A Sunlight Reactive Grow Lamp

DJ22016 - Connected Objects

Brief

1. Working in teams of three, you will create a pair or group of connected objects that explore how connected objects could influence our understanding of the natural world. Your challenge is to design and make a working Internet of Things (IoT) prototype product that monitors, senses, or evaluates the natural environment, empowering citizens to adapt, co-design, or enable NbS in their communities.

Our Project

As a team, we developed a grow lamp with a sunlight sensor for people struggling with inadequate natural light for plant growth. The lamp automatically activates when the sun rises in an area similar to the plant's native growing conditions, ensuring plants receive the necessary illumination to thrive.

Supplies

Electronics

1. 2x Wemos D1 mini's
2. 1 Grove sunlight sensor
3. 1 12-bit neopixel ring
4. 1 potentiometer
5. Miscellaneous wires
6. Micro USB to USB-C

Lamp

1. 2mm MDF
2. Clear frosted acrylic

Our first port of call was to build a simpler version of our project using a photoresistor light sensor and just plain LEDs to make sure our idea was going to work over IoT and MQTT. It was also relatively simple as we had very similar code that we were given that we just needed to change numbers in. This also allowed us to get our point across to during our interim presentations allowing us to build and adapt our ideas from the feedback given.

Next, with a final plan decided on, we went ahead and incorporated the final sensors and outputs—a sunlight sensor and Neo pixels. Once the libraries had been downloaded, adding these pieces was relatively hassle-free.

The first thing we tackled was getting the sunlight sensor to publish data to MQTT. The sensor gave you two types of data—an IR value and a visible light value. For ease on the subscribing end, we made the two pieces of data part of a string, allowing them to publish as one piece of data.

Creating the hardware was very simple, as it just involved the Wemos and one other part—the sunlight sensor. The only problem we encountered was the connecter for the sunlight sensor was a grove connection, which did not plug into the wemos easily, so I had to add a few additional wires to make the connection.

We then did the subscribe and output end; this was slightly more complicated as we added in a potentiometer that acted sort of like a button that could switch between sets of data; this included a constant and the changing MQTT data. We also had to add in a string splitter so the IR and visible light data were read as two pieces of information. We originally were going to use an actual grow light, but after talking to Ali, we realised that for the timeline and skills we had, that wasn't achievable. However, we could get a similar look by using Neopixels and setting them to a purple colour. Whi ch was determined by the IR and visible light values from the sensor. The IR value influenced the red colour and the Visible light value influenced the blue colour.

Adding in the potentiometer was slightly complicated because it involved if statements that we hadn't used before, but once we had one working, getting the rest working was relatively repetitive, just adding in 'else if' statements with some thresholds was all that was needed.

Building the hardware was again slightly trickier for this end as it involved some soldering to the Neopixels, then adding in the potentiometer after meant having to re-solder as I needed two connections into the ground pin and 5v pin. I had to ask Ali for some help on the best way to do this.

The next step was constructing the housing for these two pieces - the lamp and the sensor housing. For the lamp, we decided we wanted it to have a wood look, originally we were going to 3d print and then paint it, but we then realised we needed the wires to go through the lamp arm, so we would have to print in sections, we think this would have looked and felt a bit too flimsy for what we wanted. So we decided to laser cut the pieces instead, if we had more time, I think I would have tried to go down to the workshop and tried to make it out of hardwood.

The sensor housing was a bit easier as it was essentially just a box, so we decided to 3d print this part as it needs to be water-resistant as it has to be placed outside, and the simple shape allows for a relatively simple and quick print.