What is the ASCII code an ultrasonic sensor will output?

Click For Summary

Discussion Overview

The discussion revolves around the output format of the MB7380 ultrasonic sensor, specifically regarding the ASCII code it generates for measured distances. Participants explore the nature of the output, its representation, and how to interpret it in the context of programming and data communication.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions how to convert a distance measurement (0.15 meters) into an 8-bit representation, indicating uncertainty about the sensor's output format.
  • Another participant expresses doubt that the output is in ASCII, suggesting it is likely an 8-bit representation of a distance unit.
  • A later reply clarifies that the output is an ASCII capital "R" followed by four ASCII character digits representing the range in millimeters, but the interpretation of this output is still unclear to some participants.
  • One participant mentions having trouble understanding the conversion of the carriage return character "\r" into its ASCII value, indicating a gap in knowledge about ASCII encoding.
  • Another participant acknowledges their mistake in not reviewing the datasheet linked by the original poster, which contains relevant information about the output format.
  • A participant indicates they received partial help from another forum and plans to share a complete solution involving Arduino programming to emulate the sensor's output.
  • Code snippets are shared that demonstrate how to format the output for distances in a program, but the logic settings of the datalogger are noted as a variable that affects the displayed distances.

Areas of Agreement / Disagreement

Participants express differing views on whether the output is ASCII or a binary representation, with some clarifying the ASCII nature of the output while others remain uncertain. The discussion includes both agreement on the importance of the datasheet and disagreement on the interpretation of the output format.

Contextual Notes

Some participants exhibit gaps in understanding ASCII encoding and the specifics of the sensor's output, which may affect their interpretations. The conversation also reflects varying levels of familiarity with the datasheet and programming practices related to the sensor.

adamaero
Messages
109
Reaction score
1
Problem statement
For an ultrasonic sensor (MB7380) sending 8 data BITS, no parity and one stop bit, what is the ASCII code it will give for a certain distance like 0.15 meters (0.5')?


Attempt at a solution
  • I do not know how to convert 0.15 meters into 8 bits. It is using TTL serial output. I believe this model is the 5' version.
  • I'm thinking I need to borrow a scope from my uni.
  • ASCII Encoder/ Decoder (tool)
 
Physics news on Phys.org
I seriously doubt that the output is in ASCII. It is probably an 8 bit representation of some dustance unit of measure.
 
  • Like
Likes   Reactions: phinds
FactChecker said:
I seriously doubt that the output is in ASCII. It is probably an 8 bit representation of some dustance unit of measure.
Yep. @adamaero you really need to look at the spec sheet for the device.

Also, you clearly don't understand what "ASCII code" means or you would not have asked the question, so you might want to study up on that as well if you are interested in computer communication.
 
"The output is an ASCII capital “R”, followed by four ASCII character digits representing the range in millimeters." Talk about reading the datasheet!

I had trouble interpreting how to convert that. For example, I did not know that "\r" would be 13 in ASCII. (I would've taken both characters separately.) But I was actually helped on a different forum. Thanks, but no thanks.
 
adamaero said:
"The output is an ASCII capital “R”, followed by four ASCII character digits representing the range in millimeters." Talk about reading the datasheet!
Would have been nice if you had said so in the first place. The clear implication of your question was that it was a binary 8-bit output as FactChecker suggested.

But you are correct about the spec sheet. You linked to it and I didn't look at that link. My bad.
 
Last edited:
  • Like
Likes   Reactions: adamaero
adamaero said:
But I was actually helped on a different forum.
Why did you mark your thread Solved here before you got any replies? Is it because you got a reply on a different forum? You didn't reply to my personal message to you about it before any replies appeared in this thread... Just curious.
 
Because with the partial help of another forum, I was going to post the complete solution to what I am doing (i.e., writing an Arduino program to emulate this sensor) . . .
 
Nice! :smile:
 
C: 
void setup() {

  Serial.begin(9600); // bps ~ baud rate
  delay(50);
}

void loop() {
    Serial.write("R0030");  // 30 mm = 1.2" = 0.1'
    Serial.write('\r');     // "\r" (stop bit) carriage return
      delay(60000);         // takes a minute to show on graph
   
    Serial.write("R0061");  // 0.2 feet
    Serial.write(0x0d);     // hex
      delay(60000);
    Serial.write("R0091");  // 0.3 feet
    Serial.write(13);       // ASCII
      delay(60000);
    Serial.write("R0122");  // 0.4 feet
    Serial.write(13);
      delay(60000);
    Serial.write("R0152");  // 0.5 feet
    Serial.write(13);
      delay(60000);
    Serial.write("R0183");  // 0.6 feet
    Serial.write(13);
      delay(60000);
    Serial.write("R0213");  // 0.7 feet
    Serial.write(13);
    Serial.end();
}

And from there it depends on the datalogger's logic settings for the correct distances to be displayed...
 
Last edited:

Similar threads

TTL, voltage, one-wire test rig
  • · Replies 34 ·
2
Replies
34
Views
5K