Affordable energy autonomous wireless sensor for day and night

Bluetooth Smart is enabling a new class of sensors where device configuration and data presentation can be done using smart phones, tablets, personal computers and even smart watches. Sensors are equipped with a wireless link that allows them to transfer data to other devices or to get information from them. This opens up many applications with high volume potential. The promise of a large market has led to an abundance of Bluetooth Smart solutions, which is a good thing for the consumer. Competition will lead to improved quality and will drive costs down. But there is also the danger of a maintenance nightmare, if questions such as energy consumption and security are not properly addressed. Sensors need a power source and the way this is often done is to use batteries. They are small and low cost. But maintenance of sensors powered by small batteries means finding them (if one can still remember where they are) and changing the batteries. This is both resource consuming and ecologically expensive. Energy harvesting can help bring the needed autonomy, reduce and even eliminate the maintenance issues as far as energy is concerned. So far however, energy harvesting has proved expensive. In this work, we use a new power management system to design a sensor that runs day and night on energy harvested using a very small solar cell.  Part of the energy harvested when there is enough light is stored for use at night. On-the-fly change of the measurement rate allows an optimal management of the energy. We succeeded in designing and building a system with a cost effective solar cell, which can run day and night on harvested energy

Harvesting energy from trees in order to power LPWAN IoT nodes

Low Power Wide Area Network (aka LPWAN or LPWA or LPN) nodes are important components in the IoT chain. They allow energy-efficient wireless communications between elements that can be several kilometers apart. This in turn should enable energy savings and facilitate the deployment of energy autonomous devices. However, energy autonomy is still in its infancy, as far as LPWAN is concerned. Most nodes run on mains or batteries. Mains seriously limit the mobility of the nodes and are only used in special cases. Batteries often lead to maintenance costs issues. Scavenging energy from the surroundings to achieve energy autonomy is an alternative that has hardly been used for LPWAN systems. In cases where energy harvesting has been used, solar energy has been the most popular source. Other methods are possible and could even be important alternatives. In this work we harvest energy from trees using TEGs. That energy is stored and used to power a long-range wireless embedded system (LoRaWAN in this case). Tests made for several months have shown that this method works well. Enough energy is harvested in all seasons, allowing sensing and transmission of data several times per day

Traffic analyzer front-end for complex IEEE 802.15.4 applications

The last years have seen a proliferation of the use of wireless communication in different applications. The systems range from simple 2-nodes communication to complex mesh systems capable of covering vast areas. Debugging such systems, especially large mesh networks can be a daunting task. There are few tools that can help. In this paper, we present and discuss the results of a monitoring tool we are developing. The system is modular, based on a deterministic multicore processor. In the proof of concept, each monitoring probe is equipped with several IEEE802.15.4 transceivers, making it possible to monitor several wireless channels at the same time and to implement a mitigation of diversity issues in the monitoring. The transceivers could also be used to generate test frames for the system under test if necessary. The parallel architecture makes it easy to add new modules and to synchronize the sniffers with the most appropriate methods. In this phase of the work, we used DCF77 to synchronize the nodes. The collected data is sent to a common host for analysis with appropriate tools. The results show that the architecture is appropriate and that synchronization should be improved

Low light energy autonomous LoRaWAN node

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A LoRaWAN node powered using an 8 cm2 solar cell was designed and its low light harvesting performance evaluated. The embedded system is used to sense some parameters and transmit the results every 10 minutes, using the spreading factor SF7BW125 and transmitting with + 8 dBm, which allows the coverage of a small building. The node can cold start with less than 30 lux. Once started, its operations can be sustained down to 20 lux. Operation at higher spreading factors or higher RF output power is also possible if the transmission interval is increased. Such a performance enables the use of energy autonomous LPWAN nodes in poorly lit environments. The small size of the solar cell makes it possible to build small nodes

Unten Standard – oben proprietär : eine Übersicht über verschiedene Embedded-Wireless-Technologien – Beitrag 6/6

Der Bluetooth Low Energy Solar Tag – kurz Blens Tag – ist ein Beispiel, bei dem die Entwickler die proprietären Eigenschaften des Systems erst in höheren Schichten eingeführt haben. Sie haben vorhandene Schaltungen verwendet und so von den niedrigen Kosten und der Herstellervielfalt der ICs profitiert. Die vom Standard abweichenden Eigenschaften betreffen hauptsächlich Änderungen in der Software