{"id":3698,"date":"2025-05-10T17:02:20","date_gmt":"2025-05-10T17:02:20","guid":{"rendered":"https:\/\/iotthinghub.com\/?p=3698"},"modified":"2025-05-10T17:38:42","modified_gmt":"2025-05-10T17:38:42","slug":"controlling-multiple-load-using-simple-esp01-in-softap","status":"publish","type":"post","link":"https:\/\/iotthinghub.com\/?p=3698","title":{"rendered":"Controlling Multiple load using Simple esp01 in softAP"},"content":{"rendered":"\n

In this article we control multiple loads using single esp01 module. Before starting let\u2019s have some review. In our ESP8266 as a SoftAP mode (AT Command Mode)<\/a> article we use esp01 working as a command mode & STM32 as a core microcontroller. ESP01 can properly handle all the function as a core so no need for an external microcontroller. Here we use either PCF8574 or PCF8574A for load control, since it is an I2<\/sup>C device, we can control as many as load we wanted.  Let\u2019s begin with simple 3 steps- Step 1: The PCF8574A is an I2<\/sup>C parallel port expander with latch outputs with high-current drive capability for directly driving LEDs.<\/p>\n\n\n\n

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If we connect A0<\/sub>, A1<\/sub>, A2 <\/sub>pin to ground the default address will be 0b00100000 or 0x20. Chose either PCF8574A or PCF8574. Let\u2019s you don\u2019t know the I2<\/sup>C address & start from getting the I2<\/sup>C address. Connect GPIO2 to SCL & GPIO0 to SDA of the I2<\/sup>C device & before connecting, load the following program to the esp01 chip with GPIO0 to Ground connection. Remember for programming the esp01 you have to connect GPIO0 to GND thus enter esp01 into programming mode.<\/p>\n\n\n

\n#include <Wire.h>\nvoid setup() {\n  Serial.begin(115200);\n  Wire.begin(0, 2); \/\/ GPIO0 = SDA, GPIO2 = SCL\n  Serial.println("Scanning I2C devices...");\n}\n\nvoid loop() {\n  for (byte address = 1; address < 127; address++) {\n    Wire.beginTransmission(address);\n    if (Wire.endTransmission() == 0) {\n      Serial.print("Device found at 0x");\n      Serial.println(address, HEX);\n    }\n  }\n  delay(10000);\n}\n<\/pre><\/div>\n\n\n
It is a very simple program to find out the I2<\/sup>C address of your IC device. Step2 : In first step you get the I2<\/sup>C address, assume it 0x20. In this step let\u2019s see if it working or not. We sequentially turn Pin-P0, and then Pin-P1, then Pin-P2 & Pin-P4 and the process continues. Connect 4 LED\u2019s & check the following program-<\/p>\n\n\n
\n#include <Wire.h>\n#define PCF8574_ADDR 0x20  \/\/ Default I2C address of PCF8574\nvoid setup() {\n  Wire.begin(0, 2); \/\/ GPIO0 = SDA, GPIO2 = SCL\n}\n\nvoid loop() {\n  Wire.beginTransmission(PCF8574_ADDR);\n  Wire.write(0b00000001);  \/\/ Turn ON first pin (P0)\n  Wire.endTransmission();\n  delay(1000);\n  Wire.beginTransmission(PCF8574_ADDR);\n  Wire.write(0b00000010);  \/\/ Turn ON second pin (P1)\n  Wire.endTransmission();\n  delay(1000);\n  Wire.beginTransmission(PCF8574_ADDR);\n  Wire.write(0b00000100);  \/\/ Turn ON third pin (P2)\n  Wire.endTransmission();\n  delay(1000);\n  Wire.beginTransmission(PCF8574_ADDR);\n  Wire.write(0b00001000);  \/\/ Turn ON forth pin (P3)\n  Wire.endTransmission();\n  delay(1000);\n}\n<\/pre><\/div>\n\n\n
