How to Optimize Power Consumption of IoT Devices
Perfecting the optimal power consumption approach in IoT devices is never just one variable, it is a series of processes that designers, developers, and users follow to increase the lifespan and reliability of an IoT Device.
You have to ask: is the device moving around or fixed in one place? What kind of data is it sensing and sharing? And how often? Partially there are multiple options available to optimize power consumption and increase power-saving performance: Hardware energy optimization, Network optimization, Software energy optimization, and energy harvesting. Let’s understand how we bring it together.
Hardware energy optimization
As a device designer, you want to select an energy-efficient Microcontroller Unit (MCU) for IoT applications. The computational requirements may compel you to go for 8-bit or a 32-bit MCU but make sure to keep energy requirement as a significant parameter for selection. Plus, a microcontroller is not the only part that can be an energy hog in your hardware design. Another key to minimizing power consumption is ensuring the use of low-power sensors and nodes. The design of the sensor can contribute heavily to how much power is drawn from the devices. Besides the active components, examine battery type and passive components that can have leakage currents.
Recommendation
- Select an MCU with different speeds and types of timers and clocks to give you many ways to adjust the battery drain
- Where possible, disable power to unused RAM
- Minimize the number of internal peripherals and disable unused peripherals
- Use wide power supply traces on your circuit board
- Use high-efficiency switching regulators rather than linear low-dropout regulators
Network optimization
Choosing a connectivity solution for your IoT device has serious consequences on the choice of the components of your application, the performance of the connected object, and its energy consumption. Low power consumption IoT applications requirements have driven the emergence of LPWAN (LoRaWAN, LTE-M, and NB-IoT) for long-distance connectivity and BLE for battery-powered IoT devices that need short-to-medium communication ranges (Table 1). The distance between two nodes, topology, the data rate, and the message size all influence the transmission time, which impacts power consumption.
Recommendation
- Ensure your device’s transmission frequency accuracy is as tight as reasonably possible
- Don’t Infringe on Your neighbour’s Bandwidth and comply with Relevant Standards
- Ensure your device only transmits when it has useful data
Table 1: IoT Network Connectivity Portfolio
Optimizing software for low energy consumption
Programming your device in low-power and active modes will make a significant difference in conserving battery power. New developments in low power management have launched a wide range of ultra-low-power sleep modes that provide more acceptable levels of granularity beyond just run or idle modes- standby, doze, sleep, and deep sleep, etc. Program your application to spend as little time as possible in the MCU’s “active” mode. It might mean simplifying calculations, batching operations, or transitioning to an asynchronous and interrupt-driven design.
Recommendation
- Increase the amount of time your device spends in low-power sleep states
- Increase clock speed to finish processing faster and use low-power timers for wake-up
- Efficient coding to ensure applications are not performing unneeded tasks
- Consider the effect of firmware choices and updates
- Avoid excessive push notifications
- Smart Monitoring and predictive maintenance
Energy harvesting
Energy harvesting can provide a potentially inexhaustible electrical energy supply captured from the ambient environment. This energy can supplement or replace a primary cell or battery, depending on the application and available ambient energy. You can utilise the harvested energy to power the circuitry directly or store it in a buffer until it is needed. A harvesting design has three sub-functions in addition to the source transducer itself: the circuit that extracts the energy from the transducer, the energy-storage element (battery or supercapacitor), and the harvesting-management circuit, which controls the flow of energy into the battery and the flow of electrons as power out of the battery. (Figure 2)
