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Solar Tracker Using 555 timer

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you can share any problems here, i just want to say though that i think that everyone in this thread is being a little redundant. you don't need to use stepper motors, in fact if 3v0 was here he would beat you all senseless with your own ideas. you can get the same results using this circuit. if you have any problems with the circuit, then let me know and i will fix them, i think that i made a minor mistake on the two inputs on both op-amps. if you have a problem then switch the inputs on pin 2 and pin 3 on both op-amps before you come to me please.
 

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if you want to know how an op-amp works in detail, then read this: READ!!!. if you want a long story short; most op-amps can handle a dual rail power supply. when the non-inverting (+) input is higher than the inverting (-) input then the output is high. depending on weather the op-amp is on a dual rail power supply or not, 2 different things may happen;

1.) Dual Rail: if the op-amp is on a dual rail power supply, then when the inverting input is higher than the non-inverting input then the output will read a - voltage in respect to ground (the op-amp is trying to allow current to flow from ground to the - voltage source.

2.) Single Rail: if the op-amp is on a single rail power supply, then when the inverting input is higher than the non-inverting input, the output will be 0V.

196-770px-741_transistor_level.svg.png


see that 30pF capacitor? that capacitor is in most op-amps, but it's value may vary depending on the op-amp. this capacitor causes what's called a slew rate in the op-amp. the slew rate is simply referring to the frequency response of the op-amp. as a rule of thumb as the frequency increases, the response of the op-amp decreases. once you pass a certain point then the op-amp stops responding all together. for the 741 operational amplifier, which is the one in both of my images, the drop out frequency is about 1MHz. if you have an op-amp and you want to know what the characteristics of it are; you can look it up on this site: LOOK IT UP!!!
 
Perhaps the most logical and easily built sun tracker I have seen is Super Simple Sun Tracker. - Jose Pino's Projects and Tidbits. . Of course you would not want to copy it as your own, but by studying his example you will see what is neseccary to make an object follow the sun all day, then reset itself for the next moring.

Take a look.


Edit: it becomes necessary to correct the spelling of neseccary.
 
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There's nothing wrong with the idea of using steppers for this application, and it's actually a cleaver idea. But the system needs to be better specified. Properly done, the stepper system can provide a certain amount of damping, and thus better control, something the bang-bang opamp circuit doesn't have.
 
Thanks Dragon....

I've simulate your circuit....is it should look like this???

Correct me if I'm wrong because I've run the simulation and nothing happened...huhu
 

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you are really close in your design, the only mistake you made is the limit switches, change them to PBNC and it should work fine.
 
There's nothing wrong with the idea of using steppers for this application, and it's actually a cleaver idea. But the system needs to be better specified. Properly done, the stepper system can provide a certain amount of damping, and thus better control, something the bang-bang opamp circuit doesn't have.

true there is nothing wrong with using a stepper motor, but for something this simple then you don't necessarily need to use the stepper, you can get away with using a regular motor and op-amp. as long as you use a gear ratio to slow the motors speed, normally the sun does not move fast enough for either a 741 or a CdS to respond to it appropriately. hence the gear ratio to slow the speed so that when the motor is activated then the circuit has time to respond to the change in light. you could also use a circuit like this:
 

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The stepper is simple. Who says you need comparators and relays? The stepper is inexpensive, requries no gearing, has pleanty of torque and can position the apparatus very accurately, is simple, and as I've pointed out, can provide a certain amount of damping if done properly. Overall, the stepper solution turns out to be as simple and more accurate, considering the total system. Further, it would be easier to stabilize the system if using the stepper. It's a very cleaver design, once you grasp the details.
 
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ermm...about my project, if I'm gonna use op-amp, I must change my title because my idea is to use 555 timer...is it difficult to use the timer???
 
Timers are simple, but if you're using the opamp solution, a timer is not required.
 
