Hi.
I’m trying to control two Lidar Lite V3s with my RaspberryPi3.
I think I must change their i2c addresses one by one with setting PowerEnable Pin.
I am considering to connect each PowerEnable Pin and raspberry pi’s GPIO pin respectively.
Raspberry Pi’s GPIO pin supply 3.3 V for output,but I’m not sure this is sufficient or not.
Manual says PowerEnable pin is internal pulled-up but I cannot find how many volts it is.
If someone knows in detail, I want to know the information.
Any help will appreciate.
Hi,
Here are answers to your question & comments:
That sounds like it should work just fine with some precautions. See below for details.
The (external) interface of the LIDAR-Lite v3 is 5 V DC. Therefore, it is safe to assume the pull-up resistor will be at that voltage, too.
For starters, as you mentioned above, there is this information:
From the instructions available on the product page under Useful Links we can read on page 4 the following:
This basically tells us that you need to drive the pin low to turn off the device, which any microcontroller pin should do without issue. The only potential risk is the RPi (which uses 3.3 V DC) being pulled to 5 V DC when outputting high by the pull-up resistor of the LIDAR-Lite (unlikely, since the pull-up is most likely very weak, in the range of 30-50 kOhm).
That being said, there is a sure way to protect the pin: add a resistor in series. You should be fine with a typical resistor value, such as 333 Ohm or 1 kOhm. This resistor will act as a current limiter, therefore preventing the 3.3 V DC pin of the RPi from getting damaged by a potentially 5 V DC input pin.
Sincerely,
Thank you for the answer!
I will try connect GPIO pin and PWREN via 1K resister.
