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Topic: 24 motor array (Read 938 times) previous topic - next topic

sniperguy455

hello, this is kind of a large question and i would appreciate if any one who answered it could be as specific as possible.

I'm a freshman college student and for my job my boss asked me to make a small motor array made up of 24 servos.  For this project i need to be able to control each motor individually (via a laptop of something along those lines) and make them turn both forward and backwards.  Also, i want them to only rotate at about one revolution a second or less, and i want to try and keep the prices relatively low even though i do realize that this will cost probably a couple hundred dollars.  I was thinking that i would need an h bridge, an arduino micro controller, servos, wires, and some batteries.  Unfortunately, i don't have a whole lot of experience with this kind of thing and i realize i probably don't know of all of the things i will need.  Also, I'm not exactly sure How many motors i can hook up to an arduino micro controller and h bridge or even if i necessarily need the h bridge.

I would really appreciate it if someone could give me a list of good products to buy to build this array at an affordable price( and the quantity of each part) while also helping me determine how best to set this up. 

(shortened version: i need to control 24 servos individually and wirelessly while having the ability to adjust the speed of rotation forward and backward and i need a list of components that i will need and preferably some info on good products, vendors, and manufacturers)
Also, i need to waterproof it but i feel like that's something I'll have to do separately.

If you have time to help me out thank you very much.

MikMo

Do you really mean servos, they usually only rotate 180 degrees ?
Do you need full rotation or just, less than 180 degrees back and forth movement?

H bridges are usually used for DC motors not for servos. If what you really need is DC motors you will need geared motors to get 1 RPS, an you will need one H bridge for each motor if you need individual control over speed and direction. Geared motors that go down to 1RPS = $$$

Do you need individual speed/direction control over the 24 motors?

Wireless control over what distance ?

When you say "waterproof it", will it be submerged?, because that will have an influence on wireless options.

Have you considered your powersupply needs?, if what you really need is DC motors, you are going to need a beefy powersupply to run 24 of them.




holmes4

Go back to your boss and find out what this thing is in tended to do. At the moment your trying to get us to help you implement a solution (24 motors with Wifi).

My first pass at a design to do this is 6 Uno's linked using the built in I2C with each Uno controlling two dual motor controller shields (4 motors). One of the Uno would be the master and would have a wireless/SD or XBee shield with a WiFly bug used in place of an XBee.

so if I where to give your boss a quote for the hardware it would look something like

12 x Dual motor controllers @ 26 GDP each = 312
6 x Arduinos UNOs @ 22 GBP each = 132
1 x wireless/SD shield @ 21 GBP
1x WiFly @ 32 GBP

total so for 479 GBP
plus 24 motors @ who knows what as we don't know what your trying to do. Plus software design.

plus and extra 20% for bits and bobs.

Mark

HazardsMind

Created Libraries:
TFT_Extension, OneWireKeypad, SerialServo, (UPD)WiiClassicController, VWID

sniperguy455

I do know all of the specifics of the project that i should be able to answer any specific questions as you're trying to help me.

so the array is going to be placed in an high grade incubator(due to really high humidity water accumulates on the parts)  meant for cell cultures and things like that.  So it has to be able to transmit through a metal housing but past that only about 5 feet

Also, as i said before i need it to be able to rotate really slowly while being easily controlled.  These motors have to be very small (servo was the only thing i could find that was small enough but a dc motor that size would be fine.)  these motors will be rotating a rod with a ball bearing at the end in order to roll along a prefabricated rail and all 24 motors will be going along their own rail,i only need to to be able to maybe turn somewhere around 720 degrees in either direction since the rails are pretty short.  This is the reason why i need pretty precise control over the motors and also why i have to be able to control each one individually otherwise they  would shoot off the rails.  

Also, i was wondering how many motors i could hook up to an arduino, i saw one guy do 10 by using a breadboard somehow and i think minimizing the number of arduinos could help cut back on costs.

As you can see i don't really now a whole lot about servos and motors but i thought i would have to just wire some batteries in there to help run it.

That 32 servo controller also looks like it could be a great help if it turns out that i can use servos thanks.

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