Solar Tracker Update

1 Axis System

1 Axis System

This blog is a follow up from the previous Solar Tracker Article I posted up. There have been changes as I have progressed so please have a look at this Post for updated information.

In preparation to building the solar tracker I had to test out various parts and run some programs that ensured everything was working fine.

I initially did a servo sweep which is built in on the Arduino software to ensure both servos were working without any problems and checked if my connections were all the right way round.

After this I tested out various resistances that were needed for the LDRs.  I used 1K, 10K and 330 Ohm resistances but noticed the best response when the LDRs were connected to the 330 Ohm resistor. The circuit was basically a voltage divider (a circuit that produces an output voltage that is a fraction of its input voltage).

Ohms Law gives  equation that relates the voltage to the resistance.

 

OHM
I am not going to go into too much detail with experimental testing procedures but the link below is useful if you need to calculate values for fixed resistances that would be requiredfor your voltage divider circuit.

http://www.doctronics.co.uk/ldr_sensors.htm

I then tested out the different fluctuations in the values on the serial monitor by just covering the LDRs, it gave me responses to its light intensity when I covered it or exposed it to light as shown in the video.

Moving on, I initially was meant to use 5 LDRs but have now stuck with 4.

 Breadboard

The picture above shows the breadboard of the one axis system that was completed. I have attached all four LDRs (tracking light from the left, right, top and bottom). All wires needed to be connected the right way around to the 5V and Ground pins on the Arduino and breadboard, especially the wires that connect the servo as this could lead to the servo being fried!!

One complication I came across was that one motor  did actually get burnt out and had problems with rotation as it kept swiveling back and forth without going into position smoothly. Hence me not being able to complete the second axis in time for this blog as I am still waiting for the motor to arrive.

You can see that there wasn’t too much space on the breadboard so had to make do with the confined spacing. I will probably move the LDRs so different positions once mounted on the structure. I have compiled a fritzing drawing of the breadboard and schematic view of the setup which gives you a more clear representation.

Solar Tracker sketch

Fritzing sketch

Fritzing Schemetic sketch

Fritzing Schemetic sketch

The above diagrams gives you the basis of the connections made for the two servos.

The video I have uploaded shows the motion around 1 axis . I hope to mount the sensors along with the breadboard and arduino on top of the two motors which can be embedded into a miniature leaf once complete to display the effects of Photo-tropism as a separate piece from RoboPlant.

Thanks for taking your time to read this blog, I will post another article once I have completed the solar tracker with both axis’s working and have a mount sorted out for the solar tracker.

Murtaza Lukmanjee

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