Category Archives: ESP32

Electronics, ESP32, RAD Delphi

DHT22 (Temperature and Humidity) Aggregators

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Been running this circuit and server DHT22 aggregator since May 2022.
Basically this is a client (actually a server – ESP32 REST respond server), and a windows server (that calls the ESP32 server every interval, and aggregates the data into a sqlite3 small db).
Win Server as can be seen on the screen shot, displays compared data of temperature/humidity of the last four days – graph x-temperature y-time_of_day.

Technical details:

  • Win Server is a Delphi VCL Win32 application using TChart for the charts plot.
    In addition I’ve coded that the app taskbar icon, will light in RED when no connection can be made to the defined address.
  • ESP32 chip Server is an espressif-IDF SDK,. C code,. ESP32 is simply connected GPIO to the DHT22 sensor (as can be seen on the chip wired image).
    In addition I’ve connected a red led light, that is turned on, when no connection is done for defined interval to the ESP32 server.
    Calls to the ESP32 server are replied structured in very simple REST JSON record format.
DHT22 Windows server aggregator screenshot
DHT22 ESP32 server aggregator screenshot

Wrote a small app, that takes all my aggregated Temperature data and displays it on a scale of PI per day,. according to the temperature every period of time.
Total 148 days,. total 2.4m records (probed every 5sec – on a sqlite3 db).
It scales from the color red when the temperature was about 24.9c — to the green/black (which is kinda these days) when temperature is about 29c~30c.

Android, Electronics, ESP32, RAD Delphi

First time with electronics! Yey!

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I started playing a little with electronics, for the first time in my life. I keep on being amazed with the wide options it all open for me, breaking the PC to small parts unleash worlds of possibilities. I got into several personal projects — when I immediately saw when these options were revealed.
A good friend of mine introduced me to Autodesk Eagle  — software to draw circuits. In addition you can download and insall Adafruit & Sparkfun electronics huge parts catalog in your Eagle for you to use.
I bought a ESP32 WROOM DevKitC  from Expressif — but couldn’t find the proper Eagle schematics for the ESP32 unit on the web (even after looking for it for a half a day).  There were a lot of links that presented the information in .pdf files. Cause it is very early stage of me playing with Eagle, I couldn’t find a proper way importing the .pdf to Eagle.
So I used the following resources:

And assembled a My Eagle schematics of ESP unit – Download ESP32 DevKitC Eagle Library  Schematics.
Due to the fact it is the first day I am playing with Eagle, there may be issues in the Schematics I assembled, which will be corrected if required.

More information about the different kind of ESP units can be found here.

My DoorBell Project:

My doorBell project is easy to explain,. basically some one rings the bell and a whole process it inititiated:

  • BellRing event is launched (On the ESP unit)
  • Windows Server logs activity (Using Delphi Datasnap WebBroker Technology)
  • Windows Server notify Android end units and a RPiZW unit to play the audio ring (Android units written with Delphi FMX, and RPiZ is a python based script)

An Eagle schematics I made of the ESP32. The big chip in the middle is the ESP32 v4 I am using:

I added in, the Eagle footprint image of the chip as noted:

This is a sample of the unit in action (on a test breadboard — note it is wired differently — it is the first test I made), with all sides modifications — it still requires some modifications and changes:

 

This is are two images of the circuit soldered on a standard prototype board: