Have you ever used these servos https://www.amazon.es/gp/product/B071GNNTFG/ref=ox_sc

abenn

Senior Member
Adequate for what? What is your application?

They can be controlled by the 28X2 using the servo commands, but you won't get the quoted 20Kg.cm torque when using the standard 5v supply.
 

Danielpbt

New Member
Thanks for your answer. My intention is to use it in a small humanoid of about 4 kg of weight. My question was in relation to whether the processor could handle digital servos. So far I have only used analog ones.
I would like to know if it is possible to modify the standard supply from 5v to 6.6V, without damaging the board. I know there are voltage stabilizers, but I do not know if it's possible to use them here.
Thanks
 

abenn

Senior Member
The servo will work fine on 5v, but it just won't give you the full advertised torque. If torque is important it's quite easy to devise a circuit that runs off 7.4v (the servo's rated maximum) and incorporates a regulator to ensure the PICAXE itself doesn't get more than 5v.
 

Danielpbt

New Member
You would give me an example, I am somewhat lacking in form and I am capable of complicating myself. My sources are 6V, I guess that limits us a lot, right?
 

rq3

Senior Member
You would give me an example, I am somewhat lacking in form and I am capable of complicating myself. My sources are 6V, I guess that limits us a lot, right?
Your servos are specified to have a torque of 20 kilogram-centimeters, which is HUGE!. If you put a 2 cm. diameter pulley on the servo and wrap a string around it, the servo could lift 20 kilos with that string when running on 6.6 volts! At least that's what they claim, but I don't know how long the servo gears would last! Even running at 5 volts, I would estimate the torque would only drop to about 12 kg-cm, which is still HUGE!

In either case, your 4 kg humanoid could easily throw itself across the room.
 

rq3

Senior Member
I'm looking forward to seeing them work. By the way, it is possible to graduate your speed in some way?
The speed of the servo will depend on how far you tell it to move, and how often you tell it to move. The servo itself will always move as fast as it can between positions, but if the position steps are very small and have a time delay between them, it will appear to move very slowly.
 
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