Environment Sensing BLE Dev Board for Energy Efficient IoT Devices

January 27, 2020 by Paul Shepard

Ricoh Electronic Devices Co., Ltd. has launched the RIoT-001, an environment sensing board usable in demonstration experiments of IoT devices. The RIoT-001 is an environment sensing board which monitors ambient temperature, humidity, air pressure, and brightness.

The information the RIoT-001 transmits with its Bluetooth Low Energy (BLE) once per five seconds can be displayed on smartphones or tablets where an application programmed for the RIoT-001 is installed.

The RIOT-001 contains Ricoh's ultra-low supply current and low noise power management ICs and achieves independent power generation, prolongation of battery operating time, and high accuracy, which IoT edge devices require. The new sensing board can make it easy to develop new IoT edge devices and contributes to shortening the construction period of those devices.

You may also like: Semtech Releases New LoRa Smart Home Device for IoT Applications

RIoT-001 block diagram (click on image to enlarge)

Charging from Solar Battery to Secondary Battery

The R1800, a buck dc-dc converter for energy harvesting, extracts electric power from a solar battery. The converter has a maximum power point control function to configure a voltage at which the solar battery can produce its maximum power, and therefore optimizes the amount of power generation of the solar battery.

In addition, a reverse current protection prevents charging loss. These multiple functions in the R1800 enables the RIoT-001 to derive electric power from a solar battery with high efficiency.

High-efficiency Operation

The RP604, a buck-boost dc-dc converter with ultra-low supply current, supplies electricity for an MCU, BLE, and sensors, which contributes to achieving a high-efficiency operation at both standby and active modes. The wide operating voltage from 1.8V to 5.5V also enables the board to make efficient use of the secondary battery power.

The RP604 is highly popular for its easy-to-use design featuring ultra-low supply current, high efficiency, and stable output voltage regardless of input fluctuations.

Battery Monitoring with Low Power Consumption

One of the conventional ways of monitoring secondary battery voltage is to input divided voltage to the ADC of an MCU by using resistor dividers. However, this circuit structure enlarges supply current of the board. Instead, by using the RP124, an LDO regulator including a battery monitor, a low supply current battery voltage monitoring function can be constructed with ease.

Maintenance-free Operation

As the secondary battery, the board is equipped with the SLB series (SLB03070LR35) manufactured by Nichicon Corporation. When fully charged, the secondary battery can continue to operate for approximately 20 hours (A theoretical value).

The RIoT-C01, a coin battery board for the RIoT-001

The RIoT-C01 is a coin battery board designed for RIoT-001. By using a CR2032-type battery, the RIoT-001 can continue its sensing operation for 1 year and a half (a theoretical value).

Before using the RIoT-001, the secondary battery on it must be charged because the battery is not charged at all when you get the board. The RIoT-C01 can omit the time to wait for the battery to be charged and therefore let you use the RIoT-001 as soon as you get it. It is easy to connect the two boards thanks to a pair of connectors mounted on them.