Gardening - Automatic plant shade

Projects General Guidance
1

Hi, I'm new to the Arduino scene. Hell, I've never even used Linux! I've been putting that in my Maybe Later pile for the last 8-10 years. But I do have C/C++ and MATLAB basic competency - My spring project was a wall-following Mindstorm NXT robot. I want to start a new hobby this summer and don't know what kind of Arduino things to buy.

We have a townhome garden that gets plenty of light in the summer - actually, too much light, and heat. Mostly heat, there is no breeze that runs back there and no good way to install fans to that effect.

What I'd like to consider instead is I can build a simple sun-screen mesh supported by strings and pulleys that can be extended or retracted based on outdoor conditions. It will limit the amount of sun plants get so I don't want it up all the time. Misting plants as some people knew before I did, caused the leaves to boil. Yay.

For this I assume I will need at least access to sensors for light, and heat. I'd also like to incorporate barometric pressure and moisture later, so I can prevent plants from getting watered during inclement rain via weatherscraping or other methods. I would also consider an algorithm that uses a denser mesh that simply mists the plants under heavy shade to prevent the boil effect, then retract after the plants have time to cool (~30 min). I also would need some kind of motor/actuator/server/widget to extend/retract the shade, which I can imagine doing with either a single or pair of motors, either tied to a fixed number of rotations, or to a touch sensor at either end of the line so it knows when to stop?

With that in mind, I don't know which of the many Arduino boards/shields I would need for this project. I don't want to go overkill buying a top of line kit for something that may be incredibly basic, but I also don't want to be so minimalist that if I discover that I need extra ports later that I'm screwed, unless it is as simple as a bigger shield or something.

tl;dr - I would like help with a shopping list for the various boards cords and bits I will need to get a project like this off the ground.

To start:
-Arduino Board, uncertain type
-Shield, if any
-Light sensor
-Thermistor
-Servo(s)/Actuators?
-Touch Sensors?

Also it seems a no brainer to make this concept solar powered, but I am a Mech-E student and my electrical expertise is limited: I wouldn't know what size panel to get or how to supply an Arduino the right current or voltage from one.

Advanced:
-Weatherscraping requirements
-or Barometric Sensor
-Irrigation control expansion

Thank you!

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-Arduino Board, uncertain type

Start with the Uno. It will allow you to read a bunch of sensors and control a bunch of outputs.

-Shield, if any

For what? A motor shield may be useful, if you are using electric motors other than stepper motors or servos. A stepper driver would be needed if you are using a stepper motor (one per motor). None needed for reasonable numbers of servos.

-Light sensor
-Thermistor

These don't need to be all that accurate. Is it light? Is it dark? Is it hot? Is it cold? Those are the questions you'll be asking the sensors, rather than "is it 37.50 degrees plus or minus 0.01."

-Servo(s)/Actuators?

Design the hardware to be driven, first.

-Touch Sensors?

Keep your hands to yourself! Touch sensors? For what? Are the plants supposed to reach out and touch someone? Oh, wait, that's Hallmark's logo.

-Weatherscraping requirements

A soil moisture sensor makes more sense to me. The first requirement is a source of data to be scraped. Then, an Ethernet shield (pretty reliable) or a WiFi shield (about as reliable as Obama).

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Well, temperature doesn't need to be precise to less than a degree F for sure. Even broad readings in C would be fine.

Moisture sensors just seem relatively futile in a garden with dozens of plants. I was considering having the unit track barometric pressure and write the algorithm that would correlate it to inclement weather. But yeah, you can definitely toss in a moisture sensor or two macguyver-style to get some base temp readings.

The reason I was considering touch is because of the mechanical system required. Extending and retracting a shade that is guided along a pulley: it could be easily anywhere between 6-12 feet long, the controller would need some method of determining when to stop the motor, when the shade was fully extended or retracted. A pulley system would operate it in much the same way as a window-blind moving up/down.

Also considering the Arduino Micro, would I run into any limitations with this scale of a project?

4

The reason I was considering touch is because of the mechanical system required.

So, you mean limit switches? Not what I think of as touch sensors. Much easier, in fact.

5

see, I dont even know what a limit switch is, but presumably yes. EDIT: yes thats the proper name. Sorry, the Lego NXT kit called it touch.. we used it for dodging obstacles inside our room :stuck_out_tongue:

Would an Arduino Micro be a problem for this scale of a project? I like the USB nativity, and relative cost

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Would an Arduino Micro be a problem for this scale of a project?

No problem.

7

sweet. Thanks for your help :slight_smile:

8

Automated shade: I have found that even with accurate impulse counting on my steppers, eventually there are small errors that get included and the whole thing goes off to some unintended limits. So, an absolute necessity for a sun shade automation is limit switches. This lets you stop/start on exactly the correct spot every time. I also found that you have to power the up and the down. Do not rely on gravity...too many things get accidentally "snagged", so a deliberate "tug" is needed. I solved this issue with a continuous pulley system and attached my shade (solid panel in my case) firmly to this loop. Thus one motor can power both sides, keeping the shade nice and even in motion, and powered all the way up and all the way down. My axel was simply a 3/4" pvc pipe with proper centered plugs on each end with 1/4" ball bearings. Since speed was not a problem, i used a very high torque, geared magent motor driven by a 298 motor driver chip. Because of the very low gearing, the 12 v DC motor only draws about 200 ma so it is well within the limits of the 298 driver. Although it takes almost a minute to fully raise or lower the shade, it is quick enough for the purpose to protect the plants.

9

Doh - Arnoldo . the thread is 2 years old