Step 3: In STM32 we enter softAP mode by AT command mode. Here we use Arduino platform. The default APIP is 192.168.4.1, but it can be changed. ESP01 only support class C IP address. A Class C IP address is a part of the IPv4 address classification system that was originally used to define network sizes. Address Range: 192.0.0.0 to 223.255.255.255 with Default Subnet Mask 255.255.255.0. Let\u2019s use IP: 192.168.10.7, Gateway IP: 192.168.10.7 & Sub Netmask: 255.255.255.0 as-<\/p>\n\n\n
\n#include <ESP8266WiFi.h>\n#include <ESP8266WebServer.h>\nconst char* ssid = "IoTthingHuB";    \/\/ provide any SSID Name\nconst char* password = "Test123456"; \/\/ provide any SSID Password\nWiFiServer server(80);               \/\/ Server port 80  \nIPAddress local_ip(192,168,10,7);    \/\/ Provide Class C IP\nIPAddress gateway(192,168,10,7);     \/\/ Provide Class C GateWay\nIPAddress subnet(255,255,255,0);     \/\/ Default SubNet (Not Changable)\nWiFi.softAP(ssid, password);         \/\/ Creating Soft Access Point\nWiFi.softAPConfig(local_ip,gateway,subnet);\nSerial.println("Access Point Started!");\nserver.begin();\n<\/pre><\/div>\n\n\n
HTML code will be same as STM32 article with change of 4 Load to Control.<\/p>\n\n\n\n
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  • HTML code: Off condition<\/li>\n<\/ul>\n\n\n\n
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    \n<!DOCTYPE html> <html>\n<head><meta name=\\"viewport\\" content=\\"width=device-width, initial-scale=1.0, user-scalable=no\\">\n<title>Load Control<\/title>\n<style>html { font-family: ZCOOL XiaoWei; display: inline-block; margin: 2px auto; text-align: center;}body{margin-top: 40px;}\nh1 {color: #0e18f3;margin: 45px auto 25px;}\nh3 {color: #050505;margin-bottom: 40px;}\n.button {display: block;width: 60px;background-color: #b589f0;border: none;color: white;padding: 15px 25px;text-decoration: none;font-size: 20px;margin: 0px auto 30px;cursor: pointer;border-radius: 5px;}\n.button-on {background-color: #b589f0;}\n.button-on:active {background-color: #2fd4e0;}\n.button-off {background-color: #65537a;}\n.button-off:active {background-color: #2fd4e0;}\n p {font-size: 16px;color:#040404;margin-bottom: 12px;}\n<\/style><\/head><body><h1>Simple Web Server<\/h1>\n<h3> IoT ThingHuB <\/h3>\n<p>LOAD 1 Status: OFF<\/p><a class=\\"button button-on\\" href=\\"\/LED1on\\">ON<\/a>\n<p>LOAD 2 Status: OFF<\/p><a class=\\"button button-on\\" href=\\"\/LED2on\\">ON<\/a>\n<p>LOAD 3 Status: OFF<\/p><a class=\\"button button-on\\" href=\\"\/LED3on\\">ON<\/a>\n<p>LOAD 4 Status: OFF<\/p><a class=\\"button button-on\\" href=\\"\/LED3on\\">ON<\/a>\n<\/body>\n<\/html>\n<\/pre><\/div><\/div>\n\n\n\n
    \n \n\nLoad Control<\/title>\n<style>html { font-family: ZCOOL XiaoWei; display: inline-block; margin: 2px auto; text-align: center;}body{margin-top: 40px;}\nh1 {color: #0e18f3;margin: 45px auto 25px;}\nh3 {color: #050505;margin-bottom: 40px;}\n.button {display: block;width: 60px;background-color: #b589f0;border: none;color: white;padding: 15px 25px;text-decoration: none;font-size: 20px;margin: 0px auto 30px;cursor: pointer;border-radius: 5px;}\n.button-on {background-color: #b589f0;}\n.button-on:active {background-color: #2fd4e0;}\n.button-off {background-color: #65537a;}\n.button-off:active {background-color: #2fd4e0;}\n p {font-size: 16px;color:#040404;margin-bottom: 12px;}\n<\/style><\/head><body><h1>Simple Web Server<\/h1>\n<h3> IoT ThingHuB <\/h3>\n<p>LOAD 