Optimizing timed operations in a C-based IoT system for real-time data processing
I'm trying to implement Currently developing an IoT application that interacts with sensors and actuators using C in a resource-constrained environment... The scenario involves collecting sensor data at 1-second intervals and processing this data for real-time analytics. However, I've noticed that my timed operations occasionally lag or miss their scheduled execution. I’ve implemented a simple timer using the `clock()` function from `time.h`, but the accuracy is inconsistent across different runs. Here’s a snippet of the timer implementation that I’m currently using: ```c #include <stdio.h> #include <time.h> void read_sensor() { // Simulating sensor reading printf("Sensor data read at %ld\n", time(NULL)); } void start_timer() { clock_t start_time = clock(); while (1) { if ((clock() - start_time) * 1000 / CLOCKS_PER_SEC >= 1000) { // 1000 ms read_sensor(); start_time = clock(); } } } ``` To improve on this, I attempted using the POSIX `nanosleep()` function to yield more accurate timing, but I’m still facing drift, especially when the CPU is under load. Here’s how I integrated that: ```c #include <time.h> void start_timer() { struct timespec req = {0}; req.tv_sec = 0; req.tv_nsec = 100000000; // 100 milliseconds while (1) { read_sensor(); nanosleep(&req, NULL); } } ``` Despite these adjustments, the drift continues, and I’m concerned about the implications for real-time data collection. I’ve looked into using hardware timers available on the microcontroller, but I’m unsure how to set them up correctly without impacting other system functions. Are there best practices or design patterns specifically suited for accurately handling timed operations in C for embedded systems? Would utilizing a real-time operating system (RTOS) be advantageous in this context? Any insights or suggestions would be greatly appreciated. What's the best practice here?