If the 12-5V converter is isolated, you'll also have to connect the EZ-B ground to the sensor's ground.

Would it not already be connected if it's using the same battery? The ground from the battery feeds both the EZ-B and the converter, the converter then feeds the sensor with the same ground... Please correct me if I am wrong on that though.

1) The grounds are shared (Conencted) in TechnoPro's drawing

2) I would recommend using the LM1084 instead of a 7085. The LM1084 has less drop-out voltage, more amperage and therefore generates less heat.

Thanks for the heads up DJ.... I was going to grab a bunch more of the 7805s from eBay... However, I think i will take your advice and get the LM1084s instead....

Cheers
Richard

Am I missing something here.
Why would you not just run the board off of 5-7 volts and then you wouldn't need anything else.
Why do you need 12volts to the board?
Just curious.

Herr Ball, I think that's what the original poster opted to do, no other reason. Some folks are probably making bigger bots (me included) that are just easier to use a 12volt sla type battery. Also maybe the original poster is using wheelchair motors or some other type of device that needs 12vdc.

I'm using 12v 2amp motors. And the ez-b v4 from what I recall can't go under 7volts so a regulator for each assecory or a power supply regulated.

Dimension has some nice inexpensive converters. I've been really pleased with the build quality of their stuff. I guess with the v4 I'll have the same issue since I'm using two 12v sla's and big chair motors. I guess this would be a solution too?


5v switching voltage regulator

Niek brings up a good point. Some switching converters are isolated between the input and output. If you have a converter that is ground isolated, there would be no reference for the signals on the sensor going back to the EZB even though the input to the converter shares the same ground as the battery and EZB. His solution to that situation would be valid. Good thinking @Niek!

@Herrball...Power.... hard to find a battery or power supply to provide a steady 5v to the ezb (to make your sensors happy) and yet will also output some serious amps... Second, most servos need more than 5v to work to their potential.... And even if you use 7.4v lipo, you will now need a way to reduce the voltage from the digital pins that you are running sensors (to 5v)... I like using 12v sla batteries because they are cheap and provide tons of power (amps)...

Sorry guys, I don't mean to be a butt here ... lol ... but that diagram to me, makes no sense at all.
We have to remember that it is talking about a v4.
Why would you want 12volts going into the board?
If you do that then every output pin will be putting out 12 volts.
Way to much for servos and sensors.
Wouldn't it make sense to put the 12volt battery into a high amp adjustable drop down board and then into the v4.
You would then be able to place the input voltage at any thing you want, or needed.

@RichardR I like using the sla batteries too.
You just can't beat then for power and amperage.
I have three of them in my big bot.
Two for the 24volt motors and one to run the mini motherboard and EZB stuff.

Here's something I've found out about feeding between 5vdc and 7vdc into the V4 EZB; If you supply voltage within this range it will shut down the digatal I/O pins and start nagging you in a femail voice that her batteries are low. You can override this in the connections control settings tab of ARC so it will not do this when connected to ARC or after you disconnect. However every time you power up, this irritating event will happen till V4 is able to connect to ARC again. It would be nice to be able to turn this off from it's web server page so the battery tender is disabled from power up. However you can only do it from ARC and the setting must reside in temp memoy till powerdown.

Herr Ball, yes you could do exactly what you said, ie drop down board. There are more than one way to skin this cat. I read somewhere that most sensors are 3.3 volt tolerant which is what is supposed to come out the analog in ports (I believe). You are correct that 12 volts is too much for most servos. I think the steady supply voltage to the ezb board is what some are shooting for here. As I now see Dave has posted above this and his post seems to follow this theory

thank you for bringing that up that point Herr! I just realized that I forgot about the servos! ok so I think ill use my setup with a 5amp regulator set to 7volts and then put lm1084s in the sensor lines to regulate lower. Thanks everyone!

Does anyone know a 5amp 7v regulator? I've been looking and cant find one. I want it to be under $10 if possible.

I would guess you'll need an adjustable regulator to output 7v. And requiring 5A may be an issue.

That said, are you sure 5A will be enough? How many servos etc. will run from it? It only took 2 TowerPro MG995s to brownout my V3.

Maybe out of you budget, but the guy has 100% positive feedback and free shipping...
Adjustable regulator

I don't mind this DC Converter....

http://www.eachbuyer.com/5-30v-to-0-8-28v-dc-boost-buck-converter-5a-constant-current-volt-regulator-p238353.html?currency=USD&utm_source=google&utm_medium=CSE&utm_content=[Consumer+Electronics]&utm_campaign=[PLA]America%28EN%29&gclid=CKbd-fXKu74CFVQFMgodQggAYw

It's a cheap one and I believe it only truly has buck capability (no boost). It's small and gets the job done. It may take a little tinkering to get the trimpots adjusted correctly since there's no instructions. One trimpot sets the voltage and the other sets the current limit, from what I can tell. I got a couple of these and they seem to work fine.

Here is one I saw on eBay that says it can handle up to 12A.
{Disclaimer: I never used this seller or this product.}

DC-DC Adjustable Voltage CC CV Buck Converter 7-32V to 0.8-28V 12A 300W

Here is one I'm looking into for higher voltage servos.

(DC 12V/24V to 7.5V) (20A 150W) (STEP DOWN) DC/DC Power Converter Regulator