Servo - Proper Setup

Hardware
1

Pardon the beginner question, but I’m looking for some help regarding wiring up a Tower Pro SG-5010 servo to my Photon.

Here’s the setup I had when my Photon got fried:

  • USB power from laptop connected to Photon
  • Servo + connected to Photon’s VIN
  • Servo - connected to GND
  • Servo Signal connected to D0

From my understanding, the USB is supplying the Photon with 5V, and this is being tapped into by the Servo via the VIN pin. Is the Servo likely drawing too much current and frying my Photon? If so, is there a better setup with the 5V USB power supply?

Thanks!

2

I would say the servo is drawing a lot of current and causing a brown-out on the photon. Also it will generate a lot of noise which will effect the photon too.

What is the photon doing now without the servo? is it getting hot or just not connecting? there are a couple of threads on how to get a photon going again after a brown-out

your best bet would be to power the servo separately. you could maybe use a usb power bank to help “buffer” the USB power, if the computer port can only deliver 500mA and the power bank can do 2100mA for phone/tablet charging you may be OK. might still need a extra filter cap or 2 close to the photon.

3

Currently the Photon is not connecting and unresponsive. All LED’s are off, and getting hot when connected to 5V via USB.

4

The Schottky diode SS3P3 that serves the power from the USB line to Vin is rated at 3.0A, therefore, unless the servo is under heavy load for long time, it should be fine from loading point of view.

The only problem you will get by blowing this diode is you no longer can supply power from the USB, you will have to feed the 5V to Vin directly. It should not affect other operations of the Photon.

Having said that, standard precautions as with any motor connection must be taken, including the use decoupling caps and fly back diode.

//Ed

5

With or without the servo connected?

6

Without the servo connected.

And thanks for the info! I’ll give it a shot.

7

Hi all, I’m also a complete beginner and trying to learn how to safely/properly connect a servo to my photon.

Here’s a Sparkfun link to the servo I own: https://www.sparkfun.com/products/9347

I have a photon, breadboard, jumper wires, USB powering the photon, and a servo model SM-S4303R (Voltage: 4.8-6.0 Volts)

Can I safely power the servo by connecting it to the photon’s VIN or is it a little more involved than that?

I’m a complete noob so I have no idea what terms like “brown-out”, “diode”, and “decoupling caps” are (did a quick google search).

Here’s a photo of the hardware I have:

Thanks!

kit.JPG3264×2448 1.35 MB

8

I have deleted your double post in the other thread since double posting is frowned upon not only in this community.
It might tie up multiple peoples precious time and does not help answering your request quicker.

Also consider if your post actually fits the thread you are in or if this is not considered thread-jacking (hijacking an other users thread).

Having said this, to your request
Looking at the servo you have, I’d say that you’ll probably want an extra power supply that can deliver enough current for the Photon and the servo seperately and I wouldn’t try to power the servo off Vin.

BTW:
@tstein, have you been able to get your Photon back to life?
And are you OK with the “thread-jacking” or should I split this out into a seperate thread?

9

Hi @ScruffR - unable to bring it back to life : /

And yes, happy to keep this thread going!

10

I guess your regulator is dead, due to overcurrent. If you still want to get your Photon back and feel up to the task, you could replace the regulator (and maybe protection diode).
But before you do that, you can see if your µC is still in tackt by supplying it via a relyable 3.3V source connected to 3V3 and GND (and no extra components added ;-))