C Ingestion SDK

The C Ingestion SDK is a portable header-only library written in C99 for data collection on embedded devices. It's designed to reliably store sampled data from sensors at a high frequency in very little memory. On top of this it allows cryptographic signing of the data when sampling is complete. Data can be stored on a POSIX file system, in memory, or on a raw block device.

Installation instructions

• Add Mbed TLS to your project (see signing contexts to use a different TLS library).

• Download the SDK.

• Copy the inc folder to your project. This contains all headers and source files.

Usage

The following application:

• Initializes the library.

• Sets up the Mbed TLS signing context with the key my-hmac-sha256-key.

• Creates a file with three axes (accX, accY, accZ) and four readings.

• It then prints out the CBOR buffer.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "sensor_aq.h"
#include "sensor_aq_mbedtls_hs256.h"
  
int main() {
  // context to sign data, this object is instantiated below
  sensor_aq_signing_ctx_t signing_ctx;
  
  // use HMAC-SHA256 signatures, signed with Mbed TLS
  sensor_aq_mbedtls_hs256_ctx_t hs_ctx;
  // initialize the Mbed TLS context which also instantiates signing_ctx
  sensor_aq_init_mbedtls_hs256_context(&signing_ctx, &hs_ctx, "my-hmac-sha256-key");