i know those are the servos too because i bought them for
$10.47 and i am also just about done with the one of the legs :slight_smile:

is an image of the left leg

it took me such a long time to make them because i had to make the brackets from scratch :smiley:
but the bright side is that its very balenced
and also light weight :wink:

funny thing about this leg it is only 2.27"X1.16" so its not even 3" all
and the oraginal brat Jr. is how big?
i’m geussing about 7-8" tall but thats just geuss i want to here what you think

…so any questions or answors :astonished:

the original Brat Jr? id say he was more like 4-4.5 inches tall
then the BRAT is about 6-6.5 in tall

Well. wowy7, you don’t lack enthusiasm. lol
I like you idea but the 8 gram servos you have, will not work for a biped. Sorry but they are cheap and will strip, if they have enough power to even function. I’ve used them before in micro helis and regretted it. If you are serious about making a micro biped, there are a number of good micro servos out there.

GWS Pico and Naro series. Some are better than other. The Pico std’s have some trouble centering and are very easy to strip. The Pico BB’s are a bit bigger and a little tougher.
The Naro std is a joke. No good. The Naro BB+ is not bad with decent power and the Naro Max+BB is a very decent servo. With the Naro Max the size is comparable to a Hitec HS-82 and it has decent power and good centering.

Hitec and JR make some of the best micros, in my opinion. I’ve used the JR micros to actuate the air valve for the retracts on my .50 sized Airwolf Helicopter (4 1/2 feet long). They are reliable and the accurate plus there are metalgear versions.

Hitec’s HS-55 and HS-82 are very popular among the micro and mid sized heli guys. They are worth every penny. And the metal gear and high torque versions can be as powerful and durable as any standard servo.

Stay away from Walkera brand servos. They are garbage, don’t center, and are jittery as heck.

I’d like to see more pictures of your leg. Looks interesting. Good luck with the project. And be sure to take these guys’ advice. They have been around the block with Bipeds and other robots and they are only trying to help you, not discourage you.

well well well… it looks like most of you are wrong
vary wrong because i used a test program and it is so strong that it made the whole leg and body fly into the air :open_mouth:
all right im not quite sure yet because im not done the other leg yet but im hoping it will work with both leg’s so… any ways now for the batteries what are the most light weight batteries im geussing…ok so i don’t know :laughing:

:unamused: Ok

Well, I would guess it won’t last. Only a matter of time before they start stripping and heating up. Or not centering. I was only trying to help you by discouraging buying more cheap servos for an application they aren’t suited for. Unfortunately, with servos, you almost always get what you pay for.

The lightest batteries would be Lithium Polymers, or Lipos but for some reason I feel reluctant to recommend them.
They have to be charged by a Lipo specific charger. You can NOT cut corners with this and use just any charger. A few small cells or pack and a charger would run you the same as a few HS-82 servos. You need to match the amp draw to the cell capacity and C rating, and be sure never to over-discharge them below 3.0V per cell or over-charge them.

yea, i agree with evolution here. they are very light weight and have an excellent power weight density, but thery are very unstable

like he said, you need a specific cahger (50-a LOT, depending on how good or crappy you want it, also there is the misfortune of needing a DC power source such as a car battery of a DC transformer, because you cant just plug the charger into the outlet and as you know car batteries are not cheap along with DC transformer power sources 65+ dollars

if anything, id go with some AA or AAA rechargeable batteries NiMH, and you will also have to find a way to fit them onto a frame of that size, very small form factor…the SSC-32 will it and the Bot Board, all will need tiny about 2 2/3 X 3 in for a home (not sure about the exact size of board, someone lend a hand if you know, but i know thats close)

o well, see what you can come up with :slight_smile:

what the difference with AA & AAA arent they both 1.5V?
are they different because of there mAh?

the batteries are smaller for 1

yes, the AAA are smaller than the AAs but there is a lower mAh, so thats a down fall

is the mAh how long the batterie(s) last for?
because i don’t realy know much about batteries.

ok… so maby i do know a little about batteries
but not everything :laughing:

it’s capacity. sort of like the size of the gas tank and how big the pipe coming from it all rolled into one.

