boylesg
December 29, 2017, 5:18am
1
I have a HC-05 connected to an arduino mega via Serial2.
And I have a MIT App Inventor app running on my android phone.
I have an issue where I can successfully send serial data from my andoid phone to the arduino mega.
But I can't receive serial data on my android phone from the arduino.
The connections between the arduino and the HC-05 are definitely correct upon checking with my multimeter.
I have a voltage divider between arduino Tx and HC-05 Rx, consisting of a 10k resistor and a 18k resistor.
But I notice that most people seem to use voltage dividers in the range 1k to 3k.
And I have noticed that the HC-05 LED does not flash when the arduino is transmitting serial data to the HC-05. I assume the LED should be flashing?
Is the voltage divider I have used likely to the cause of the failure to receive data from the arduino/HC-05?
boylesg
December 29, 2017, 6:05am
2
Tried binding to the Arduino/HC-05 from my Windows PC and sending/receiving serial data.
Same problem - can send data to the Arduino OK but I can't receive it from the Arduino
boylesg:
I have a voltage divider between arduino Tx and HC-05 Rx, consisting of a 10k resistor and a 18k resistor.
But I notice that most people seem to use voltage dividers in the range 1k to 3k.
Your higher values may be to high for the input impedance or capacitance of the bluetooth device.
boylesg
December 29, 2017, 11:02am
4
Never mind I found what I did wrong.
I soldered in a 100k resistor instead of a 10k resistor in my voltage divider.
I used the blue metal film resistors and I find their color coding less intuitive.
boylesg:
I soldered in a 100k resistor instead of a 10k resistor in my voltage divider.
I used the blue metal film resistors and I find their color coding less intuitive.
Yes, they can be misleading, I have come to the habit of measuring ALL my resistors like that before putting them in circuit.
