Project to be edited... first test image

[Externet]

Project tracker text incomplete, edit ---> add here.

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[YT2095]

a Solar powered stepper motor driver.

what`s it for?

[Externet]

Fully self contained unnatended heliostat. Need to add/post other modules later.

Miguel

[Rocket Man]

i'd have used the solar panels to run four light dependant resistors, a small binary amp and two dc motors running wormdrives. you could get far more reliable movement out of a set like that and it'd be more efficient that way.

rather than having to run a stepper and controler the whole time, you'd be running a smaller dc intermittently.

[Externet]

Disagree.

Light dependent resistors won't work when cloudy even with lenses, losing tracking. If gets cloudy by 3pm, photocells would not see the next sun at dawn to re-aim.

A DC motor will not provide a defined exact angle of advance by its wear, thermal and frictional variations.

Yes, stepping has its hurdles too. The one I have to solve is to shut it off between steps while remembering which windings to be energized on the next step.

Have it running for 48 hours now, pictures to come soon.

Miguel

[Rocket Man]

well done at getting it running.

 

a screw drive on two axes locks the angle between adjustments. a light dependent resistor can be used to shift the angle only when it needs to and only by as much as it needs to. it doesn't depend on the angle in the motor, rather it self corrects when the error gets high enough. four LDRs stuck in a semi transparent sphere with a baffle in the middle makes most of the motor control mechanical and optical.

 

i don't see how cloudy conditions need to be accounted for, why track the sun when it can't be seen?

with a spherical detector, it'll see dawn sun and track accordingly no matter which way it faces initially.

[YT2095]

with a single stepper I gather you`re not doing the full pan/tilt, and just sticking to pan?

[Externet]

Just panning... for now.

Would love to implement a pure mechanical ratcheting for tilt, but suspect it will end with another stepper moving a cam once a month for that.

Miguel

[Externet]

It works !

 

Solar cells and Li-ion battery; precise timing source, dividing/counting logic board, stepper driver board and the mechanism.

 

The black aluminium massive base on the mechanism provides a solid, ball bearing mount for the vertical shaft. The worm screw on the motor shaft steps once every minute, changes direction at 06:00 am and at at 06:000pm. The rotating table support for the mirror (shows a tiny mirror on the picture)

 

Needs cosmetics and arranging all the electronics, inside the black base there is room for them.

 

 

Miguel