What is it?

1. Embedded

Hardware

+

// __attribute__((OS_main)) tells the compiler that this function never
// returns and saves us precious space
__attribute__((OS_main)) int main(void) {

    hal_init(&comm_byte_received_callback);

    // This is the main handling loop
    // It handles all packets that can arrive in the Normal mode
    while (1) {
        if (comm_wait_for_packet(&p[current_packet]) == 0) {
            switch (p[current_packet].id) {
                case packet_GET_STATUS:
                    sendACK();
                    break;
                case packet_RFID_SEND:
                    // We will send data from this packet, and replace them
                    // in-place with what we receive
                    hal_spi_begin_transaction();
                    for (uint8_t i = 0; i < p[current_packet].length; i++) {
                        p[current_packet].data[i] =
                            hal_spi_transfer(p[current_packet].data[i]);
                    }
                    hal_spi_end_transaction();
                    // And suddenly, we are a response packet :)
                    p[current_packet].id = packet_RFID_SEND_COMPLETE;
                    transmit_and_flip();
                    break;
                case packet_RX_ERROR:
                    // Retransmit the last packet
                    comm_transmit_packet(&p[current_packet ^ 1]);
                    break;
                default:
                    // Unacceptable packet was received in this mode
                    p[current_packet].id = packet_INVALID_PACKET;
                    p[current_packet].length = 0;
                    transmit_and_flip();
                    break;

Software

2. Server:

Centralized Management

• access database
• logs / monitoring
  • access
  • system state
• firmware updates

3. UI:

Interface for Humans

• easy access management
  • ~10k people
  • ~100 doors
  • time of day, day of week, etc.

=> needs to be done well!

• also: logs, system state

We already have that!

How?

Server

• "One server to rule them all"
• access database: card ID => when can I open which door?
• distributes data to door controllers
• auxiliary functions:
  • centralized logs storage
  • firmware updates

Controller

• controls a single door
  • "should I open now?"
  • door sensor (was it opened without permission?)
• ​should work offline
  • ​so that we don't care about server/connection problems
• custom embedded device
  • (optional) Power over Ethernet (standard)
  • ARM Cortex M0 MCU
  • software in C (+ ChibiOS)

Server ↔ Controller

• standard Ethernet
• Power over Ethernet
• communication over UDP
• encryption, authentication

Reader

• Číta ISIC-y
• Bliká a pípa :)
• Komunikuje buď cez naše rozhranie alebo
  cez USB
• ARM Cortex M0 MCU
• Naprogramovaný v C (+ ChibiOS)

Controller ↔ Reader

• custom interface
• simple installation, available
• power + data
• based on RS-232

How much better is this?

Price

Open source &

Open hardware

Practical installation & administration

Future-proof