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Asked — Edited

Saber Tooth Connection Question

I have already asked and got an answer for this but just noticed that the saber tooth help page says something different.
Quote:
The EZ-B connects to the GND, +5 and Signal to the Sabertooth. The Signal from the EZ-B connects to S1 on the Sabertooth.

Got that the signal goes to s1 but then there r the other 2 that are different.


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#2  
Yes, connect Ground & +5V from the EZ-B to the 5V and 0V to the right of S1
#3  
If you use the 5V and GND on the Sabertooth then this is how you hook it up....


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United Kingdom
#4  
That's good to know if it is as your image, I certainly wouldn't have thought that until you posted it. The tutorial page I read as saying to use the +5, Gnd & Signal from a Digital port to +5V, Gnd and S1... I guess I interpreted it wrongly?

But, wouldn't that only feed the EZ-B +5V, which may be within it's limits but only barely...
#5  
I hooked up a different motor cotroller that way, and then I noticed that when I unplugged the EZ-B it was still on. The 12V feeding the controller was outputting 5V from the controller to the EZ-B. After that I just connected the common ground and that was it.
#6  
Yeah, the Sabertooth has 5V BEC output specifically so that it can power micro-controllers.

As far as 5V being within the EZ-B limits, I would think as long as it provides a constant 5V it should be fine, since the power input voltage regulators on the EZ-B drop whatever you are feeding it to 5V anyway, and throw the rest away as waste heat.

I am planning on feeding 24V into my Sabertooth (driving 24V wheelchair motors) and then use the 5V Bec to power the EZ-B. The Sabertooth has a bigger heat synch, so I will let it handle dropping the voltage for the EZ-B.

Alan
#7  
I don't know too much about this, and this may be a dumb comment, but if the 5V output from Sabertooth is connected to the 5V output on the EZ-B, is it even going though the regulator on the EZ-B? I would think that the regulator would be between the barrell jack an the 5V circuit. That is why I disconnected mine. I was afraid of damaging something.
#8  
Of course that's not to say that you couldn't power EZ-B off of it. I would think that you would need to disconnect the EZ-B power source.
#9  
Here is the page from the Sabertooth manual for my 2x12.
The 5v output from the Sabertooth can only power small loads up to 1 amp.

I personally don't use the 0 and 5v on mine. I always power my electronics separately from my motor control circuits to help eliminate any potential electrical noise problems. When you use a separate battery for the EZ-B is when you need to make sure you connect the commons together as shown in Technopro's first drawing.

Also if you think about it, basically you would be hooking 5v to the 5v regulator input on the EZ-B. I have never tried using a regulator with an input voltage that is the same as the output voltage.


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United Kingdom
#10  
I still learn new things daily, which is great:) This kind of thing is where I'm still rusty so it's great to see all the info and comments.

From the looks of it the 5V on the Sabertooth is only 1A though, which may cause problems if running high power servos like the Tower Pro MG995s (which I have just had to supply externally from the EZ-B due to browning out the LCD and possibly being the cause of disconnections).
#11  
@Danger!, you are correct. If powering the EZ-B from the Sabertooth, you would connect the +5 and Ground to the Barrel jack instead of the existing power, but @Rich has a good point about the limit being 1 amp. That may not be enough to power all of the servos and other devices connected to the EZ-B (and now I need to re-think my plan).

Alan
United Kingdom
#12  
5a 6v regulated supply from the battery to supply the servos would get around the 1a limit. Simple with a basic regulator like the one I have in Melvin. Or multiple regulators if you have a lot of servos.
Sensors etc. Should be fine for the 1a of the sabertooth... maybe.

Food for thought:)
#13  
ok. thanks for all the comments.

so my drawing is correct for powering the ez-b with a separate battery.

I will only be using it for one micro servo at first and then 2 more normal servos later for a camera movement.
and quite possibly a distance sensor.

to power all that I would want the ez-b separate from the sabertooth power, right? like in my first drawing?
#14  
That seems to be the consensus, Technopro.
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