UTF-8 / ASCII encoding/decoding [Solved]

General
1

Hi there,

Does the Photon support transmission of the 256 different characters in UTF-8 or the 128 characters in ASCII?Iff so, how is it decoded once received?

Thank you.

2

That depends how you want to transmit.
Binary transport will, … well …, send all bytes as they come, but some functions like Particle.publish() will only be able to send a subset of bytes.

3

Seems to work for me. Here’s the code I ran:

#include "Particle.h"

int funcTest(String arg);
void subHandler(const char *event, const char *data);


String varTest("jalape\u00F1o 100\u03A9 \u30C4");

void setup() {
	Serial.begin(9600);

	Particle.variable("varTest", varTest);
	Particle.function("funcTest", funcTest);
	Particle.subscribe("testSubReq", subHandler);


	Particle.publish("testPub", varTest, PRIVATE);
}

void loop() {
}

int funcTest(String arg) {
	Particle.publish("testFunc", arg, PRIVATE);

	return 0;
}

void subHandler(const char *event, const char *data) {
	Particle.publish("testSubResp", data, PRIVATE);
}

Here’s a picture of the Event Log in the console:

I was also able to send and receive UTF-8 characters from the Particle CLI, at least from the Mac Terminal program.

1 Like
4

Thanks for your response,

I am more in need of a way to transmit information to the Particle P1. We need to transmit 384 bits per transmission, but are limited to 63 characters per transmission. Therefore we would need 7 bits or 128 unique characters. UTF-8 and ASCII are both viable (UTF-8 is preferred), but we weren’t able to transmit data to the Particle with them, as some of the characters did not transmit (the null character and the %). How were you able to get UTF-8 to transmit to Particle?

5

In other words, is there 128 or 256 unique characters which can be sent to the Particle?

6

Sending binary is an entirely different problem. You can’t do that. You’ll have to omit some of the low control characters (at least 0x00 and probably some others), and UTF-8 reserves almost all high-bit set codes for 2, 3, and 4 byte Unicode sequences. The only safe transport for binary data is somewhere around ASCII-85 encoding (4 8-bit bytes in 5 characters).

2 Likes
7

Thank you! Base85 / ASCII85 works.

1 Like
8

Thanks @ScruffR @rickkas7 for helping out!