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Author:hectorhhgI am an engineer and lover of innovations!
Intro: Stepper Motor + Arduino + Solar Tracker (EV)This instructable is the translation of another that was originally written in Spanish, so I beg your pardon if I have many grammatical errors, if so off I'd love to suggest meto edit it. I just do it because I like to share my projects.
It is a solar tracker, but not before mentioning my inspiration were devices by geo bruce and aplavins, except in my case use stepper motors, which can reduce the priceof motors and increase capacity for freight or moving ;).
We all know that the trackers have the advantage of increasing the efficiency of capturing solar energy, as the Earth continues its noble movement, the project reflectsthe importance of this phenomenon and try to design a simple tracking system that can facilitate the installation. I hope I can be as explicit as possible and try to eliminateall doubts.
Arduino UNO R3wirewoodpaintTruack safe w / outer 5/8 "
Step 2: Structure designThe proposed design consists of a system with biaxial rotation with a cylindrical base, which allows to track the sun in an efficient, in addition to being compact aspossible to avoid a large space area.
In principle, I will simulate the prototype, it is a way that I have taken to prevent the fewest errors (although often it slip :)), try to use other materials if they deem fit,provided that enable run movements chords.
Step 3: Solar PanelTo fasten the solar panel will be used a base formed by L profiles, better known in the market as angle, which rest the photovoltaic module. This base will be supportedby a pair of square bars to the ends of this, so that the weight can be balanced throughout the system and in turn this will be subject to an axis to perform the azimuthalmovement. It is important to note again that the entire assembly described will be very light to avoid the use of motors with large dimensions, since it would increase thecost and complexity of the system.
The pair of bearings facilitate it operation, which it will support on top of the cylinder. For this a couple of bearings that will remain fixed to the base is employed. Using thebearings can lay the ball bearings and the shaft to rotate and rest at a time.
Step 4: Azimuthal movementTo seat the bearings, a few pieces of stainless steel having the same outer diameter having the cylindrical base, in this way are used, the bearings can rest on smallsurfaces, it is important to note the cuts made in the base, some will allow crossing the axis, while others are only to reduce the weight of the device (also I did it foraesthetic ;)).
With these elements we can achieve the azimuthal rotation, just need to have a circular transmission mechanism, either through a system of gears or pulleys with belt.For simplicity and softness, it is necessary to use the second system, ie, we can hold the shaft holding the base of the solar panel in the middle, by a driving pulley. Toprevent slippage cause a toothed belt pulley and a belt with the same feature is used.
Step 5: Zenithal movementThe next step is to run the other movement (zenith), this in turn shows no big deal and can be performed with different mechanical elements. It was decided to use atransmission mechanism circulated through a system of worm-gear at the bottom of the structure. This set is used when you want to transmit large efforts and increasetransmission power. Usually works in intersecting axes to 90?.
There are many difficulties when a gear system is used, but the most common problem is when you work with variation between their centers of operation, so it must beassembled precisely to ensure a smooth operation.
The system worm pinion allow rotating the device, thanks to the mount to polymer disk, ie, the axis of the crown is coupled as male, whereas polymer disk fit as female(hopefully to appraise in :( images) Since the diameter of the disc is similar to the inner diameter of the cylinder and this is very large, the polymer disc should be reducedso that it can seat a bearing with a smaller diameter.
Actually the UCF oarlock subject the disk by a set screw, while the cylinder is held by the latter by set screws. Basically, using these two systems we can provide therequired movements in the project.
Step 6: PrototypeFinally one can notice the device assembly, in the first figure I put a transparent material so that they can be seen the assembly of the mechanical components, as for thesecond figure, is a prototype simulation.
So they can appreciate views of the prototype, I leave the video below:
Step 7: OperationLDRs help to determine where there are more light during the day, these were placed in the corners of the panel, grouped in such a way that can be seen in the previousfigure, that is, a pair at the top and a pair at the bottom. For greater accuracy as to the brightness measuring, photoresists should be cover to avoid picking around thediffuse solar radiation, in other words, the propagation of light (electromagnetic waves) that are scattered and reflected in the atmosphere.
Grouping the sensors allow to determine and execute both movements, for example, groups of LDR called left and right, are compared and if a higher or lower rangedetermined to sensitivity difference then be executed a corresponding movement, of equally to the groups of top and bottom sensors, only these will determine themovement of the other axis.
I also determined the average radiation between the four sensors, for what ?, so the idea is that at the end of the day, when solar projection is zero, the panel base rotatein the opposite direction, in dawn, hoping the next day, the sun comes out again.
OPTIONAL
I also make use of a photodiode, it is the BPW34, also deals in control, if you wish, you can skip this sensor, since the main application which I used it was for to measurethe solar spectrum and record amounts of radiation solar which was subjected to the photovoltaic module. Remember to modify the code if you do not use it.
Step 8: Electronic designIn this step I show the circuits that were used to develop the prototype, don't forget to check the datasheets of drivers, that to determine whether they are able to movethe engines that will occupy.
dit = (ltsensor + rtsensor)/2; //Average sensors up
did = (ldsensor + rdsensor)/2; //Average sensors down
diff =(dit - did); //Difference between the level of radiation
delay (50);
if ((pyr==0)&(pup==HIGH)&(prom<=8)|| (pyr==0)&(pdown==HIGH)&(prom<=8)) //If the value of pyr is zero and the average of the sensors is equal or less than 8 and theswitches have the range
mov(); //mov function
}
while ( (pyr==0)&(pup==HIGH)&(prom<=8)|| (pyr==0)&(pdown==HIGH)&(prom<=8));
if (-1*sen > diff || diff > sen) //If the measured difference between the set of sensors is greater or less than the sensitivity value
{
if(dit < did) //If the mean value of the above sensors is smaller than the bottom sensors
{
if (pdown==HIGH)
{
verStep.step (0); //Stop vertical motor
delay (10);
}
else
if (pdown==LOW)
{
verStep.step (v); //Turn motor up
delay (50);
}
}
else if(dit > did) //If the average value of bottom sensors is smaller than the above sensors
Step 10: Process and assembly of mechanical partsWell, it was time to pass the ideas to reality;). Needless to emphasize the coupling of the mechanical elements (I hope you have understood in the simulation), just showthem some of the machining processes you use to create the pieces. And I can assure you that working with stainless steel is hard :(, but the finish is great, besidesbeing a material that supports the extreme weather.
I share you the design files that I used for the prototype, these are in Spanish but you will have no problem interpreting, all dimensions are in milimeters..
solar tracker.pdf (1 MB)[NOTE: When saving, if you see .tmp as the file ext, rename it to 'solar tracker.pdf']
Step 11: Final tests!Finally, when the mechanical part is finished, it is time to place each of the sensors and electronics. At the moment I do not have a solar panel :(, but I used a foam plate:) finally paint, looks great, What do you think? XD. I suggest that the resistors having the configuration of pull ups for LDR and switches, place them as close to these, Irealized that it generated erroneous data when put to a longer distance.
What is the function of limit switches?, prevent the panel moves down and can collide with the base of the prototype, is why a piece of washer was placed concentric tothe axis and while it rotates, reaches the point where pressing switches are subject to the bearing, so that is the displacement limit of the solar panel.
Keep all electronic components in a case, keep doing magic those with 3D printers or laser cutters and avoid using a box of chocolate like me :( haha.
To close with a flourish, I leave a video where he did some tests follower :). See you soon!