Introduction: Standalone Intelligent Sensor System

About: We are retired engineers/software developers who enjoy developing projects that are useful and practical. All of our projects are well documented and are published under an open source, non-commercial license.

The Standalone Intelligent Sensor (SIS) is an inexpensive build-it-yourself system that processes information from a variety of passive wireless sensors to create a timestamped log containing meaningful information and inferences about a person’s in-home activities. The SIS log can be securely accessed over the Internet, providing caregivers and concerned relatives a picture of how competently an elderly person living alone is performing the routine activities of daily life.

The initial release of SIS uses wireless proximity infrared (PIR) motion sensors and wireless door separation sensors to log movements of a person around and in/out of their home. Judicious placement of the PIR sensors provides a compact picture of a person’s activities via the natural association of those activities with areas of the home; e.g. bedroom for sleeping and dressing, bathroom for personal hygiene, kitchen for food preparation and living room for relaxation and socialization. The SIS consists of up to 20 inexpensive wireless sensors and a small hub device containing wireless receivers, an advanced microcontroller, and WiFi connectivity. The current release of SIS requires WiFi for connection to the Internet; however, a 3G wireless version is anticipated in the near future. SIS also contains client software that can communicate with the in-home hub over the Internet, via a free cloud service from The client software is written in Javascript and can be hosted on any device that supports a Javascript enabled web browser (desktop, laptop, tablet, smart phone, etc.). Communication between the SIS Hub, the cloud and a client is authenticated and encrypted to ensure privacy and security of the data. SIS is completely open source and all documentation and design files are provided at:

We are interested in expanding SIS beyond the current application to make it into a true open source collaborative platform. Contact us with your comments, thoughts and ideas for additional applications at:

Step 1: Learn About SIS and Decide What You Want to Do.

The first step is to understand fully what SIS is all about and the documentation that we have provided to assist you in ordering parts, building the SIS Hub, installing the firmware, planning your installation, and using the SIS Client app. The starting point is to read the document:

You must also read, understand and accept the Terms of Use, License and Disclosure:

Step 2: Plan Your Installation and Order Your Sensors.

The Theory of Operation and Installation Manual contains all of the information that you need to plan your installation and order the sensors that you will need:

SIS uses inexpensive wireless sensors that you can purchase from E-Bay or for under $10 each. The sensors are battery operated and the batteries should be good for a period of 6 months to several years. The main sensor type used in SIS is the wireless PIR motion sensor (shown above). SIS also uses magnetic separation sensors on exterior doors. Additional sensor types may be used within SIS. These include Water Level Sensors, Vibration Sensors and Keyfobs.

SIS compatible sensors operate in the 315 MHz and 433 MHz RF bands (SIS supports a mix of sensors operating on both frequencies). The modulation is On/Off Keying (OOK) and the sensors transmit codes compatible with the PT2262 and EV1527 protocols. The SIS release package also contains Arduino source code that transmits data that is compatible with SIS. You can use this software to create your own, SIS compatible sensors:

Step 3: Build Your SIS Hub

The SIS Hub receives codes from the SIS wireless sensors, processes these codes into unique sensor trips, meaningful events, and useful inferences, timestamps and logs this information, and makes the log available for secure access over the Internet. The SIS Hub is based upon the Particle Photon module ( You must solder up a PC board to create the Hub. Complete instructions for doing so, including parts list, are contained in the SIS Hub PCB Assembly Instructions manual:

Only basic through-hole soldering skills are required.

After assembling the HUB PCB, you may optionally mount it into a plastic enclosure, following the instructions in:

Finally, you will need to install the firmware into the SIS Hub by following the PCB Firmware Installation instructions:

Step 4: Install and Register Your Sensors

You will next install your sensors and register each sensor into the SIS Hub using the instructions found in the Theory of Operation and Installation Manual:

The sensors are small and battery operated. They are easily installed using screws or double sided tape. They are wireless, so there are no wires to run.

As you install each sensor, you must register it to SIS using the SIS Client app software. This software will run on any device that has a javascript-enabled web browser, including smartphones, tablets and laptops. Follow the instructions in the Theory of Operation and Installation Manual to run this software to register each of your sensors, so that only your sensors will be processed by SIS and so that the SIS log contains useful and easily identifiable sensor information.

Step 5: You Are Ready!

Your SIS is installed and ready for you to monitor an elderly persons activities from anywhere in the world. Complete information can be found in the SIS Users Manual:

Enjoy using your SIS. Let us know how your construction, installation and operation went. Use our compete open source information to make your own improvements to SIS and please share them with us and with the world. Let us know how you are using SIS and what improvements you would like us to make. We are eager to hear from you:


Bob and Jim

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