Build a Plant Monitoring Prototype Like a Pro (and for Under 100 Dollars)

The first prototype isn’t pretty – first prototypes seldom are – but it does do the trick

A kick-ass demo is essential for every new product. For connected products, a demo is perhaps even more important because connected products break new ground.

Today we’re going to build a prototype of a connected plant monitor for under 100 dollars. It will take only a few minutes to assemble.

Unlike a typical Arduino-style prototype, our prototype has full data history and smartphone app integration from the start, thanks to the Thingsquare IoT platform.

The prototype won’t be as pretty as its original idea, but it will be an actual demo to show to early customers and investors and get that initial traction before even producing a single unit.


The Idea

The plant monitor design, made with Tinkercad

The idea is simple: we solve the problem of killing flowers. Everybody likes flowers, but tend to kill them by forgetting to give them water. If we can solve this problem, there is the potential for making a lot of money.

The solution: a soil moisture sensor, slightly reminiscent of Weedle the Pokémon, that you place in the soil. And a smartphone app that connects to the soil moisture sensor.

To create an initial concept design, we use the free online tool Tinkercad. The result is on the right.

With the Thingsquare platform, we already have an app that we can use for our prototype. All we need to do is to put together the hardware.

The Concept

The app in the hands of a user. Mockup made with Placeit.

The plant monitor should be accessible anywhere our users go, not just when they are near their plants.

First, we need that bunch of early, excited customers. And, most likely, a bunch of early, equally excited, investors to get that money needed to produce the product.

To get people excited, we need a demo. A working demo is much more powerful than mere concepts and ideas.

The Prototype

To build the prototype, we are going to use a $30 wireless prototyping device called a CC1310 Launchpad by Texas Instruments, a $5 soil moisture sensor, and three so-called jumper cables, which can be bought at $4.50 for a 10 pack.

A TI CC1310 Launchpad

A soil moisture sensor

At the heart of the Launchpad is a really small $4 radio chip called CC1310. The pins on the side of the board are connected to, and controlled by, this chip. We are going to connect the sensor to one of those pins, and instruct the radio chip to read the data from the sensor, and post it to our app.

After connecting the sensor to the Launchpad, we have something that looks like this:

A TI CC1310 Launchpad with the sensor connected to it

Again, this isn’t pretty, but it gets the job done.

The cables should be connected like this:

  • From the pin on the sensor marked VCC to the pin on the board marked 3V3
  • From the pin on the sensor marked GND to the pin on the board marked GND
  • From the pin on the sensor marked SIG to the pin on the board marked DIO23

Next up, we need to load the software onto the chip. This is not needed if you have a Thingsquare starter kit, but if you bought a separate Launchpad board, you need to download the Thingsquare client to the board. Instructions for programming the chip can be found here.

After downloading the software, keep the the Launchpad connected to USB power. The red LED should blink to indicate that the board is waiting to be connected to a gateway.

Don’t insert the soil sensor into the flower pot just yet. We need to connect it to the gateway first.

The Gateway

Now we need to connect the plan monitor to the Internet so we can check on our plant even when we’re not near it.

To connect, we need a gateway that lets the radio chip on the Launchpad talk to the Internet. If you have a Thingsquare starter kit, a Weptech gateway is already included. But if you’re building this from scratch, we’ll build a gateway our of another Launchpad board.

To build the gateway, we need a second $30 Launchpad module, a $16 Ethernet module, and six more of those jumper cables. These are a little trickier to connect, but instructions for what cable goes where can be found here. Again, we need to upload the right software to the chip – the link has instructions for how to do that too.

Our self-built gateway

Plug a USB cable with power to the gateway and an Ethernet cable from the gateway to your WiFi router. The red LED on the gateway should blink for a few seconds. When the blinking stops, the gateway is up and running.

Connect

Now the hardware is running and ready to roll. Install the Thingsquare device viewer app, available for iOS and Android, on your smartphone. Make sure the smartphone is on the same WiFi as the gateway.

We are going to connect the sensor and the gateway. Place the Launchpad with the sensor close to the gateway and open the Thingsquare app. Tap the Network button and the gateway should appear. You may need to tap the Scan button once. Then tap the gateway, and the Invite Devices button on the page that appears.

Tap Network

Tap the gateway

Tap Invite Devices

The red LED of the Launchpad should now stop blinking with its red LED and instead blink its green LED. This indicates that it is working with its secure setup, which may take a minute. When it is ready, it will stop blinking. The Launchpad will then appear in the app.

Tap the Launchpad in the Network view, tap Pin Configuration, and set DIO 23 as the analog input pin. This is the pin that we connected the sensor to. Tap Apply Configuration to instruct the Launchpad to use pin DIO 23 to read data from the sensor.

Tap the Launchpad

Tap Pin Configuration

Select DIO 23 as analog input pin

Now go back to the Launchpad view and you’ll see an Analog Input meter that has appeared. This shows what the sensor measures – that is, the moisture in the flower pot.

Let this run for a few hours and you will have a nice history of the humidity of the soil in the flower pot. Water the flower, and you’ll see it in the graph.

Tap the Analog Input meter

After a while, there’ll be plenty of data

Finally, if you enable the Remote Access button in the app, you’ll be able to see the humidity of your plant, wherever you are.

Conclusion

Congratulations! You’ve built your first prototype. It doesn’t look exactly like those early conceptual ideas, but it is now possible to demonstrate your idea for people to get them excited about your product.

Getting people excited is the first step to get them to become customers – or investors.

Next step is to make the hardware ready for production, to develop your own app with the API, or to connect other sensors to the hardware. We will cover this in upcoming posts – subscribe to our newsletter to hear about when we post them.

The Parts

This is a list of hardware that is needed to build this, with links to Digikey where it can be bought.

Total cost: $86

Optionally, you may want to add two USB power supplies like this or this for some $5 each.


August 25, 2016

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