I'm doing a robot arm for a project, but programming has become the least of my problems.

I don't know how to connect the servo motors. I have a power module that apparently has around 5 V of output (approximately, but if you see the image, it may be different, as you see I don't have experience). Each servo uses 5 V (approximately), and I'm using 4 of them.

My first problem is that I don't have enough voltage to power the servos, at least not simultaneously. The thing is that I have no idea how to use a power module or what is more convenient, I don't even know if 5 V even works because with the same power supply I managed to move two.

My other problem is that even if I had a proper power supply, I would not know how to connect it. The servos have female headers and I have male-female jumpers and I have no experience soldering, but I could do it.

The thing is that most power supplies don't always have clear labeling on the output. My ultimate goal is to end up with four male pins with 5 V each. This might be a very weird problem but it's seriously hard considering buying something you don't know how to use.



Dimension: 40mm x 19mm x 43mm

Connector Wire Length: 300mm/11.8 in

Weight: 56g

Operating Speed : 0.17sec / 60 degrees (4.8V no load)

Operating Speed : 0.13sec / 60 degrees (6.0V no load)

Stall Torque : 9.4 kg-cm (4.8V)

Stall Torque : 11 kg-cm at (6V)

Operation Voltage : 4.8 - 7.2Volts

Gear Type: All Metal Gears

Connector Wire: Heavy Duty, 11.81" (300mm)

Current power supply

Specifications: Unknown

I'm also using an Arduino Uno for this project, but nothing is directly connected. Just in case.

  • \$\begingroup\$ For a full answer it would help if you'd edit your question: take a close-up picture of your servo's connector, or tell us what order the wires are in. I think it's red-white-black, but I can't be sure. \$\endgroup\$
    – TimWescott
    May 5, 2023 at 4:05
  • \$\begingroup\$ It's a shame you photographed the side of the servo without the sticker full of information. Can you show us that label? \$\endgroup\$ May 5, 2023 at 7:54
  • \$\begingroup\$ I already edited the question \$\endgroup\$
    – Akko
    May 5, 2023 at 16:13

3 Answers 3


You need to do a bit of studying until you understand the difference between hooking up something in parallel and hooking up something in series. Then a bit more to understand the difference between voltage and current.

In the mean time: when you have a voltage source (like your power supply) and you connect multiple loads in parallel to it, all of the loads will see the same voltage. On the other hand, the current used by each load will add together, and that total current will be what the source needs to supply.

So you do, in fact, have exactly the right number of volts to power all your servos, and possibly your computer, too.

Typically the way you'd power your servos is with a block of 3-pin connectors, one per servo. The center pin of each connector is ground, one of the end pins is +5V, and the other pin is signal. I can't quite see the colors on your servo, so I can't tell you which is which, but the center wire is ground, the power wire will probably be red, and the signal wire is whatever is left over.

You want to use connectors with .025 inch square pins on 0.100 inch centers. That's a very common size, so you should be OK finding them. It'll be convenient to get some pad-per-hole vectorboard to solder them into, then you can run one wire to all the ground pins, one wire to the +5V pins, and one wire each to the signal pins.


Here's a picture of a pin block for attaching servo motors (highlighted with black box). This was done on veroboard with a breadboard style layout.

enter image description here

Colored lines show electrical connections. Each brown/red/orange row in the 3x3 block is for plugging in a servo motor. Brown(gnd/0V) and red(+5V) columns are connected together to connect each red/brown servo wire to the power supply. The top pins in the brown/red rows actually connect the board to the 5V power supply. Each orange row connects an orange servo PWM pin to a PWM output from the microcontroller connected.

To drive a bunch of servo motors without building any board, just take two pin headers with as many pins as you have servo motors and solder a wire across the pins to connect them all together.

enter image description here

Make two of those to connect the columns of brown and red pins on your servo connectors together. The wires soldered across the pin headers should be connected to the 5V and GND. If you cut one end off a jumper wire and strip off some insulation, you can plug the remaining end into one of the Arduino power supply pins. Alternatively, use pin headers that have 1 extra pin and use that to connect to the power supply.

This leaves the connector holes for the orange wires exposed and you can use male-male jumper wires to connect those to digital pins on your Arduino UNO.

For more compactness, you could also use another pin header to connect the orange PWM pin holes to the female header on the Arduino. Normally that would mean using headers with extra long pins meant to bridge between two female holes but a normal pin header works okay if the metal pins are pushed through the plastic a bit so there's about the same length exposed on both sides.

enter image description here


I think you can use a servo driver like the PCA9685. By using a PCA9685, you can control 16 servos together with a single Arduino UNO. Most servos are designed to run on about 5 or 6v. Keep in mind that a lot of servos moving at the same time (particularly large powerful ones) will need a lot of current. Even micro servos will draw several hundred mA when moving. Some High-torque servos will draw more than 1A each under load.


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