Asked — Edited

What Ac/ Dc Adapter Should I Use

I just have a quick question. What kind of AC/DC adapter should I use? I just want to be sure not to break anything. Right now I am just working off of battery which dies off quickly some times. Thanks!


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Depends what robot your ezb4 is in.... If you are powering many servos you will need at least a 6V or 7.4V 20 amp power supply....


Ah well I'm feeling peckish and need some much desired grease from working till 5 am last night - so I'm in the drive through at Wendy's getting a baconator! Did you know they come in 3 patty options?! Heart attack!


Ahhhh... The cholesterol special... I know it well, sigh.... :)


Lol thanks Dj. Here's what the robot looks like: User-inserted image He has 1 camera, and 3 HD servos. I read not to go past 12 volts, or below 2 volts. Any recommendations? This is my first robot ever. :)


What servos are you using? Hitecs like 6V... EZ Robot servos are good with 7.4v.... Do not use 12V or your Bear may experience the magical blue smoke... :P

BTW... The ezb4 itself is good from about 5V to 16V, but servos are generally good around 6V to 7.4V....


Wow he's so awesome! I'm fond of robots in fur for some freudian reason I'm sure.

My answer for power supply is quite complicated but simple - I encourage direct battery power. BUT, if you need a power supply, there are digital switching options to choose. Make sure it's enough amperage according to that tutorial I linked to.

Motors are unpredictable for power consumption because they are electro-magnetic and there's a pile of variables that are pretty much unpredictable without a degree in physics :)

So pick a real high amperage digital switching supply for 6-7v and use it :)


So for this project that you have a 7.4v 20amp power supply will work just fine... You could probably get away with 10amps, however you should get the 20amp version in case you want to add more servos or use it for another project that does use more servos....


Actually I would go with what @DJ suggests... Grab a bigger 7.4v LIPO from ebay... there are lots rated at 3000mah ~ 5000mah... Servos need power and you can't beat Lipos for being able to supply it...


No worries... We don't want to turn your bear into Smokey the Bear.... Have fun.... :)


Lol thanks. I did try a DC 6 volt adapter that I had. It made the servos move a little, but it didn't turn on the actual ez v4.


6V will work if the power supply is rated above 10amps or more.... Remember you need amps to run servos.... voltage between 6V and 8.4V should be ok.... 7.4V is ideal however...


If the ez-b didn't turn on, that adapter may have had the incorrect polarity. The polarity is positive (+) in the middle of the plug, and negative (-) on the outer side of the plug. The plug is actually called a Barrel Plug or Barrel Jack.

Most of the transformers that you will find around the house are not digital switching. They use a transformer, which is two wounds of wire at a ratio which conducts electromagnetically across the two and produces a lower voltage in respect to the wire ratio. What that means is, those transformers literally only contain a spool of wire that lowers the input voltage by a pre-defined ratio. Then a simple Diode is used to flatten one line of the AC current to produce simulated DC current.

In short, a transformer power supply is not a great selection to power a robot. A digital switching power supply is the best option - specifically one with providing between 6 and 8 volts DC current at more than 6-8 amps for your application. If you add more servos, the number of amps will need to be increased.

If you want to get crazy, use a PC power supply:) That's what we use!


Like a power cord that I have for my laptop? Mines a ac adapter that has an output of 19 volts and 3.42 A


You should buy this though....7.4v 5200mAh Lipo You can use the ez robot charger to charge it. It is a big battery that will last much longer than the 1300mA ez robot battery...


I use the basic 6 aa batteries. They last about 5 hours, so I think for now I'll get more to swap out. :)


Wow, 5 hours on the 6 aa batteries is great! I would not have expected that. I'm looking forward to seeing a video of your robot when he's ready!


Hello, all. In my old EZ-B version 3 of the robot, I used double power. Small power proper for EZ-board = + 7.4V 2800mAh & for the rest "power units: 6 servo, Cam, MP3, Light, 6 sensores" = + 11.1V 4000mAh + step-down DC-DC regulator +5V 6000mA. What about new V4? I'm trying to find the technical details about the new V4 robot. Correct Supply voltage, current consumption in rest (hold) mode, the maximum current consumption, etc. Where can I find this information? Another option is very important to me: What the average range of wireless communication in the home and outdoors?

Thanks for your attention.


Wifi has many options to extend it's range miles, along with being able to be routed over wired networks.


Dir DJ Sures, you write about your power servo 7.4V! Does this not reduce the service life of engines? I thought that this is the maximum voltage for small servo is 6V? (how I lagged behind you for two years! :-( ...


Hello, CochranRobotics! Thanks a lot for the tip on the documentation!


The HD servos are made to run at 7.4V. If you took a servo that was made to run at 6V and ran it at 7.4V, yes, you would reduce the life of the servo. These are not 6V servos running at 7.4V though. They are made to run at 7.4V. I have many of these running for about a year and a half of normal use at 7.4V without any issue.


Thanks for clarifying. On the one hand this solution is convenient and saves energy, on the other - forced to buy only the EZ-B servos.


You don't have to run the EZ-B from 7.4V. It can be run from 6V which would allow you to then use anyone's servos. You could also regulate the power off of each of the servo wires if you wanted to go 6V. Either way, your not locked into buying servos from EZ-Robot. This is a convenience that helped them to make their revolution robots without having to regulate power inline for them to work well.


Thanks for clarifying, CochranRobotics!