1. Microprocessor Options (Estimated Cost in US Dollars 5)

Option 1: ESP32 Development Kit C 38pin (MyBuild)

Option 2: ESP32 Development Kit C 32U 38pin

Option 3: ESP32 UNO

2. RS232 to TTL

Option 1 ($ 1.5 - 4)

RS232 to TTL Module

+

Gender Changer + Null Modem (if required)

Option 2/3 ($ 0.7 - 1.5)

RS232 to TTL (My Build - SP3232EEN Chip)

OR

RS232 to TTL Module

3. RS232 to TTL ($ 1 - 5)

RJ45 to RS232/Direct Solder (My Build - DIY - Small Length)

OR

RJ45 to RS232 Cable

4. Power Source ($ 2 - 5)

5V 2A Micro USB (My Build - Old Phone Charger)

Optional Hardware

5. Display
Option 1: Matrix Display (Parola / FC16 / Generic / IC - Compaitble)

2x 8x32 RED $9 (My Build - Good Visibility from distance)

5. Display ($ 2 - 5)
Option 2: LCD Display $3-8 (1602 / 1604 / 2002 / 2004 with controller)

LCD - 2004A White on Blue Recoomeded

OR

LCD 1602A (16 = Columns 02 = Rows)

6. Buzzer ($ 1)

5V Buzzer (My Build)

+

100 Ohm Resister needed with Buzzer

7. Micro SD Card Reader Module for Data Logging ($ 1-5)

Microsd Card Adapter Arduino

+

Upto 2GB supported

8. Jumper / PCB wires ($ 1-3)

Not Optional - you need for connections anyways

9. Veroboard Stripboard($ 1-3)

My Build 24x60(Estimated)

10. XH 2.54 90 Degree Connectors ($ 1-5)

4pin LCD, 4pin RS232, 5pin Matrix, 6pin SD

+

I used ready wires

11. PCB Pin/DIP Header ($ 1)

I have used for Micro Controller, TTL Module & Buzzer for easy replacement

12. 3D Printed Casing

No Screw needed other than for wall mounting Download (https://www.thingiverse.com/thing:5025648)

Fits in SIT Cover Download (https://www.thingiverse.com/thing:5025645)

13. Additional ESP32 Micro Controllers & their power source