LIDAR-Lite 3 Laser Rangefinder question

josh0222 · September 2, 2020, 10:41am

When I use LIDAR-Lite 3 Laser Rangefinder, I keep encountering the range finding value that the sequence window cannot output. The following file is the picture of my problem

. How can solve the problem?

geraldinebc15 · September 3, 2020, 1:33am

Hello @josh0222 and welcome to the RobotShop forum!

I think this will help you out

https://learn.sparkfun.com/tutorials/lidar-lite-v3-hookup-guide/troubleshooting

Let us know how it goes

josh0222 · September 12, 2020, 5:44am

I have replaced all the cables and electronic components. And simply using this program(see following website) to test lidarlite’s ranging function, it still presents the same problem. So I am wondering if it is possible that lidarlite is damaged?

github.com

garmin/LIDARLite_Arduino_Library/blob/master/examples/v3/GetDistanceI2c/GetDistanceI2c.ino

/*------------------------------------------------------------------------------

  LIDARLite Arduino Library
  v3/GetDistanceI2c

  This example shows how to initialize, configure, and read distance from a
  LIDAR-Lite connected over the I2C interface.

  Connections:
  LIDAR-Lite 5 Vdc (red) to Arduino 5v
  LIDAR-Lite I2C SCL (green) to Arduino SCL
  LIDAR-Lite I2C SDA (blue) to Arduino SDA
  LIDAR-Lite Ground (black) to Arduino GND

  (Capacitor recommended to mitigate inrush current when device is enabled)
  680uF capacitor (+) to Arduino 5v
  680uF capacitor (-) to Arduino GND

  See the Operation Manual for wiring diagrams and more information:
  http://static.garmin.com/pumac/LIDAR_Lite_v3_Operation_Manual_and_Technical_Specifications.pdf

This file has been truncated. show original

geraldinebc15 · September 12, 2020, 4:08pm

Hi josh,

Did you try adding the pull-up resistors and decoupling capacitor?

josh0222 · September 13, 2020, 9:48am

I connected it according to the lidarlite part of the wiring diagram below. It uses decoupling capacitors but no resistors.

geraldinebc15 · September 13, 2020, 5:26pm

You could try adding 4.7K external pullups to 5V for the SCL and SDA lines.

Also, please check this topic

If the Lidar Lite still does not work using an external power supply please create a support ticket with your order or invoice number and a link to this topic.

Regards

josh0222 · September 14, 2020, 2:17am

I have a question. I use the 12C code and connection method. In the operation manual, the 12C connection method does not require an external resistor. It is PWM that requires an external resistor. In addition, I did not have additional resistors when I was operating, but it worked successfully. I started to encounter this problem after a certain operation, so I was wondering if the wiring was broken. The following link is my previous arduinoLidarScanner arduino code.txt (1.7 KB) code, you can refer to it.

josh0222 · September 14, 2020, 6:34am

If the input voltage is only 4.5V, does lidarlite fail to work? Does the input voltage have to be 5V?

geraldinebc15 · September 14, 2020, 2:24pm

The I2C connection could benefit from pull up resistors, you can read more about this here:
https://learn.sparkfun.com/tutorials/i2c/all#i2c-at-the-hardware-level

I started to encounter this problem after a certain operation, so I was wondering if the wiring was broken

Did you change the hardware in any way? Or just the code?
I2C is a sensitive protocol so there might be a problem with the connection
Have you checked the continuity?

Does the input voltage have to be 5V?

LIDAR-Lite v3 units require between 4.5V to 5.5V of DC power to operate and can draw up to 135 mA of current during continuous operation (105 mA at idle).

josh0222 · September 15, 2020, 10:07am

It should be said that I first use this code to achieve the scanning function (such as txt attachment). The first few times the operation was still very smooth, but after a certain operation, it started to encounter the problem of incorrect output. So I changed the cable first, and then used the code on github to independently test the lidarlite ranging function, but it couldn’t solve the problem. So I wonder if there is a problem with lidarlite. Because the code should be executable in theory, there is no error when compiling.
LidarScanner arduino code.txt (1.7 KB)

josh0222 · September 15, 2020, 10:09am

So I also have to confirm whether the current is operating at 135mA?

josh0222 · September 15, 2020, 2:53pm

By the way, how should the 4.7K pull-up resistor be added to the wiring diagram, in series or in parallel?

o_lampe · September 16, 2020, 8:17am

Add the pullups the same way as the capacitor to the gnd wire, but to the green and blue wires.
AFAIK , the Arduino Uno has pullups onboard for I2C (my Mega2560 has). If you have a multimeter, you can check the resistance between SCL and 5V / SDA and 5V.

geraldinebc15 · September 16, 2020, 4:42pm

So I also have to confirm whether the current is operating at 135mA?

If the unit had worked previously the problem is not the power source so it is not necessary. It is probably a connection problem.

how should the 4.7K pull-up resistor

If you have an Arduino Uno that already has built-in pullup resistors (you might have to enable them)

digitalWrite(SDA, 1);
digitalWrite(SCL, 1);

However, these internal resistors might be too “weak”, that is why it is advised to add 4.7K external pullups to 5V for the SCL and SDA lines.

josh0222 · September 23, 2020, 11:15am

Is the 4.7k pullups resistor added like the following picture?

josh0222 · September 23, 2020, 11:18am

Where should these two lines of definition be added to my code?
digitalWrite(SDA, 1);
digitalWrite(SCL, 1);

code.txt (475 Bytes)

josh0222 · September 23, 2020, 11:23am

Sometimes when compiling my code, there will be an error in orange in the figure below. Will this affect the operation?

geraldinebc15 · September 23, 2020, 3:50pm

Yes, like this:

PS: Sorry for my really bad drawing

geraldinebc15 · September 23, 2020, 3:54pm

You can add it to void setup()

geraldinebc15 · September 23, 2020, 4:01pm

The errors don’t seem to be related but you can try searching for those packages to avoid getting those messages

https://forum.arduino.cc/index.php?topic=461880.15