I installed it yesterday, and it over watered the first day. I made some adjustments to the thresholds and we'll see how that pans out. Figure 2 shows my overwatered plant.

Figure 2: Overwatered plant.

Air Conditioning Update

I've set to work on the Air Conditioning Switch. Figure 3 shows a collage of items showing some details from the air conditioning switch design. In the upper left a diagram is shown that details the measurements and physical layout of the air conditioning unit switch mechanism. Note, I live in an apartment, and therefore cannot alter the unit itself. It would be easiest to use an electrical signal to turn on and off the AC, but, it is what it is. The requirement was to turn the AC on and off remotely. Below on the left is my two solenoid arrangement that has a travel of 5 mm, Driving the left solenoid pulls the two plungers to the left and driving the right solenoid pulls the two plungers to the right. The plungers are coupled together, ideally by a bracket, but currently by a dab of super glue. The picture on the right shows the AC interface. You can see the switch in the lower right of the picture.

Figure 3: Air Conditioning Switching

Figure 4 shows my design for the solenoid driver circuits. On the left is the header for the Raspberry Pi B+ and on the right are the two solenoid driver circuits. R1 and R2 are pull down resistors that ensure the solenoids are not energized while the Pi is booting. Setting GPIO17 high turns on transistor T1 and energizes SOILENOID1. D1 provides a path for current when the solenoid is de-energized, and is appropriately called a free-wheeling diode (also known by snubber, clamp, and flyback diode). The circuit for SOLENOID2 is the same as the circuit for SOLENOID1.

Figure 4: Solenoid Driver Circuits.

I do not have the components yet to build this circuit, but I've tested my solenoids with a 5V power supply. Only one solenoid is driven at-a-time.

My intention at the beginning of this challenge was to learn because it would stretch my skill set. I've definitely been stretched, not only as an engineer, but also as a procurement agent and project planner. So, thank you to Element14 and Newark for giving me the opportunity to compete.

Top Comments

michaelwylie over 11 years ago in reply to DAB

That's a neat idea! So, just once a week?
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DAB over 11 years ago

Reminds me of my first automated furnace control.
A DC motor would move the temperature switch manually at set times in the day.
You could hear the click followed by the whirr of the motor to move the temperature selector.

My wife has gone to an ice cube watering system. A group identified how many ice cubes each type of plant needed each week so she loads up the ice bucket and goes around the house putting ice cubes into the pots. Seems to work, less brown plants abound the house.

DAB
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fvan over 11 years ago

It's really a pity your parts didn't arrive in time

But still great work done on the water system and explaining what you are planning to do, should you have the parts.
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mcb1 over 11 years ago

At least you didn't flood the house, just some plants got wet....

Pity you didn't have a 3D printer, otherwise you knock up a cam arrangement, and drive a stepper.

I see that there are Airconditioning controls within openHAB and I'll bet none of them suit yours.

The end is definitely close, and its been a great learning opportunity.
Mark
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Forget Me Not: Episode 14 - Nearing the End

Previous Posts:

Update

Plant Watering Update

Air Conditioning Update

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