Hello, I made the leap after a fair amount of research and bought an ezbv4 last night. My initial application is static so I deferred buying a battery..unless I missed it I did not see a wired power adapter in the store. I have read some of the power tutorial.. I did get the power base also.
I am looking for a recommendation on finding a power supply.
I expect to eventually run 18 micro servos and possibly up to five brushed motors. Three of these are larger and draw 1.8a stalled.. I never expect to have all the servos running at once.. I plan to have the. Brushed motors running through escs so their power can be drawn from another source. If you follow.
I want to make sure I have something soon.. So to start I could use a dc wall wart say 12 volt 2amp with 2.1 mm barrel?
Can someone throw out some links to recommended sources? I am inclined to go to one of the mote prominent online robot shops. Does that make sense?
The digital ports on the EZ-B V4 are not regulated. Unless your servos are 12 volt servos, or you are willing to run these from a different power source or through an UBEC or some other regulator, you probably dont want to use the 12 volt power supply. I will add more in a bit. busy at work. i just dont want you to blow up yours servos.
Hi! Welcome to the forum
First, when you say "not all servos are r running at once". What does that mean? To clarify, are you saying that you will Release the servos? Or they won't be "moving" at once? Because how a servo works is not like a regular motor. When a servo is "holding position", that is a stall torque + holding weight. A servo, even when not moving, is actually using a great deal of current holding position. This is of course when holding weight. A servo in position that is not holding weight, won't be using much current because the motor isn't running to hold the weight.
That's the difference between a servo and a motor. Forgive me if you actually meant that the servo will be released and not receiving a PWM signal to hold position. Many people are lost when it comes to servos. Here's a tutorial on how a servo works (the learn section is your friend): https://synthiam.com/Tutorials/Lesson/48?courseId=1
As for the power supply, 2 amps won't be enough for much - maybe 2 servos. Unless the power supply is a switching supply, because most are transformers which are made for transistor circuits. There is a wack of information on this forum about power supplies to use - and user tutorials about them. Now, the biggest challenge you'll run into is assuming a "wallwort" can provide current for anything mechanical, even if it has a kabillion amp rating.
This is because transformers, again, are generally designed for transistor circuits - and the load of a mechanical device (Such as a motor or servo motor) will affect the whole circuit. It's inherit to how a transformer works - this is why switching power supplies have been invented (and due to lower power consumption/heat)
Here's Steve's tutorial: https://synthiam.com/Tutorials/UserTutorials/163/1
Here's techno's tutorial: https://synthiam.com/Tutorials/UserTutorials/170/1
There may be some others, look here: https://synthiam.com/Tutorials/UserTutorials/
Also note. as dave cochran just mentioned - the EZ-B ports aren't regulated. This means power in is power out. You will find out more by reading the EZ-B v4 datasheet, it's in the learn section as well. Here is a direct link to the ez-b v4 course: https://synthiam.com/Tutorials/Course/5
@kennard42 A 12V 2amp power supply will be woefully inadequate for what you want to do... You need to start looking in the range of 12V 20amp (probably higher) power supplies...
I have a Meanwell 5V 60amp power supply that is barely able to power my inMoov. On occasion I still get browns out causing the ezb to reboot....
@STEVE G 's Tutorial
and the basic learning lesson Lesson 13
@Richard, you need to throw some super capacitors on the inmoov like we have done. it's great and never get a brownout!
@DJ.... Yeah I know.... Jeremie already told me to to it while I was visiting you guys at ez robot back in May... Been meaning to, but been lazy about it...
The biggest thing is that you need a 5-7.4v power source depending on the voltage of your servos, as the ez-b is unregulated, so what goes in comes out. Any sensors would then need to be regulated or powered from a different source of it can't take that voltage. Your power source needs to be able to supply the stall torque of each motor/servo motor combined, plus enough for sensors and 100mAh or so for the ez-b. So with that math, about 30A but that's close, and almost no power supply can output what they say. I would get a power supply that can output close to 40A easily.
Lots of great info. I think I am getting it and will study those links. I am a noob to all this. Obviously. Much of my reading had been on arduino and when they showed all these servos running they didn't mention power much.
So, I only have a couple servos to play with and a servo tester. Specs on the servos are hard to come by. Can't find how much the 'inrush' draw might be let along operating draw. These and the ones I have looked at seem to be 3-6v, so based on that and comments here and more reading I see I really want a 5v or 6v supply MAX?
Here's one servo I was looking at: http://www.hobbyking.com/hobbyking/store/__22927__HXT900_Micro_Servo_1_6kg_0_12sec_9g_US_Warehouse_.html
and I think I may end up needing a second supply then for the brushed motors I want to run with the ESCs.
Here is the ESC: http://www.hobbyking.com/hobbyking/store/__9090__Turnigy_20A_BRUSHED_ESC.html
Looking at this 5V:
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&productId=123394&catalogId=10001&CID=MERCH
It's half the price of the EZB.
A lot of these say 'single' output but it looks like they have seven screw terminals. The picture is kindof small but it looks like two V+ and V- but can't make out the others. Note says picture may not be exact. Datasheet does not clarify that aspect.