user77833: I need to read the distance data from a lidar in I2C using an Arduino Nano. Currently, this is the code I've written.
unsigned int readDistance()
{
  unsigned int dist = 0 ; // LiDAR actually measured distance value. static so we can return previous dist
  
  // step 1: instruct sensor to read echoes
  Wire.beginTransmission(0x10) ; // transmit to device 0x10
  Wire.write(2) ; // sets distance data address (addr)
  Wire.write(3) ; // sets distance data address (addr)
  Wire.endTransmission() ; // stop transmitting
  
  // step 2: wait for readings to happen
  delay(100) ; // datasheet suggests at least 100ms
  
  // step 3: request reading from sensor
  Wire.requestFrom(0x10, 2) ; // request 2 bytes (DIST_L, DIST_H) from slave device #0x10
  dist = Wire.read() ; dist += Wire.read() << 8; // calculate distance value, bit shift high distance
  return dist ; // return updated dist
}

But I have a feeling I'm requesting from the wrong data address', since I'm not getting the results I expect (ie. varying distance data). Furthermore, I used an I2C scanner which 100% confirms the lidar is on the (default address) of 0x10.
Datasheet of (TF02 Pro): https://www.unmannedtechshop.co.uk/wp-content/uploads/2020/01/TF02-Pro-Product-Manual-Alpha.pdf
Question: am i reading from the right data address
Any help would be appreciated.

user77833: Long story short, some i2c devices are configured such that data is only present in said registers after continually issuing 'read commands'.
In this case, the read command was: 5A 05 00 01 60
Amended code:
unsigned int readDistance()
{
  unsigned int dist = 0 ; // LiDAR actually measured distance value
  
  // step 1: instruct sensor to read echoes
  Wire.beginTransmission(0x10) ; // transmit to device 0x10
  Wire.write(0x5A) ; // some read command.
  Wire.write(0x05) ;
  Wire.write(0x00) ;
  Wire.write(0x01) ;
  Wire.write(0x60) ;
  Wire.endTransmission() ; // stop transmitting
  
  // step 2: wait for readings to happen
  delay(100) ; // datasheet suggests at least 100ms
  
  // step 3: request reading from sensor
  Wire.requestFrom(0x10, 4) ; // request first 4 bytes from slave device #0x10
  Wire.read() ; Wire.read() ; //ignore header bytes
  // remaining two bytes for distance (DIST_L, DIST_H) 
  dist = Wire.read() ; dist += Wire.read() << 8 ; // calculate distance value, bit shift high distance
  return dist ; // return updated dist
}


77833: <p>I need to read the distance data from a lidar in I2C using an Arduino Nano. Currently, this is the code I've written.</p>
<pre><code>unsigned int readDistance()
{
  unsigned int dist = 0 ; // LiDAR actually measured distance value. static so we can return previous dist
  
  // step 1: instruct sensor to read echoes
  Wire.beginTransmission(0x10) ; // transmit to device 0x10
  Wire.write(2) ; // sets distance data address (addr)
  Wire.write(3) ; // sets distance data address (addr)
  Wire.endTransmission() ; // stop transmitting
  
  // step 2: wait for readings to happen
  delay(100) ; // datasheet suggests at least 100ms
  
  // step 3: request reading from sensor
  Wire.requestFrom(0x10, 2) ; // request 2 bytes (DIST_L, DIST_H) from slave device #0x10
  dist = Wire.read() ; dist += Wire.read() &lt;&lt; 8; // calculate distance value, bit shift high distance
  return dist ; // return updated dist
}
</code></pre>
<p>But I have a feeling I'm requesting from the wrong data address', since I'm not getting the results I expect (ie. varying distance data). Furthermore, I used an I2C scanner which 100% confirms the lidar is on the (default address) of 0x10.</p>
<p>Datasheet of (TF02 Pro): <a href="https://www.unmannedtechshop.co.uk/wp-content/uploads/2020/01/TF02-Pro-Product-Manual-Alpha.pdf" rel="nofollow noreferrer">https://www.unmannedtechshop.co.uk/wp-content/uploads/2020/01/TF02-Pro-Product-Manual-Alpha.pdf</a></p>
<p><strong>Question: am i reading from the right data address</strong>
Any help would be appreciated.</p>
 77833: <p>Long story short, some i2c devices are configured such that data is only present in said registers after continually issuing 'read commands'.</p>
<p>In this case, the read command was: 5A 05 00 01 60</p>
<p>Amended code:</p>
<pre><code>unsigned int readDistance()
{
  unsigned int dist = 0 ; // LiDAR actually measured distance value
  
  // step 1: instruct sensor to read echoes
  Wire.beginTransmission(0x10) ; // transmit to device 0x10
  Wire.write(0x5A) ; // some read command.
  Wire.write(0x05) ;
  Wire.write(0x00) ;
  Wire.write(0x01) ;
  Wire.write(0x60) ;
  Wire.endTransmission() ; // stop transmitting
  
  // step 2: wait for readings to happen
  delay(100) ; // datasheet suggests at least 100ms
  
  // step 3: request reading from sensor
  Wire.requestFrom(0x10, 4) ; // request first 4 bytes from slave device #0x10
  Wire.read() ; Wire.read() ; //ignore header bytes
  // remaining two bytes for distance (DIST_L, DIST_H) 
  dist = Wire.read() ; dist += Wire.read() &lt;&lt; 8 ; // calculate distance value, bit shift high distance
  return dist ; // return updated dist
}
</code></pre>
