ESP8266 - Chatbox - Captive Portal

Chatbox enables local communication via Wifi between smartphones and tablets.

• wifi hotspot & captive portal redirect
• for local communication & information
• via smartphone, tablet and notebooks
• during power outage or blackout
• adhoc mesh network & emergency infrastructure

Multiple ESP devices automatically connect to each other to form a mesh network.

How to use

Setup the Chatbox:

• place the Chatbox with visual contact to your neighbors
• a good location is the balcony, window sill, a flagpole or on the roof
• power the Chatbox / ESP8266-chip with a powerbank or by car battery
• with a 20.000 mAh powerbank the chatbox works 10 days
• place multiple Chatboxes every 50m to build a mesh network

Setup the Infopage

• connect to your Chatbox-ABCD via Wifi
• your smartphone open a popup with the homepage
• click OK to navigate to the chat
• click info link to open your infopage
• click change link to edit your infopage
• note useful infos, e.g. water points, frequency for emergency calls, etc.
• use your personal password (cliPwd at firmware) for change

Using the Chat

• every neighbor can connect to the open hotspot
• his smartphone will automatically redirect to the home page
• every user can create a new chat message (optional: sender, receiver)
• the chat message will display at the chat page
• the chat page automaticly reloads after some seconds
• every client will disconnect, if the maximum number of 8 devices is reached
• other clients join to the hotspot to read the chat

How to install

• install Arduino at notebook or ArduinoDroid at Android
• download the source code to your device
• change the cliPwd at the source code
• upload the firmware to ESP8266 device

Recommended ESP8266 devices

• Wemos D1 mini
• NodeMCU

Extend range by additional antenna

Note: if there is no emergency situation you have to reduce AP_POWER

• +5dBm = +50% range by 6cm wire (dipole antenna)
• +9dBm = +100% range by 5× 3cm wire (monopole antenna)

I try diffent antenna hacks to extend the range. The best result I get by solder a wire direct to the antenna lane on the pcb. You need to carefully scrape off the protective varnish.