Wifi signal strength indication using esp8266

This is a fun project. Rather a very simple project. I am using the RSSI level checking of the esp8266 chip to monitor the signal strength of the surrounding wi-fi signals.

There are very few applications that i can think using this.

  1. You can check where the wi-fi signal is strong in a public place and stand near it to enjoy your free wi-fi more comfortably.
  2. location finding using the signal strength. Well as you go near the object the signal will become stronger and hence location finding device.
  3. You can also use some pretty special algorithm and some positioning mathematics to triangulate the relative position of a particular station.

Code:

AT+CWLAP

This is this simple one line of the code that you need to send to the esp8266 and the esp8266 will transmit the message from where you can use string manipulation to gather the information needed.

 

ESP8266 voltage spikes on power rail

I used esp8266 for broadcasting message to my website. But to operate this chip smoothly one needs to redesign its power supply.

There are voltage spikes of around 320 mV

esp8266 voltage spikes on power rail
esp8266 voltage spikes on power rail

at normal operation the chip uses around 70 mA or current. and when broadcasting something over WiFi current  can rise to about 170mA( according to its datasheet).

This all is not the problem. Because everything works.

Problem is the voltage drop accross the lm317t.

Input voltage = 12v

output voltage = 3.3v

voltage difference = 12v – 3.3v = 8.7v

load current = 105 ma

power dissipating = 8.7V x 0.105A = 0.9135W

That’s a lot of power which is being thermal dissipated.

I used a very tiny heat sink. Also the heat sink is attached by a drop of fevicol instead of thermal paste (cheap solution)

My Suggestion:
use a 5V input at lm317t

volatge difference = 5v – 3.3v = 1.7v

power dissipation = 1.7 x 0.105 = 0.178 W

 

3.3 volt receiver signal level Interface board for esp8266-01

In my previous attempt at designing this board here. It was good. But to make the pcb smaller. I redesigned the pcb, i shifted some component here and there.

This PCB contains a 3.3v level shifter at the receiver pin.

Here are the schematics and pcb layout.

esp8266-01 interface schematics
esp8266-01 interface schematics
drill layout top esp interface
drill layout top esp interface
top silk layer esp interface
top silk layer esp interface
bottom trace esp interface
bottom trace esp interface
Top View of esp8266  interface board
Top View of esp8266 interface board
PCB bottom copper traces and pads
PCB bottom copper traces and pads

Etching time : 1 hour and 20 minutes

That’s very long time but the solution is used up. as this is a small board i don’t want to dip the board in new solution. Also i let the PCB sit for a while , and by doing this the etching is uniform and the i also found out that the traces are much sharper than before. So it is a good idea to let it sit for around 30 minutes before you shake the container. As i am doing this manually, so that is why it is a slow process.

 

Interfacing board of esp8266 to 5V microcontroller

Esp8266 runs on 3.3V and most microcontrollers run on 5v . The voltage difference can cause problems in communication or in the worst case it can burnout the esp8266.  So to address this probelm i created this simple interfacing pcb.

3d rendering of interfacing pcb

Schematics and PCB Layout

Industrial Automation Using Internet of Things

The system will automatically monitor the industrial applications and generate alerts/alarms or take intelligent decisions using concept of IOT. The monitoring and controlling of the industrial automation is done through atmega32 microcontroller. The communication through the internet is done with the help of ESP8266 module. All the sensor data is collected and sent to the web server which processes and analyzes the data and sends a controlling response to the device for control action. The device receives the response and decodes the response message and control the stepper motor. Automation through IoT can help to get rid of the short distance communication.

Project Image
Project Image

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