Answers.Body: <p>It is not a protocol limitation. It is a sensor limitation. There is a microcontroller on the LEGO EV3 Ultrasonic sensor that cannot be updated so there is no way to measure more than that. So to measure more than 255cm, a 3rd party sensor is needed, e.g. <a href="https://mindsensors.com" rel="nofollow noreferrer">https://mindsensors.com</a>.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-28T10:55:28.473Z
Answers.Text: Well can I manually tell the sensor to send a pulse?
Answers.UserDisplayName: he77789
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Answers.CreationDate: 2019-10-28T15:43:23.750Z
Answers.Text: I'm not sure what you mean, but there is an "Advanced" mode of the sensor that takes a single reading instead of measuring continuously. This mode is intended to prevent multiple ultrasonic sensors from interfering with each other.
Answers.UserDisplayName: David Lechner
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Answers.CreationDate: 2019-10-28T23:49:51.157Z
Answers.Text: As distancing is just measuring the time between the emitted pulse and reflected pulse, can we use the main EV3 brick to emulate the on board weaker chip?
Answers.UserDisplayName: he77789
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Answers.CreationDate: 2019-10-29T01:06:04.547Z
Answers.Text: No, that is not possible.
Answers.UserDisplayName: David Lechner
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-29T16:04:58.250Z
Answers.Text: @he77789 According to the EV3 Hardware Development Kit, the ultrasonic sensor has a small 8-bit controller inside which communicates over UART with the EV3. This is probably where the limitation of 255cm comes from: 8-bits cannot represent numbers larger than 255. And since the controller is physically between the EV3 and the sensor hardware, the EV3 can't ping the sensor manually.
Answers.UserDisplayName: MindS1
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Answers.CreationDate: 2019-10-30T23:40:15.163Z
Answers.Text: Well there is a "listen" mode. This means the controller can have multiple modes. Is there a list of commands or something similar to check if you can tell the controller to send a pulse?
Answers.UserDisplayName: he77789
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-31T15:45:20.100Z
Answers.Text: http://docs.ev3dev.org/projects/lego-linux-drivers/en/ev3dev-stretch/sensor_data.html#lego-ev3-us
Answers.UserDisplayName: David Lechner
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Answers.CreationDate: 2019-10-27T19:30:41.810Z
Answers.LastActivityDate: 2019-10-27T19:30:41.810Z
Answers.UserDisplayName: David Lechner
Body: <p>In my use case, I have to detect things about 3-4 meters. I don't need to be accurate, +-2 or 3cm is enough. The EV3-G and most other places have a max distance of 255cm, which I understand that it is a protocol limitation.</p>
  
  <p>But is there a software solution, e.g. controlling send/receive with software and calculate on the main brick? Best if it is in the form of EV3-G custom blocks.</p>
  
Tags: <ev3><piece-information><programming><ev3-g>
Title: Detect distances over 255cm with EV3 ultrasonic sensor?
UserDisplayName: he77789
ThreadText: # Detect distances over 255cm with EV3 ultrasonic sensor?
  
  (Asked by: username_0 on 2019-10-27)
  
  In my use case, I have to detect things about 3-4 meters. I don't need to be accurate, +-2 or 3cm is enough. The EV3-G and most other places have a max distance of 255cm, which I understand that it is a protocol limitation.
  
  But is there a software solution, e.g. controlling send/receive with software and calculate on the main brick? Best if it is in the form of EV3-G custom blocks.
  
  **Tags:** ev3, piece-information, programming, ev3-g
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2019-10-27. Score: 3
  
  It is not a protocol limitation. It is a sensor limitation. There is a microcontroller on the LEGO EV3 Ultrasonic sensor that cannot be updated so there is no way to measure more than that. So to measure more than 255cm, a 3rd party sensor is needed, e.g. <https://mindsensors.com>.
  
  > **Comments:**
  > **username_0**: Well can I manually tell the sensor to send a pulse?  
  > **username_1**: I'm not sure what you mean, but there is an "Advanced" mode of the sensor that takes a single reading instead of measuring continuously. This mode is intended to prevent multiple ultrasonic sensors from interfering with each other.  
  > **username_0**: As distancing is just measuring the time between the emitted pulse and reflected pulse, can we use the main EV3 brick to emulate the on board weaker chip?  
  > **username_1**: No, that is not possible.  
  > **username_2**: @username_0 According to the EV3 Hardware Development Kit, the ultrasonic sensor has a small 8-bit controller inside which communicates over UART with the EV3. This is probably where the limitation of 255cm comes from: 8-bits cannot represent numbers larger than 255. And since the controller is physically between the EV3 and the sensor hardware, the EV3 can't ping the sensor manually.  
  > **username_0**: Well there is a "listen" mode. This means the controller can have multiple modes. Is there a list of commands or something similar to check if you can tell the controller to send a pulse?  
  > **username_1**: http://docs.ev3dev.org/projects/lego-linux-drivers/en/ev3dev-stretch/sensor_data.html#lego-ev3-us  
  
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