Let's Make Robots!

power supply

hello everybody,

                         i am making a robotic hand with 5 servos .the servo is hxt900.i am also using some home made flex sensors which are made up of anti static poly bag strips and aluminum foil.sll the parts here require 5 volts.idont know how to provide energy to these thing.so i tried putting alligator clips and tried connecting them in parallel but only one or two work.the board is arduino duemilanove.how should i give them power please do something i am stuck in the middle of nowhere and i found lmr as light house on an island.

            i have attached a small photo it may help you and i tried connectin in parallel by connecting all the wires to alumium strip and connecting 5v to it but didnt work

2011-01-13-55582.jpg68.29 KB

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Please be more precise in your problem statement and read the LMR rules. The paragraph above is really confusing and the picture is too small. If English is not your first language break your paragraph into sections to make it easier to understand use headings like;

Current Setup:

Desired Function:


Attempted Solutions:

What is not working the servos or the sensors?
What is your goal? Have servos move when sensors are bent?

If the servos don't work you need to add an external power source because the board probably can't provide enough current. Run signal wires to the arduino and + and - to an external power source providing 5-6V. For the external power source connect batteries in parallel to provide 5-6V and connect ground with arduino ground. Parallel connections for servos means they each have a connection running to the external power source. Each servo has a + and - running to the + and - of the external power source.

i don't know how to connect in parallel.i tried extending wires from servo then connecting to the the alligator clip which is inturn receiving power of 5v from board but all are not moving when i bend it


I recommend using a solderless breadboard or soldering headers to a protoboard.  Bottom line- I think headers work best versus running wires to servo connectors.  So... hook up power to a breadboard rail and breakout power for each servo header.  Hopefully you understand, good luck

The hxt900 will take up to 6v, so try four AAs in a battery pack for them, and connect the grounds of the battery pack and other circuitry.  If you use rechargeable batteries you will get closer to 5v.

I suggest you read the part number of the voltage regulator you are currently using the 5v from (on your arduino I presume) and google for the datasheet to see what the max current output is.  Datasheets are your friend.

Even the batteries should have a datasheet, which should tell the max current discharge.  Read the specs or datasheet of the servo for the maximum current consumption, and multiply times five servos to determine what you need to be able to handle worst case (when all servos run simultaneously).  Note the servos should be in parallel to all get the correct voltage.