I am using a 12Vdc source into a Tobsun 12Vdc to 5Vdc converter. That 5v from converter is powering the mega2560 and the mega2560 is powering the HC-05 from the 3.3v onboard. Now when I plug in the 12V to the circuit, the mega2560 powers just fine but the HC-05 does not power on with it. If while the converter has the 12V source connected and I unplug the mega card then re-plug it back in, the HC-05 powers on with the card. Is there something I can put inline to make the hc-05 power on with the card? It is acting like the mega2560 is not getting enough power right away to power on the HC-05 module when I connect 12V to the dc converter. Any help would be appreciated as I am at a loss on how to resolve this.
What voltage range is written on the back of the HC-05.
Does 3.3volt fall into that?
What pin of the Mega did you connect the 5volt power of the buck converter to.
Which pins did you connect RX/TX of the HC-05 to, and did you use a voltage divider on the RX pin.
Leo..
Hi Leo,
Thanks for the reply, here are the answers to your questions.
The HC-05 range on back of module says 3.6v - 6v I have tried to hook it up the converter 5v and mega 5v sources with the same issue.
I connect the mega card using the barrel connector to the 5V Tobsun dc converter.
Module RX connected to TX of Mega card and TX of Module to the RX of Mega card.
The bluetooth module works as needed off 3.3v, I just have to disconnect and reconnect the ground after I connect the 12V source to the circuit.
xxmeuccixx:
The HC-05 range on back of module says 3.6v - 6v I have tried to hook it up the converter 5v and mega 5v sources with the same issue.
It was a rhetorical question. It should of course be powered from the 5volt pin.
xxmeuccixx:
I connect the mega card using the barrel connector to the 5V Tobsun dc converter.
Did you look at the specifications of the Mega. The DC jack needs at least 7volt.
With 5volt on the DC jack, the Mega would only be getting about 3.5volt on the 5volt pin.
If your 5volt supply is reliable, then connect it directly to the 5volt pin.
xxmeuccixx:
Module RX connected to TX of Mega card and TX of Module to the RX of Mega card.
That will interfere with the USB<>Serial chip, which those pins are permanently connected to.
Use one of the OTHER hardware serial ports of the Mega. There are three spare ones (pin 14-19).
Study the Mega's MultiSerial example in the IDE.
Leo..