1000 mAHr is 1000 mili-ampere-hours, could also be put as 1 AHr or 1 ampere-hour. As the units imply you can very roughly expect a 1 AHr battery to be able to deliver 1 ampere for 1 hour, or 2 amperes for 1/2 an hour. That’s where the size of the gas tank bit comes in.

The how big the pipe part is usually the smaller a battery is the less current (amperes) it is capable of supplying. Usually this is expressed as a “C” rating times some multiple. So a 1 AHr NiMH battery might be rated to deliver 5C, or 5 amperes maximum. If you try to take more you risk damaging the battery. Of course considering the information in the previous paragraph, if you pull 5A from your 1 AHr pack it’s going to last at most 12 minutes, and in reality probably more like 8 to 10 minutes.
Ok, so the last thing you need to get a taste of is that not all batteries are created equally. a AAA Alkaline will deliver much higher mAHr, once, than say a AAA NiMH will repeatedly. Even two different manufacturers AAA cells of the same technology may be rated very differently. You have to read the data for what you buy and understand what your needs are so you don’t buy and burn by trial and error.

Finally if you are silly enough to mess with LiPo cells before you really understand these things you will learn that “burn” is a very literal term. Discharging LiPo packs too much will damage them and reduce their capacity. Charging them at too high a rate, easy to do if you’ve damaged them and don’t know, can actually cause them to get hot enough to ignite. Here’s the ticker… you can’t put the fire out until it burns itself out. google LIPO FIRE and find out that, while it certainly is safe enough to use LiPo batteries if you know what you are doing and handle them carefully, not understanding how they work and what their limits are can be a very expensive learning curve. :wink:

batteries and battery technology is really cool stuff. once you grasp the concepts and understand the terminology you will appreciate them even more.

Have fun!

ok tomorrow i will be completly done with the body
cause i didn’t get the servos last week so i am gettiing them this satarday
also chech this out i used rechargable batteries that ii got from allelectronics
i got two AA batteries and the mini can hold them up just fine
but the only problem is that i can’t find out how to charge it

so can somone that knows a LOT… about batteries than tell me what to
do :unamused:

Unless I misread your post, 2 AA’s won’t be enough to power your servos. You will need 4 rechargable AA’s to power them. Micro Servos on 2.4 Volts will have almost no power, or they may just chatter and gitter.

what do you need to know about the batteries?

Beats me… :open_mouth:

If you don’t know how to charge 2 AA’s, you need to take a step back and learn a few things about batteries. It will help you out alot when planning on how to power your robots.

Here are the basics on the anatomy of a common battery:

Here a few different types and how they can be assembled into parallel groups, for higher capacity, or serial groups, for higher power:

And here is a great link to all kinds of battery information from how to charge NiCD, NiMh, Lead Acid, Li-ion, Li-poly, etc batteries to how they work:

Find out if your cells are NiCad or NiMh. It makes a differenece in how you should condition them and maintain them. And you will need 4 cells for your robot.

All the answers to your battery questions are in those pages.

ok my brain just hatched an idea :bulb:
know iv figured out that a nine volt is smaller and lighter than two AA

but theres somthing i don’t know yet…are nine volts enough to power four micros :unamused:

A nine volt is a good way to burn up four micro servos.

Remember just a few posts back, when you were warned against applying more than six volts to a micro servo? Nine is greater than six.

A 9 volt is too much voltage. And not enough capacity. Those are tiny batteries and in most 9 volts, the capacity is very small.

You need 4 AA batteries in series. Or AAA’s if you need to save the weight.
You need 4 of them.

You are shooting for around 4.8 volts. Even 6 Volts may push a low cost micro too far. And 2.4 volts is not enough.