) is the more commonly used module for this purpose and has been used in many projects. The MAX485 has the following pins DI (data in), RO (receiver out), DE (Data Enable), RE (Receiver Enable), VCC, GND and the 'A' and 'B' pins for the RS485 device (Shown below).

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The HW-0519 module, has a slightly different pin configuration, and I can't seem to wrap my head around it. It has Tx and Rx pins, which I am guessing match up with RO and DI respectively, but don't have enable pins. They have the VCC and GND pins along with the 'A' and 'B' pins, but also come with this pin marked in Chinese. I translated it using Google translate and it translates to something similar to 'Ground'. Which is not connected to the GND pin though (Shown below).

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Does anyone know whether I can use the HW-0519 module in the same manner as the MAX485? If so, are there any libraries written for this module? I want to use the module for communication with a pH sensor like the one in this link.

  • 1
    Looks like the HW-0519 module implements automatic TX/RX mode switching for you. – Majenko Apr 11 at 11:10
  • @Majenko does that mean I need not concern myself with controlling the direction of the data when writing the code with this HW-0519? – C Vith Apr 13 at 10:02
  • @Majenko because, from what I understand, the DE and RE in the MAX485 module are usually connected together to one pin in the microcontroller and set to HIGH when transmitting and LOW when receiving. – C Vith Apr 13 at 10:09
  • Theoretically, though there may be baud rate considerations to take into account and pre/post send delays or something. I don't know how the module works, so YMMV with it. – Majenko Apr 13 at 10:13

I did a bit of research and found others who use this particular component for their RS485 communication purposes. It is difficult to get clear info because the device goes by different names and the most commonly used name is MAX485 (name of the IC), which is used interchangeably for both the components shown in the question.

It seems the more I search for the 'HW-0519', the more names I find for it. So far, it goes by the name 'MAX485', 'XY-017', and 'XY-K485'. A clear advantage for this 'HW-0519' is that it does not require D or R enabling, just straightforward Tx and Rx. It also has LEDs to show the data transfers. I found a project that used this module here. I am unsure about their pin connections from the ESP-32 though. It looks like they've connected the ESP-32's TX2 to the HW-0519's Tx, and the RX2 to the Rx. I thought it should be the other way around.

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