I was wondering what your thoughts are about using the power off the solar panel to turn the motor one way (when sun is present), with a limit switch once the motor reaches its destination. Then using the battery power to push the motor the other way when there is no light, also with a limit switch to prevent the batteries from draining, maybe adding a photoresistor like solar lights have to prevent the motor from wanting to run in the other direction as well. Somehow still allowing the batteries to charge during the day... I just found http://www.evilmadscientist.com/article.php/solar , which is the perfect size solar panel, and is apparently supplying 4.5v at 90ma. Would something like this work?

 

If the CMOS version 7555 is available for you, then you could try that.. It works from 1.5volts.. when you use it on 3V, add a 1N4001 diode in series with the 3.6v battery to drop the voltage to about 3v.. Then you can use two 3v relays.. Are 3v relays and 7555 available for you??

The 555 section can also be replaced by a transistor pair eliminating the need for a 6v..

Can try solar bot type circuits too.. They have photo detectors for direction tracking and a motor for drive control.. minor modification might do...

Or you can go op-amps with H bridge or PWM.. H bridges require 2-3 volts higher than your motor voltage. which gives 3.2-4.2v... Hmm... give it a try..

My final idea... I cannot gaurantee its working.. but should work.. runs at 3.6v, provided u use one 3v relay..

 

Actually I don't have anything to start. It's just something I'm trying as a learning experiment so I'll have to order parts. And trying to keep it cheap.

 

Hmm.. according to Indian currency, 2 relays and a 555 will cost less than a dollar only..

 

Or when some companies have minimum order numbers, then jack up the shipping and handling. Luckly I work for a cable manufacturing company and our vendors are always willing to give us samples... It may take a bit to get everything together, but it may cost me $0.00, no matter what currency.... That's cheap!!! =D

 

You are lucky for that !! Here we dont order parts... Get them directly from retail dealers at cheap rates. Wholesale makes it even cheaper. So you decided your circuit??

 

I like the second one you did. Now I just need to get a parts list together. Thanks for the help!

 

I think it needs a few resistor adjustments. Ill write in as soon as I figure them out.

 

I reanlaysed it. It works to serve your need but has a serious problem according to your requirement. The relay will run during one part of the cycle continuosely, which draws a lot of current, say 20-50mA which is not good. It is simple and great but not for your application. You can use the first circuit with a current draw of 5uA only if you use a 7555 CMOS IC... That is the best option for you.

 

Lots of progress while I was away, so I'll just throw this in for good measure.Q1 & Q2 shown as open collector, non OC would be bettrr & would eleminate R2 & R3.When sun shines D1 is conducting causing comparaton Q1 output to go Hi. R1 & C1 form a time delay to prevent spurious activations [1MΩ & 100μF guestimate ]. R3 & R4 same high value[56k to 100k ], R2, R3 & R5= 100k if used. Q3 not needed if Q2 can drive H bridge.Open circuit V of solar panel should be about 1.4 X battery V + D1 drop. Saw an add in All Electronics # SPL-05, guts of solar light, 2 batteries panel 3.78 X 1.98 in., 2.6V @ 25mA. Two would give panel about 4 X 4 in.& 4.8V battery. $3.00 ea.

 

Might check thread by jayci , similar project using H-bridge SN54410.

 

Sorry, almost forgot second page containing limit switches which are normally closed and should stay open untill motor stops , when activated. The gate inputs from the limit switches are normally tied Hi. When top gate in is Hi [sun up ], out is Lo, lower gate in, after inversion, out Hi , giving H-br, a Hi & Lo rotating motor CCW or West. When W limit SW opens , H-br has H-H stopping motor. When in. is Lo H-br is reversed untill limit SW-E is opened, again H-br has Hi-Hi stopping motor untill sun comes up again.

 

Wow this seems above my head. I was also wondering if someone could recommend a free circuit simulator, something that has an easy drag and drop function.

 

With only two IC's & some resistors it would be reasonably easy to assemble the circuit on a socket strip & some 24 ga[ telephone wire ]. If you decide to try, we'll supply pin numbers & step by step if necessary.

 

Here is the H-Bridge I made.

When I reverse the polaritys at point A & B the motor works as it should. My question is now, What ICs or other parts do I need to order to build the circuit you suggested. The panel I would like to use is listed at http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=12269. 4.5v at 90ma. Will this work for what I'm trying to do?

 

I suspect V given is open circuit, will drop to about 3.15 under load, subtract .7 for blocking diode & it will bairly hold 2 charged NiCd's . Two panels would be great. Congratulations on H-bridge. So you are go to build,'will look over drawings and come up with parts list. Do not know your set up , so not sure of type of limit switches to recomend.'should add at least a .1μF cap across motor terminals.

 

Will that panel be insuffecent for charging the batteries during the day? I was just trying to keep it as small as possible. Did I not need the H-bridge? I just thought it was needed to connect to the first scanned schematic. I'm trying to get a motor that will turn a set of gears which in turn will move about 1-2 lbs of weight to the left, then to the right. Sorry I just don't know much about circuits so I have no idea of the load or what is needed. Thanks for everyone's help!!

 

Does the load run on wheels on a track ? Can you make a simple drawing of operation? On a smooth surface or track not much power is required if there's no hurry. What motor did you use for H-br. test? Do you have a multi-meter? All 3 pieces are used, light detection, direction control,& H-br. for motor drive. Would be nice to know motor current. Are you going to use a socket strip or individual sockets. The comparator is LM339, 4in one IC. With low impedence of H -br, will parallel another 74HC00 with existing. More later, I'just rambling now.

 

Bear in mind that you can easily "smoke" this H-bridge by supplying Vcc with the control inputs floating. Avoid that flaw in your design early itself. Also add an inverter or buffer chip to the H-bridge inputs like a 43HC14 to avoid troubles. Is that 2N4403 available to you? You could replace Q2,Q4 with BC327-25 or 2N2905A and Q1,Q3 with BC337-25 or2N2219A to easily run a 360mA motor. Also change those 2.2k to 1k's. I guess your motor current is near 120-150mA. If your current motor is geared, it will run that load.

 

I picked up a multipack of PNP transistors from radio shack, so I just used the to toy with. I'll look and see what else I have, but my current supply is limited at the moment. The load isn't on a track, just a plastic guide. I'll see if I can sketch something up. The motor I used was http://www.radioshack.com/product/index.jsp?productId=2102828&y=10&x=8&retainProdsInSession=1 . But this won't be the motor that I'll end up with. Instead I have this cordless screwdriver (http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=91332) That I'll eventually take apart and would like to use. I do have a multi-meter. Currently I'm just using a bread board to play with.