Hi,
I was wondering if any one had any experience with these arms. I want to use them for a robust solar cell sun tracker and or automation? The motor is a 36 volt motor ...it also has a reed sensor to count the motor rpm. The specs say it has 48 pulses per inch, kinda figure it may work with 5 volt servo pulses. Does anybody know if there is a relay solution which can reverse polarity on the 36 volt side by inputing on the auduino side?
Easily done with two dpst relays.
Does it have limit switches? That's pretty important in case your relays or controller decides to keep the motor powered.
If you want to know about controlling motors look at:-
http://www.thebox.myzen.co.uk/Workshop/Motors_1.html
Yes it has a mechanical limit switch...I need to only reverse polarity on the 36volt motor and turn it off and on..possible with a relay that switches the polarity and one to turn it on and off;maybe.
Oh yes the satellite has 3 5v leads to the reed sensor and two pwr lines to 36 volt motor.
You seem to be still asking questions that have already been answered. Can you be more specific about what you need to know.
Here's a whole series of solar tracking schematics, etc. http://www.redrok.com/electron.htm
Switching polarity can be done with two DPST relays which take care of polarity reversal and on/off, however; don't activate both at once or you short the battery (same problem can happen with a semiconductor h-bridge) or a single DPDT for polarity reversal and a SPST relay for on/off (which gives you a failsafe after a fashion, both sticking means that you are powering the motor, not shorting the battery, which will burn the motor out unless you have properly working limit switches).
See how much power your actuator puts out at 24V (the solar array voltage never was mentioned), with proper counterweighting it may be sufficient to move the array at a lower voltage than 36V.
Using the Arduino to drive relays is academic, Grumpy Mike's website is a good source for doing this. The one thing you need to do is design in hysterisis so the actuator isn't unnecessarily burning power hunting around a position. The RedRok position sensor uses a Schmitt trigger comparator to do this...
Unless you have a particular need for the satellite actuators, you may want to look at using actuators that have built in internal pots instead of encoders to make the setup simpler. Below are some actuators that are fairly inexpensive and good for projects.
Switching polarity can be done with two DPST relays which take care of polarity reversal and on/off, however; don't activate both at once or you short the battery (same problem can happen with a semiconductor h-bridge)...
Properly wired, I think the shorting should not happen when both DPST relays are actuated at the same time.
Thanks for the links Zoomkat, I've been looking around for linear actuators, they have quite the selection of lengths and force.
I'll have to fiddle with my DPST schematic here and see if I can close both without making smoke... It puts two contacts in the current loop, instead of three which is necessary for the DPDT/SPST combination.
There is a sketch on the below page that shows a two DPST relay setup (note, it is labled SPDT, which is probably incorrect, but it was late when drawn!). Anyhow, when both relays are actuated, both motor leads are connected to the +, so no short should occurr.
Thanks for all the hints people. Just got the audrino board few weeks
ago. Mechanics are my strong suite but I'm learning.