我在玩 Arduino（Uno rev 3）和热敏打印机（此型号https://www.sparkfun.com/products/10438）时玩得很开心。Arduino 每 10 秒向我的本地机器（通过以太网屏蔽）发出一个请求，并将响应（如果 200）存储在 SD 卡上。然后它使用这个库https://github.com/adafruit/Adafruit-Thermal-Printer-Library打印出来。
到目前为止，我已经正确地轮询、存储和打印基本文本，但现在我正在尝试使用一些更高级的命令（下划线、反向等）。我的最终目标是发送图像并在服务器 ala http://printer.gofreerange.com/上处理所有渲染。
问题是我发送的命令被输出为文本字符。一些命令有效（换行），但其他命令是乱码。我已经附上了 Arduino 代码和它调用的基本 PHP 脚本。有什么帮助吗？
阿杜诺：
#include <SPI.h>
#include <Ethernet.h>
#include <SD.h>
#include <SoftwareSerial.h>
#include "Adafruit_Thermal.h"
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
const char host[] = "192.168.1.100";
char cacheFilename[] = "TMP";
const byte printer_RX_Pin = 8; // this is the green wire
const byte printer_TX_Pin = 9; // this is the yellow wire
const byte SD_Pin = 4; // the SD Card SPI pin
bool downloadWaiting = false;
bool statusOk = false;
unsigned long content_length = 0;
EthernetClient client;
Adafruit_Thermal printer(printer_RX_Pin, printer_TX_Pin);
void die(unsigned int times) {
while(true);
}
void checkForDownload() {
Serial.println("checkForDownload");
content_length = 0;
statusOk = false;
unsigned long length = 0;
if (SD.exists(cacheFilename)) {
if (!SD.remove(cacheFilename)) {
die(4);
}
}
File cache = SD.open(cacheFilename, FILE_WRITE);
if(client.connect(host, 80)) {
client.println("GET /printer.php HTTP/1.1");
client.print("Host: "); client.println(host);
client.println("User-Agent: arduino-ethernet");
client.println("Connection: close");
client.println();
bool parsingHeader = true;
while(client.connected()) {
while(client.available()) {
if (parsingHeader) {
client.find((char*)"HTTP/1.1 ");
char statusCode[] = "000";
client.readBytes(statusCode, 3);
statusOk = (strcmp(statusCode, "200") == 0);
client.find((char*)"Content-Length: ");
char c;
while (isdigit(c = client.read())) {
content_length = (content_length * 10) + (c - '0');
}
client.find((char*)"\n\r\n");
parsingHeader = false;
} else {
if(length < content_length) {
cache.write((byte)client.read());
length++;
} else {
client.read();
}
}
}
}
client.stop();
cache.seek(0);
if (statusOk && content_length > 0 && (content_length == length) && (content_length == cache.size())) {
downloadWaiting = true;
}
} else {
client.stop();
}
cache.close();
}
void printFromDownload() {
Serial.println("printFromDownload");
File cache = SD.open(cacheFilename);
byte b;
while (content_length--) {
printer.write((byte)cache.read());
}
printer.feed();
cache.close();
downloadWaiting = false;
}
void setup(){
pinMode(SD_Pin, OUTPUT);
if (!SD.begin(SD_Pin)) {
die(2);
}
if (Ethernet.begin(mac) == 0) {
die(3);
}
Serial.begin(9600);
printer.begin(255);
delay(1000);
}
void loop() {
if (downloadWaiting) {
printFromDownload();
delay(5000);
} else {
checkForDownload();
if (!downloadWaiting) {
delay(10000);
}
}
}
PHP：
<?php
ob_start();
// Turn on Inverse mode
// Doesn't work
echo pack('S', 29);
echo pack('S', 66);
echo pack('S', 1);
$string = 'Testing 1, 2, 3';
foreach(str_split($string) as $char) {
echo pack('S', ord($char)); // works
}
// Turn off Inverse mode
echo pack('S', 29);
echo pack('S', 66);
echo pack('S', 0);
// Line feed
echo pack('S', 10); // works
$content = ob_get_clean();
$length = strlen($content);
header("Content-Length: $length");
echo $content;