**broken link removed**

This project has a number of mistakes in the circuit. Each output of the 4017 is driving 3 other LOW outputs and this will put an enormous strain on the chip. A 4017 will deliver up to 100mA on short-circuit at 12v and the chip will get very hot.
In addition, the designed thought that by resetting the 555, the 4017 would also be reset (he did not use the first output). But this is jot so and the stepper motor will be powered ALL THE TIME.
Rather than his suggested 25 microamp consumption, the circuit will be taking 100mA plus the stalled current for the stepper motor.
On top of this, all the outputs are connected together and the buffer transistors will ALL be active at the SAME TIME!
A very bad design mistake.
I have contacted the designer and he is unaware of these design mistakes.

He has just replied to say he has never tried the circuit !!!!
Why put a circuit on the web that has not been tried? He gives the impression in the article that the circuit works perfectly with comments like this:
no FALSE TRIGGERING, a Very ACCURATE System.
The circuit has been well thought about long before posting it on the web.
The whole System draws only 25 MicroAmperes of Current when the Motors are
not rotating.

Nothing is true.
 
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colon55; very good observations. I don't think the 4017 should be reset at all, rather the stepper drivers should be turned off during the reset time. The 4017 should take up where it left off at the end of each movement. But I'm not even sure that chip is the best to use for driving the steppers. I'm sure there are better choices, though I'm too lazy to research this.
 
Here is the reply from shoumik banerjee <schawn143@yahoo.com>

Your logic is the worst logic i have come across in quite some time dude.....All this has already been explained by me.Do you want me to run an infinite loop for you? CD 4017 will not be off, it will just start producing output from pin 3 onwards once it is triggered at its 5th output. So no combination is a problem. The only problem is with your suggestions. Well, I DONT NEED THEM.Read my article properly first and then comment.Read my article properly if you want to, otherwise keep calling it illogical, it DOSENT MATTER to me.GOODBYE.


Can someone tell me what he is talking about?

When all the outputs are connected together and one output is fighting all the others, how can you expect the circuit to work?????

He obviously doesn't want to listen and learn and that's what makes his project so dangerous. Not only does it not work, but it will most likely overheat the 4017. And he is obviously not going to test the circuit. Only a fool puts a circuit on the web without testing it. And arguing, after being told it does not work.

I find it particularly annoying to find projects on the web that have not been tried, but purport to work perfectly and draw-in the unsuspecting hobbyist.
As you can see from the original posting, the reader had no idea the circuit was a FRAUD.
 
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if you try to run a stepper motor with a 4017 then you have a problem. the problem is that you need to have transistors connected together to run the stepper. even then you still have some problems. you would need to use a stepper with only 2 control leads other wise you have the motor "stutter" at the end of the 4017's cycle. if you use a stepper with only 2 control leads, then you have the problem of lost accuracy. BrownOut, i'm surprised that you don't remember this from my "Printer to CNC" thread.

if you can't remember, here's a link:
LINK!!!

if i remember correctly then you criticized me for doing the same thing.

i don't know why your against using an op-amp. even a 741, i always use a 741 in my circuits before i try a different op-amp, unless a different op-amp is immediately required. if you use an op-amp then you can replace the 741 with a quad op-amp and he can make a north south function as well, if he doesn't want to use the relays, then he can use transistors and make the circuit more sensitive to the light.
Circuit

Resistors R7 and R5 should be as close to the CdS' standard resistance value (what it was advertised as) as possible.
 
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First of all, I have no idea what you're talking about either when you talk about connecting the transistors together, or when you talk about the stepper stuttering. Neither of those statements make any sense to me. I skimmed over the thread you linked, but don't know why it's supposed to be relevant. Also, when did I say I was against using op-amps? I never said anything like that. I only said the stepper idea is a good one, is simple to implement and offers some advantages over the primative op-amp solution. I disparage no op-amps.
 
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Thanks all for your reply....thanks for your help...later I if got any problems then I'll share it here...this forum really help me much...^^
 
Thanks dragon...I've simulate your circuit and it work...but, I still don't get the exact switch you mention before..the motor run but never stops...what kind of switch is it???

Also I want to ask about the motor, which one is better to us in this application???servo or dc motor???
 
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