Public and Highway Lighting is an indispensable component of any society or country. It plays a vital role in ensuring the safety of drivers and pedestrians. It apparently costs around $5000 to $8000 to completely install a street lighting system and it is 20% more for installing a highway lighting system.
Considering the power consumption and maintenance costs, it costs around 200$ for powering a single street light for a year. This would cost millions of dollars to power thousands of street lights for the municipal corporation of a city or state. In such a situation, having a system that strategically saves energy consumption is mandatory for any municipal corporation or country.
What if your lighting system detects the slightest movement of a car from a distance on a road and turns the street light ON? What if your lighting system can measure the lux value of the surroundings and turn the street lights ON instead of simply turning them ON only at a particular time of the day? What if your lighting system is smart enough to understand weather and temperature changes and turns ON accordingly?
This is where our project comes to the rescue. With a unique combination of the Temperature Sensor, Ambient Light Sensor and the PIR Motion Sensor, our IoT based Smart Street Lighting System ensures maximum energy and cost savings. Using our system, more lights can be installed thereby reducing accidents on highways and city streets due to improper or inadequate street lighting. Its adaptive nature ensures that a safe journey is guaranteed to riders under any condition.
What it does
The IoT based Smart Street Lighting System is a compact package built upon the ATSAMW25 to maximize power savings and adapt to different weather conditions.
The system primarily consists of three sensors. This includes: Temperature Sensor, PIR Motion Sensor and Ambient Light Sensor
Motion to detect the entry and exit of a vehicle is monitored by the PIR motion sensor. The weather conditions (fog, mist, winter, rain, summer, etc.) are monitored by the temperature sensor that turns the system ON when the temperature is below 6°C (43°F). The Ambient Light Sensor checks for the luminous intensity of a location to ensure whether the visibility of the surroundings is sufficient enough for drivers and turns the street light ON if the lux value is below 700 (under poor light conditions). The system also consists of repair lights to ensure that during maintenance cycles, the repair lights spring into action while the main light is being serviced.
How it Works
We have worked on this project right from the design development phase till the final deployment. The complete PCB design was performed in Altium Designer and this involved designing and preparing the PCB Schematic, PCB Layout, the Bill of Materials (BOM), the schematic designs and the footprints for all the individual components involved. It uses a low power ATSAMW25 wireless module that consists of a SAMD21 ARM Cortex-M0 microcontroller from Atmel combined with a 2.4GHz ATWINC1500 WiFi chip. Once the design was completed, the corresponding NC Drill and Gerber files were generated. The PCB manufacturing and assembling process was given to a third party vendor, PCBWay while we completely programmed our own customized bootloader for this project.
The SHTC3 Temperature and Humidity sensor used I2C communication and were very accurate in producing highly accurate real-time temperature values. In our system, the temperature sensor on one hand triggers the street light ON if the temperature of the location goes below 6°C which could highlight the presence of rough weather conditions, fog, winter climates, etc.
The Ambient Light Sensor (VEML 6030) measures the lux value of the location. It is found that during the day lux values can go as high as 1000 lux and more for a clear sunny day. We found that lux values below 700 lux are generally associated with overcast and dark conditions going below 700. So, we have kept a threshold of 700 lux below which the Ambient Light Sensor will trigger the street lights ON on detecting a vehicle.
The PIR Motion sensor is tasked with the crucial purpose of detecting the entry and exit of a vehicle at either end of the street light system. Upon detecting the entry of a vehicle and given one or more of the other conditions hold true, the PIR sensor triggers the street light ON and continues this until the exit of the vehicle is detected.
While the SHTC3 is integrated with the PCB, both the PIR and Ambient Light sensor are connected externally and communicate seamlessly with our PCB. The street lights were 3D printed and followed the exact similar shape and orientation of street lights used in reality. We used the help of Detkin Lab Assistant Andrew Katz, for 3D printing the street lights.
Challenges we ran into
One of the major challenges we encountered during our project work was getting the PCB boards fabricated and sent to us in time. Due to the complexity of the boards and the complications involved in transporting them all the way to us, we had less than a week to actually work with the boards and get our desired results. We were instead working on development boards for all the sensors and ATSAMW25.
Another major challenge was the stability of the PIR Motion Sensor. The PIR Motion sensor required about 5-10 seconds to settle down when it was initially started. Following this, after each time it sensed movement, it required about 1-5 seconds to stabilize and be able to detect motion again. (This was a challenge because we had to give it 2 seconds or so for it to settle down and subsequently detect motion. Otherwise, it was fluctuating and turning the street light ON and OFF).
Being new to Free RTOS and Altium Designer, it was a new and challenging experience initially which we later managed to become comfortable at.
Accomplishments that we're proud of
Our compact hardware design provides maximum power savings because the street light would only function when one or more of the conditions are satisfied instead of simply being turned ON when there is no need. We also make use of the MQTT protocol for sending data to the cloud. This allows us to perform Over the Air Firmware Updates (OTAFU) on all the boards in our system.
Our cloud platform is completely reliable and user-friendly such that anyone new to our system can conveniently understand the functioning. When the system goes into maintenance mode, the inter-board communication is smooth and the repair lights take control while the primary street lights are being serviced.
We are happy with how we managed to interface unfamiliar and new components with the ATSAMW25 comfortably and ensure that they worked as expected. As responsible members of the engineering community, we have ensured that the entire code has been written in a manner that makes it easy for anyone new looking into the project to be able to understand it seamlessly. With the support of our friend and Detkin Lab Assistant Andrew Katz, we were able to design and 3D print some dapper looking street lights.
What we learned with the prototype
Over the course of the project, we understood it was a challenge to understand and program the I2C communication between the ATSAMW25 and the I2C sensors (SHTC3 and VEML6030). Being new to working with Free RTOS, we learned to establish smooth communication between the components after multiple attempts. Communicating with the MQTT broker to ensure that the sensor data information is correctly updated on the cloud was also a major challenge from which we learned. Through a careful study, we learned the lux values and general temperature values for which road transportation might become challenging for drivers.
What we learned
We firmly believe that this is the first course where we completely learned and implemented all the different sectors and components of a project from the start till the final deployment. We learned to design a PCB for our specific purpose in Altium Designer. While designing our circuit, we realized the importance of attending to finer details within the datasheet of a component to use the component in the right fashion. We became comfortable with sourcing the required components, preparing the bill of Materials, and adding the footprints and schematics for the same.
We also became aware of how to place orders with PCB vendors, follow up with them over any changes, and confirm the final PCB version that will be sent to us even after submitting the design files (NC Drill and Gerber files). Throughout the development of the project, we learned that keeping a backup at different junctures will prove very helpful.
We got comfortable working with Node-Red and Free RTOS over the course of this project making us confident to continue working on other cool projects.
What's next for Maxi-Luz
Our primary objective moving forward is to further tune the system and be able to control the brightness of the LED. This would ensure more power savings as with carefully tuned efforts, the street light would only be triggered when the real need is there. Depending on the situation and other supporting factors, the brightness can be increased to offer more visibility to drivers or decreased when there is no pressing need for a very bright output.
As another extra addition, we can add a feature wherein which instead of an email notification, a mobile alert is sent to the service station staff to notify them that the street light at that particular location needs to be serviced.