Hey guys,
So I want to build a robot arm that mimics a controller that uses potentiometers to provide input for the servo position. I would likely be using around 6 medium size 6 volt servos. Since I can't power all of these off the Arduino Uno, can I put 4 D cell batteries in series and connect each servo off this? Will this provide enough current to run say 3 servos simultaneously?
Thanks,
Nick
A lot depends on how long you want the batteries to last. 4 AA NiMh cells may be sufficient. In general, rechargeable batteries can supply higher short-term currents than non-rechargeable types.
...R
Go for high current D-cells then yes. 4Ah or more rechargables for instance. You'll need to
use a quality battery holder which doesn't use unreliable riveted construction for the contacts.
MarkT:
Go for high current D-cells then yes. 4Ah or more rechargables for instance. You'll need to
use a quality battery holder which doesn't use unreliable riveted construction for the contacts.
Could you link me to a specific product that you would recommend?
No, I just have been bitten by poor quality battery holders before.
MarkT:
Go for high current D-cells then yes. 4Ah or more rechargables for instance.
Notice MarkT suggested rechargeable batteries. NiMH cells can generally source more current than alkalines of the same size (I haven't measured this myself but I think it's a safe bet it's true).
If you can get four NiMH D cells or even C (or sub C) then those should work great.
If you can't get ahold of larger NiMH cells, I personally think you'd be better off with five NiMH AA cells than you'd be with four alkaline D cells.
I've done lots of projects with servos. Here's my 22 servo Halloween Hex I show off whenever I think I can get away with it.
Here's my 32-servo demo.
I used LiPo packs and voltage regulators in both of these projects.
I used big 15 Amp switching regulators in my Halloween Hex.
I'm not sure I need both of the regulators but it's very common to hear of regulators going up in smoke as they attempt to power lots of servos in a hexapod. I'd imagine a single regulator would power your three servos without any trouble.
With a switching regulator, I don't need to worry much about the voltage of the battery I'm using. I can use either a 2S LiPo or a 3S LiPo with these regulators.
I'm using something like this battery in my hexapod.
You'd need an appropriate charger if you use a LiPo pack but it's hard to beat LiPo packs for energy density.
While I'm a fan of LiPo batteries, you may be better off with NiMH cells. It's always nice to directly power servos since you can do without the voltage regulator. I'd think five NiMH AA cells should be able to power a single servo just fine. It's very possible five AA NiMH cells could power all three servos.
I used four AA NiMH cells to power this hexapod (the first hexapod I ever made). The servos were much smaller but there were 18 of them. The servos weren't strong enough to carry the batteries but hopefully the video will give a bit of an idea of what sort of power NiMH AA cells can provide.
If you decide to use LiPo batteries and a regulator, let us know and we can offer charger suggestions.
