arduinointerrupts
I m trying to trigger an Arduino Mega interrupt pin from a 3.3V sensor.
This voltage doesn't seem to be enough, since Arduino recognizes the interrupt only when I move the wire (probably since it causes the voltage to spike).
Can I use a transistor or any other solution to send 5V to the interrupt from a 3.3V source?
An Arduino Mega has “only” 24 pin change interrupts for its 80 pins. Still, that may be enough for the original poster, and he may not have been aware of this possibility, because the “INT" pins have API support in the Arduino environment, while the pin change interrupts don’t.
Here’s some fairly elaborate code to attach to pin change interrupts
The problem with hobby related solutions is documentation is limited and not spec'd like commercial components or modules.
It is possible that it may work but make a block wiring diagram and consult with the OEM is advised. Mind you I don't know if they have adequate support for your question as these are built in China.
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It appears that your ultrasonic load is TTL so there is no problem switching 5 at the same time with a BEC, but I wonder if you have considered the effects of crosstalk on firing all at the same time. They indicate a 15deg detection angle but this would depend on the reflection angle of objects you wish to detect. There may be phasing issues with reflection cancellations like having 5 tweeters directed in a room. Reading the response of each echo in parallel with a time interval count won't be a simple textbook result with non-smooth objects with 5 senders.
YOu can test your orthogonal array design with any signal pulse generator and look at the signal on a parallel port logic analyzer or scope to ensure what you are design will work.
Power drive is the least of your concerns from these low power devices. Noise avoidance from conducted and radiated sources will be paramount and design of the transponder array must come first. I would spend some time on testing this part 1st to identify all the electrical, physical, acoustic, EMI, thermal, vibration both conducted and radiated sources of interference and how each affects your SONAR expectations with different objects. Will it be microphonic with vibration or loud pulse noises. How well does it reject other ultrasound sources of noise? Will the TTL Echo output change in pulse width with signal strength or just the delay time.
Will you get echos from the wrong sender due to corner refection effects.
Best Answer
Can be done with a simple transistor and two resistors. When the 3.3v pin is pulled high, the arduino's interupt pin is pulled low.
simulate this circuit – Schematic created using CircuitLab