Infineon Technologies AG is collaborating with e-peas to validate and prototype the design of an ambient-powered Bluetooth remote control

Ambient-Powered Bluetooth Remote Control

The basic idea behind the ambient-powered remote control design (omitting ambient-powered from here on for simplicity) is to integrate three key components that leverage core technologies and expertise from each collaborating partner in the project: An indoor light solar cell from Ambient Photonics, an ambient energy management IC from e-Peas, and an ultra-low power Bluetooth^® MCU from Infineon. Figure 1 shows the high-level system diagram of the design.

Indoor Light Solar Cell

Indoor light is captured with a low-light indoor (LLI) bi-facial photovoltaic (PV) cell based on patented, dye-sensitized solar cell technology from Ambient Photonics that enables ambient energy harvesting in an efficient manner. These cells produce three times more power than traditional Si-based solar cells, and their higher power density is optimal for low-drain applications like remote controls. With such an energy source, there is no need for a battery chamber which makes the remote sleek, small, and lightweight.

Ambient Energy Manager IC

The energy captured with the solar cell is transformed and supplied to the remote control unit by the AEM00940 ambient energy manager IC from e-peas. The AEM00940 is targeted to harvest energy from PV sources having a fixed voltage range over the lighting range, meaning that the impedance of the source is quasi proportional to the light level. With a single PV element, the AEM00940 starts working from a low voltage level and boosts it to the storage element with high efficiency, reaching and generating a regulated output of 3V to power up the rest of the system. The AEM00940 provides protection against under- and over-voltage situations, ensuring that the storage element operates in safe conditions.

The supply source architecture stores several joules of energy to support application requirements. The supply source is provided with a level of pre-charge that allows the AEM00940 to cold start the first time. Once started, the AEM00940 performs continuous charging of the storage element.

Bluetooth Low Energy MCU

Control, computing, and wireless communication functions in the system are enabled by the CYW20829 Bluetooth^® MCU from Infineon. The CYW20829 is a high-performance, ultra-low power, and secure MCU compliant with the latest version (v5.4) of the Bluetooth Core Specification. It is optimal for Bluetooth LE HID applications like remotes and keyboards.

The CYW20829 is configured to remain in deep-sleep power mode most of the time to minimize energy consumption. The application runs on freeRTOS with multiple tasks handling Bluetooth, KeyScan, and battery monitoring. The Bluetooth task initializes the stack, GATT DB, and starts the advertisement service. The KeyScan task detects the key event, such as press/release, maps it to the HID report map, and sends it to the TV via a Bluetooth notification. The battery monitoring task is used to monitor battery voltage periodically and calculate battery life.

Design Prototype

To validate the concept, mechanical and functional prototypes of the design have been built. Figure 2 shows the remote control PCB with the Bluetooth^® MCU and required external components. The full remote control prototype encased in its plastics can be seen in Figure 3. For testing, the remote control was paired to an Android TV, and the functions outlined in Figure 4 were checked.

The functionality of the design has been verified and debugged in the lab. To showcase the results, a working demo of the project was presented at Infineon’s 2023 OktoberTech™ tradeshow in Silicon Valley.

What’s Next?

Ambient IoT is relevant, attractive, and practical. With Bluetooth^® LE at the core, it has enormous potential to drive new applications and use cases, commercial success, sustainability in the smart home, and decarbonization. To accelerate the ramp up and adoption of Ambient IoT, partnerships and collaborations to leverage technologies and expertise will be key, as evidenced by the project presented in this article. Look forward to seeing conventional remote controls replaced by ambient-powered Bluetooth remote control solutions very soon!