1 Status: OFF<\/p><a class=\\\"button button-on\\\" href=\\\"\/LED1on\\\">ON<\/a>\n<p>LOAD 2 Status: OFF<\/p><a class=\\\"button button-on\\\" href=\\\"\/LED2on\\\">ON<\/a>\n<p>LOAD 3 Status: OFF<\/p><a class=\\\"button button-on\\\" href=\\\"\/LED3on\\\">ON<\/a>\n<p>LOAD 4 Status: OFF<\/p><a class=\\\"button button-on\\\" href=\\\"\/LED3on\\\">ON<\/a>\n<\/body>\n<\/html>\n\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><\/div>\n<\/div>\n\n\n\n<p class=\"has-text-color has-link-color wp-elements-0c179a7f00622a303b6fac271e3ac8c5 wp-block-paragraph\" style=\"color:#252525\">HTML code: On condition<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-7387b849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:33.33%\">\n<!DOCTYPE html> <html>\n<head><meta name=\\\"viewport\\\" content=\\\"width=device-width, initial-scale=1.0, user-scalable=no\\\">\n<title>Load Control<\/title>\n<style>html { font-family: ZCOOL XiaoWei; display: inline-block; margin: 2px auto; text-align: center;}body{margin-top: 40px;}\nh1 {color: #0e18f3;margin: 45px auto 25px;}\nh3 {color: #050505;margin-bottom: 40px;}\n.button {display: block;width: 60px;background-color: #b589f0;border: none;color: white;padding: 15px 25px;text-decoration: none;font-size: 20px;margin: 0px auto 30px;cursor: pointer;border-radius: 5px;}\n.button-on {background-color: #b589f0;}\n.button-on:active {background-color: #2fd4e0;}\n.button-off {background-color: #65537a;}\n.button-off:active {background-color: #2fd4e0;}\n p {font-size: 16px;color:#040404;margin-bottom: 12px;}\n<\/style><\/head><body><h1>Simple Web Server<\/h1>\n<h3> IoT ThingHuB <\/h3>\n<p>LOAD 1 Status: ON<\/p><a class=\\\"button button-off\\\" href=\\\"\/LED1off\\\">OFF<\/a>\n<p>LOAD 2 Status: ON<\/p><a class=\\\"button button-off\\\" href=\\\"\/LED2off\\\">OFF<\/a>\n<p>LOAD 3 Status: ON<\/p><a class=\\\"button button-off\\\" href=\\\"\/LED3off\\\">OFF<\/a>\n<p>LOAD 4 Status: ON<\/p><a class=\\\"button button-off\\\" href=\\\"\/LED4off\\\">OFF<\/a>\n<\/body>\n\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:66.66%\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: xml; auto-links: false; title: ; quick-code: false; notranslate\" title=\"\">\n<!DOCTYPE html> <html>\n<head><meta name=\\"viewport\\" content=\\"width=device-width, initial-scale=1.0, user-scalable=no\\">\n<title>Load Control<\/title>\n<style>html { font-family: ZCOOL XiaoWei; display: inline-block; margin: 2px auto; text-align: center;}body{margin-top: 40px;}\nh1 {color: #0e18f3;margin: 45px auto 25px;}\nh3 {color: #050505;margin-bottom: 40px;}\n.button {display: block;width: 60px;background-color: #b589f0;border: none;color: white;padding: 15px 25px;text-decoration: none;font-size: 20px;margin: 0px auto 30px;cursor: pointer;border-radius: 5px;}\n.button-on {background-color: #b589f0;}\n.button-on:active {background-color: #2fd4e0;}\n.button-off {background-color: #65537a;}\n.button-off:active {background-color: #2fd4e0;}\n p {font-size: 16px;color:#040404;margin-bottom: 12px;}\n<\/style><\/head><body><h1>Simple Web Server<\/h1>\n<h3> IoT ThingHuB <\/h3>\n<p>LOAD 1 Status: ON<\/p><a class=\\"button button-off\\" href=\\"\/LED1off\\">OFF<\/a>\n<p>LOAD 2 Status: ON<\/p><a class=\\"button button-off\\" href=\\"\/LED2off\\">OFF<\/a>\n<p>LOAD 3 Status: ON<\/p><a class=\\"button button-off\\" href=\\"\/LED3off\\">OFF<\/a>\n<p>LOAD 