Control your Nextion display using a esp8266 and mqtt
This sketch uses a esp8266 and mqtt to control a Nextion Display which is conected to serial pins 13,15 of the ESP. ESP lolin Pinout (https://www.aerial.net/shop/imageslarge/IOT-AMICA_pinout.jpg) ESP Pins 13,15 can be used for serial2 communication . Ardiono UNO pins 2,3 will be used to connect to display.
The sketch publishers every event that is fired from the display to a mqtt channel which is defined under the root_topicOut
It allows for setting text and sending commands to the display through the root_topicIn subscribed mqtt channel.
The two topics that have been exposed for control are "setComponentText" and "sendCommand". eg: to set text for a txt control on the display just send the following payload
{ "topic":"setComponentText", "payload":{ "component":"page0.t2", "text":"hello" } }
to Set a background picture send { "topic":sendCommand, "payload":{ "command":"page0.b0.picc=1" } }
Dont forget to change MQTT_MAX_PACKET_SIZE 128 to 256 in file pubsubclient.h if you want to use Large texts in MQTT.
You will also need this library https://github.com/bborncr/nextion (thanks for this bborncr)
You can also use Node-red to set different texts and commands. example:
[{"id":"a909d4ea.be9478","type":"mqtt in","z":"a1a84f55.f6dbe","name":"","topic":"Nextion/Out","qos":"2","broker":"d4be06bc.5dd008","x":153,"y":204,"wires":[["6aa28447.9e3eec","51353c01.ca0d54"]]},{"id":"b8f0d5ef.fc4768","type":"function","z":"a1a84f55.f6dbe","name":"","func":"var settemp = flow.get("settemp");\nnode.warn(settemp);\nsettemp = settemp + 0.5;\nif (settemp >= 30)\n{\n settemp=30;\n}\nflow.set("settemp",settemp);\n\nmsg.payload=settemp.toFixed(1) ;\nmsg.topic="setComponentText"\nreturn msg;","outputs":1,"noerr":0,"x":543,"y":177,"wires":[["a09e256d.815e18","e403a4cb.763e18"]]},{"id":"51353c01.ca0d54","type":"switch","z":"a1a84f55.f6dbe","name":"","property":"payload","propertyType":"msg","rules":[{"t":"eq","v":"65110ff","vt":"str"},{"t":"eq","v":"65120ff","vt":"str"}],"checkall":"true","outputs":2,"x":348,"y":202,"wires":[["b8f0d5ef.fc4768"],["b00ca382.40cb4"]]},{"id":"e403a4cb.763e18","type":"template","z":"a1a84f55.f6dbe","name":"Command Template","field":"payload","fieldType":"msg","format":"handlebars","syntax":"mustache","template":"{\n"topic":{{topic}},\n"payload":{\n "component":"Thermostat.t2",\n "text":"{{payload}}"\n }\n}","x":837,"y":205,"wires":[["4ec90d5f.6956a4"]]},{"id":"4ec90d5f.6956a4","type":"mqtt out","z":"a1a84f55.f6dbe","name":"","topic":"Nextion/In","qos":"","retain":"","broker":"d4be06bc.5dd008","x":1165,"y":155,"wires":[]},{"id":"b00ca382.40cb4","type":"function","z":"a1a84f55.f6dbe","name":"","func":"var settemp = flow.get("settemp");\nnode.warn(settemp);\nsettemp = settemp - 0.5;\nif (settemp <= 10)\n{\n settemp=10;\n}\nflow.set("settemp",settemp);\n\nmsg.payload=settemp.toFixed(1) ;\nmsg.topic="setComponentText"\nreturn msg;","outputs":1,"noerr":0,"x":538,"y":242,"wires":[["e403a4cb.763e18"]]},{"id":"d4be06bc.5dd008","type":"mqtt-broker","z":"","broker":"192.168.2.231","port":"1883","clientid":"","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]