I was testing again and figured it out this morning, I’m not sure if this is obvious for someone who already works with other LoRa modules, I was completely confused about it.
Well after some research and comparisons done I decided to make an schematic for this module connected to Arduino, base in this example https://github.com/sandeepmistry/arduino-LoRa
#My apologies, made a bad a diagram, in my real modules I have the antenna, but not in the diagram #Also is necessary the proper power supply for the system (3.3V) Cheers
HPD13A connected to Arduino
MODERATOR NOTE: do NOT use this diagram to create your node if you are running the UNO at 5V (normal operating mode), it connects 3.3 volt pins to 5 volt which will damage the LoRa module. Also the mandatory antenna is missing which will result in damage to the module as well.
Are the I/O pins of this module 5V tolerant? If not specified as such you are going to destroy the module by connecting it directly to Uno I/O pins.
Use level conversion…
Well, I haven’t tried them with 5V directly, but I connected them to the 3.3V pins from the arduinos and then programmed the Sender and Receiver example from the link above and it worked, the HPD13A modules didn’t get hot at all.
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what is your opinion?, in the past I tried using SIM800L modules (gsm), and the voltage was a big problem and I’ve got to use a couple of bateries, but in this case anything happened.
Unless you are 100% certain the HPD13A is a 5V tolerant device, I would remove that connection diagram.
Anyone finding the diagram might assume, that since its posted on the TTN forum, its an accurate and safe way to connect the HPD13A.
A lot of UNOs can be limited to 50mA on the 3.3V supply pin, not enough for a LoRa device, so using the UNO 3.3V supply will likley lead to unstable\unreliable operation.
Additionally, the ‘diagram’ shows no antenna connection, operating it without an antenna is another way to destroy a LoRa device.
And the quote from the Github repository you used to formulate the diagram;
“If your Arduino board operates at 5V, like the Arduino Uno, Leonardo or Mega, you will need to use a level converter for the wiring to the Semtech SX127x module. Most Semtech SX127x breakout boards do not have logic level converters built-in”
You are mistaken. You are trying them with 5V directly. May-be not the power connection, but you have connected all input pins to 5V because the Uno drives them to 5V when the output level is high.