Raspberry Pi 4B - Alarm system

Raspberry Pi 4B - Alarm system with Spring boot, PI4J and Thymeleaf. The advantage of using Java is that it provides a mature multi-threading library and the powerful spring boot framework that makes this simple project versatile as it can be used both offline via the provided keypad or remote via a web browser.

Dipole RF Calculator

Calculates Ez field from a half-wave dipole antenna at distance r.
Calculates VOC (V open circuit) and Pload from the incident field Ez on an identical receiving dipole antenna at distance r.
Calculates Prx (power received to a perfectly matched load) via Friis formula.

Other features

Displays dipole length from input frequency for a quick antenna design.
Displays dipole feed current Ia from input power.
Converts both Tx and Rx power to dbm for a quick link budget design.
Calculates the free space path loss for a quick link budget design. (this includes both Tx and Rx 2.15db gain)
Computed results are displayed in engineering format.

Spring Boot Integration SFTP

Use Spring Boot with Spring Integration to download and process a remote SFTP file. Automatically reconnect and retry in case of network failure.
Recovery from catastrophic or processing failure via local file storage and Transaction Manager.
Send any errors from errorChannel to the provided health-check via Spring Actuator.
Health-check is secured via Spring Security.
Testing is done via an embedded Apache Mina sshd server.
Docker project for SFTP server is provided to simulate a Production environment.

Secured Text 2 File

Secure store any text to an AES256 encrypted zip file.
Can be used as a password manager.
This little program has the advantage that it extracts and display the content of the encrypted file in his little frame without the need to use an external text editor.

Spring Boot MongoDB embedded

This project is an example of using Spring Boot with MongoDB but more particular testing is done using an embedded MongoDB instance instead of docker.
It includes a simple data model and repository.