I want to connect ATtiny85 to ESP-01 and communicate between them using software serial. The problem is ATtiny85 can't send data to the ESP-01.
ATtiny85 uses SoftwareSerial while ESP-01 use the hardware serial both connected at 9600 baudrate
The schematic is shown in the attached image
Please post your full sketch(es).
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ESP sketch
#include <Arduino.h>
#include <FS.h>
#include <ESP8266WiFi.h>
#include <DNSServer.h>
#include <ESP8266WebServer.h>
#include <WiFiManager.h> //https://github.com/tzapu/WiFiManager WiFi Configuration Magic
#include <ArduinoOTA.h>
#include <ArduinoJson.h> //https://github.com/bblanchon/ArduinoJson
#include <ESP8266Ping.h>
#include <ESP8266HTTPClient.h>
#include <base64.h>
#include "EEPROM.h"
// Create an instance of the server
// specify the port to listen on as an argument
WiFiServer server(80);
void handleRequest(WiFiClient client);
void handleResponse(WiFiClient client, String response);
String readSerialResponse();
void connectWiFi() {
WiFiManager wifiManager;
wifiManager.setConfigPortalTimeout(180);
if (!wifiManager.autoConnect("MY_NODE", "MY_PASSWORD")) {
delay(3000);
ESP.reset();
delay(5000);
}
}
void setup() {
Serial.begin(9600);
delay(10);
connectWiFi();
Serial.println("WiFi connected");
server.begin();
Serial.println("Server started");
Serial.println(WiFi.localIP());
}
void loop() {
//check if still connected to wifi
if (WiFi.status() != WL_CONNECTED)
{
Serial.println("Not connected to the Wifi, will try to connect in 5 second");
delay(5000);
connectWiFi();
}
// Check if a client has connected
WiFiClient client = server.available();
if (!client) {
return;
}
// Wait until the client sends some data
Serial.println("new client");
while (!client.available()) {
delay(1);
}
handleRequest(client);
}
void handleRequest(WiFiClient client)
{
String req = client.readStringUntil('\r');
String requestBody;
while (client.available()) {
requestBody += (char)client.read();
}
String response = "";
client.flush();
if (req.indexOf("/alive") != -1)
{
response = sendAliveSignal();
}
else {
Serial.println("invalid request");
client.stop();
return;
}
client.flush();
handleResponse(client, response);
}
void handleResponse(WiFiClient client, String response)
{
String s = response;
client.print(s);
delay(1);
}
String sendAliveSignal() {
Serial.println("<alive>");
return readSerialResponse();
}
#define START_CHAR '<'
#define END_CHAR '>'
String readSerialResponse() {
String response = "";
long start_timestamp = millis();
//wait 2 seconds for serial response
while (Serial.available() <= 0 && abs(millis() - start_timestamp) < 2000) {
delay(10);
}
bool startCharFound = false;
while (Serial.available()) {
char inChar = (char)Serial.read();
if (inChar == END_CHAR) {
break;
}
if (startCharFound)
response += inChar;
delay(2);
if (inChar == START_CHAR) {
startCharFound = true;
}
}
response.trim();
return response;
}
ATtiny85 sketch
#include <Arduino.h>
#include "SoftwareSerial.h"
void tryReadingSerial();
void handleCommand(String command);
#define SIGNAL_PIN 4
#define ESP_RESET_PIN 3
#define SERIAL_TX_PIN 0
#define SERIAL_RX_PIN 1
#define BLINK_PIN 2
SoftwareSerial espSoftwareSerial(SERIAL_RX_PIN, SERIAL_TX_PIN); //(RX,TX)
long esp_timeout_timestamp = 0;
long ESP_TIMEOUT_THRESHOLD = 10 * 60 * 1000; //10 MINUTES
void setup() {
// put your setup code here, to run once:
espSoftwareSerial.begin(9600);
pinMode(SIGNAL_PIN, OUTPUT);
pinMode(ESP_RESET_PIN, OUTPUT);
pinMode(BLINK_PIN, OUTPUT);
digitalWrite(SIGNAL_PIN, HIGH);
digitalWrite(ESP_RESET_PIN, LOW);
digitalWrite(BLINK_PIN, LOW);
}
void loop() {
tryReadingSerial();
if (millis() > esp_timeout_timestamp) { // reset the ESP
if (millis() - esp_timeout_timestamp > ESP_TIMEOUT_THRESHOLD) { // only reset ESP if interval has passed and nothing received from ESP
digitalWrite(ESP_RESET_PIN, HIGH);
delay(10);
digitalWrite(ESP_RESET_PIN, LOW);
}
}
else { //overflow occured
esp_timeout_timestamp = millis();
}
}
#define START_CHAR '<'
#define END_CHAR '>'
void tryReadingSerial() {
String command = "";
bool startCharFound = false;
while (espSoftwareSerial.available()) {
digitalWrite(BLINK_PIN, HIGH);
char inChar = (char)espSoftwareSerial.read();
if (inChar == END_CHAR)
break;
if (startCharFound)
command += inChar;
if (inChar == START_CHAR)
startCharFound = true;
delay(2);
digitalWrite(BLINK_PIN, LOW);
delay(2);
}
command.trim();
if (command != "") {
handleCommand(command);
}
}
void handleCommand(String command) {
if (command == "alive") {
esp_timeout_timestamp = millis();
espSoftwareSerial.println("<Alive signal recieved...>");
}
}
Did you get just the serial communication between the tiny85 and and ESP to work before adding all of the other function?
Have you looked at the techniques in the serial input basics tutorial?