4 Status: ON<\/p><a class=\\"button button-off\\" href=\\"\/LED4off\\">OFF<\/a>\n<\/body>\n\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"517\" src=\"https:\/\/iotthinghub.com\/wp-content\/uploads\/2025\/05\/ESP-01-Project-2-1024x517.jpg\" alt=\"\" class=\"wp-image-3722\" srcset=\"https:\/\/iotthinghub.com\/wp-content\/uploads\/2025\/05\/ESP-01-Project-2-1024x517.jpg 1024w, https:\/\/iotthinghub.com\/wp-content\/uploads\/2025\/05\/ESP-01-Project-2-300x152.jpg 300w, https:\/\/iotthinghub.com\/wp-content\/uploads\/2025\/05\/ESP-01-Project-2-768x388.jpg 768w, https:\/\/iotthinghub.com\/wp-content\/uploads\/2025\/05\/ESP-01-Project-2.jpg 1152w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-7387b849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<div class=\"wp-block-buttons is-content-justification-center is-layout-flex wp-container-core-buttons-is-layout-3e41869c wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/iotthinghub.com\/wp-content\/uploads\/2025\/05\/Scanner.rar\" target=\"_blank\" rel=\"noreferrer noopener\">I<sup>2<\/sup>C Scanner<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/iotthinghub.com\/wp-content\/uploads\/2025\/05\/Scanner.rar\" target=\"_blank\" rel=\"noreferrer noopener\">I<sup>2<\/sup>C Scanner.zip<\/a><\/p>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-7387b849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<div class=\"wp-block-buttons is-content-justification-center is-layout-flex wp-container-core-buttons-is-layout-3e41869c wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/iotthinghub.com\/wp-content\/uploads\/2025\/05\/PCF8574_TesT.rar\" target=\"_blank\" rel=\"noreferrer noopener\">I<sup>2<\/sup>C PCF8574<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/iotthinghub.com\/wp-content\/uploads\/2025\/05\/PCF8574_TesT.rar\" target=\"_blank\" rel=\"noreferrer noopener\">I<sup>2<\/sup>C PCF8574.zip<\/a><\/p>\n<\/div>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe title=\"esp01: Controlling Multiple load using Simple esp01 in softAP \ud83d\udcf1 PCF8574(I2C Scanner)\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/iO2BkjHk_Ks?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>In this article we control multiple loads using single esp01 module. Before starting let\u2019s have some review. In our ESP8266 as a SoftAP mode (AT Command Mode) article we use esp01 working as a command mode & STM32 as a core microcontroller. ESP01 can properly handle all the function as a core so no need […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[],"class_list":["post-3698","post","type-post","status-publish","format-standard","hentry","category-esp01esp8266"],"_links":{"self":[{"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/posts\/3698","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3698"}],"version-history":[{"count":18,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/posts\/3698\/revisions"}],"predecessor-version":[{"id":3729,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/posts\/3698\/revisions\/3729"}],"wp:attachment":[{"href":"https:\/\/iotthinghub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3698"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3698"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3698"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}