[Demo] NNEPS: Network-Updated E-Paper Signage with Reduced Standby Power Consumption Takafumi Akiba and Tsubasa Yumura Hokkaido Information University 1

Introduction • Electronic paper signage (EPS) is a type of digital signage that specializes in displaying still images. • Using EPS, which is updated via the network, the computer controlling the e-paper continuously consumes power while waiting for content and cannot fully leverage the features of e-paper. 3 E-paper E-link Solar Powered 13.3inch Display | AVLink Digital Signage https://www.lcdhome.live/product/e- paper-e-link-solar-powered-13-3inch- display/ Digital Signages Company in Abu Dhabi | Thrive Advertising https://thrive- adv.com/digital-signages/

Proposed Method • In existing network-updated EPS, the display control PC is always running and consumes power • In the proposed method, when updating content, the control PC starts up upon receiving a notification, and the control PC turns off when the e-paper display update is complete. • We named the system that realizes the proposed method, Normally-off Network Electronic Paper Signage (NNEPS). 4 OFF ON ON ON ON OFF Proposed Method （NNEPS） Existing Method （Network-updated EPS） Updated content E-Paper Control PC E-Paper Display Updated content E-Paper Control PC E-Paper Display

System Configuration • The NNEPS is composed of an e-paper, an e-paper control PC, and a power control plug. • The power control plug stands by with the communication function turned on and turns the power supply to the e-paper control PC on and off as needed for screen updates, thereby enabling the EPS to achieve normally-off. 5

Electronic Paper Control Computer Content Transmission 6 Power Control Computer Power Cable Content Management Server Relay Module Electronic Paper Control Computer Electronic Paper SPI connection Startup Command Content Transmission Startup Completion Notification Update Completion Notification Startup Completion Notification Update Completion Notification Update Completion Notification NNEPS Electronic Paper SPI connection System Flow 4. Update Completion Notification 4. Update Completion Notification 4. Update Completion Notification 3. Content Transmission 3. Content Transmission 1. Startup Command 2. Startup Completion Notification 2. Startup Completion Notification Update Image Update Image

Implementation • Power Control Plug consists of M5Stack for AWS (Amazon Web Services) and a relay module • The M5Stack Core2 for AWS was used as the micro-controller that controlled the relay modules. • The M5Stack implements firmware that turns the relay module on and off in response to notifications via MQTT (Message Queuing Telemetry Transport). • Multiple EPSs can be connected using relay modules to manage power on/off status. 7

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Comparison of Existing and Proposed Methods 9 Proposed method (NNEPS) • Total power consumption of e-paper control computer and power control computer • Starts only when the screen is refreshed Existing method (network-updated EPS) • E-paper control computer is always running • Receive content and update images Measure the power consumption of the existing method (network update EPS) and the proposed method (NNEPS) Updated content ON ON ON E-Paper Control PC E-Paper Display Updated content OFF ON OFF E-Paper Control PC E-Paper Display

Evaluation Environment 10 Experimental Conditions • Operating Time: 1 hour • Update Frequency: Every 5 minutes Comparison of Existing and Proposed Methods • Existing Method • 1 device • Proposed Method • Two patterns: connecting 1 or 2 EPS devices to the relay module • 1 device connected: NNEPS-1 • 2 devices connected: NNEPS-2

Assessment of power reduction • Under these conditions, the proposed method, NNEPS-1, reduced the amount of electricity by about 33% compared to the existing method. 11 2.81 1.25 1.88 • The NNEPS measured power for two different cases, one with one EPS connected to the relay module (NNEPS-1) and the other with two EPSs connected to the relay module (NNEPS-2).

Assessment of power reduction 12 • In NNEPS-2, the values were more than double those of NNEPS-1. • In NNEPS-2, the power shutdown occurs only after both e-paper control PCs have completed the refresh process, resulting in increased power consumption due to the extended startup time for both e-paper control PCs. Power consumption during screen refresh Power consumption Power consumption Second Second

Conclusion • In this study, we confirmed that the proposed method is more effective in reducing power consumption than existing methods. 13 Acknowledgments • This research was supported by the Hokkaido IT Creator Discovery and Development Project (Shinsetsu Program) conducted by Shinsetsu, a general incorporated association. We would like to express our sincere appreciation.