Simple sketch for bitmap printing without library compatible with Arduino/ESP8266/ESP32
NO LIBRARY image printing for standard ESC/POS printer also known as EPSON script. This sketch is using just standard Arduino.h library and raw commands described by ESC/POS® Command Reference https://reference.epson-biz.com/modules/ref_escpos/index.php?content_id=2
Some printers like SparkFun or AdaFruit thermal printers are using newer commands which should not work on older ESP/POS printers. This is reason why libraries doesnt work for all printers. This sketch is written for GSerial GP-5890XIII but it should be compatible with all ESC/POS printers as it is using only standart and some obsolete commands.
Wiring is simple just connect RX and TX lines between ESP and printer
Example of using MQTT protocol for printer control and sending data. This sketch was used in combination with simple questionaire created in node-red dashboard. Once form is filled and submited, datas are stored in local .json and .csv files. Simultantously Name and Surname are posted using MQTT into broker and received by printer After that label with advert containing Name and surname is printed.
If you want to use your own logo or QR bitmap you can use very simple SW created by Radosław Kwiecień called LCD Assistant. http://en.radzio.dxp.pl/bitmap_converter/
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.
Some parts of WiFi and MQTT stuff are copied from PubSubClient.h library example distribued under MIT license Source: https://github.com/knolleary/pubsubclient