# OS error :Failed to write byte **URL:** \ **Category:** Support\ **Created:** [May 12, 2022, 2:52pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480 "2022-05-12T14:52:20Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![fff3x](https://avatars.discourse-cdn.com/v4/letter/f/c37758/32.png) [@fff3x](https://forums.pimoroni.com/u/fff3x)\ **Post date:** [May 12, 2022, 2:52pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/1 "2022-05-12T14:52:20Z")
Hey, I am running in to this error almost every time i use the pan-tilt hat and the servo’s doesnt even move. Anyone know any solutions to this? Traceback (most recent call last): File “/home/pi/track/facetracker.py”, line 37, in pan(cam\_pan-90) File “/usr/lib/python3/dist-packages/pantilthat/pantilt.py”, line 466, in servo\_one self.setup() File “/usr/lib/python3/dist-packages/pantilthat/pantilt.py”, line 80, in setup self.\_set\_config() File “/usr/lib/python3/dist-packages/pantilthat/pantilt.py”, line 118, in \_set\_config self.\_i2c\_write\_byte(self.REG\_CONFIG, config) File “/usr/lib/python3/dist-packages/pantilthat/pantilt.py”, line 209, in \_i2c\_write\_byte raise IOError(“Failed to write byte”) OSError: Failed to write byte ---
**Author:** ![Shoe](https://avatars.discourse-cdn.com/v4/letter/s/e36b37/32.png) [@Shoe](https://forums.pimoroni.com/u/Shoe)\ **Post date:** [May 12, 2022, 9:53pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/2 "2022-05-12T21:53:25Z")
[You aren’t Sreehar, are you?](https://github.com/pimoroni/pantilt-hat/issues/29) It sounds like you’re getting intermittent failure of the I2C bus. Is this a program you’ve written yourself? If so, do any of the default examples work? If not, how have you connected the pan-tilt to the Pi? ---
**Author:** ![fff3x](https://avatars.discourse-cdn.com/v4/letter/f/c37758/32.png) [@fff3x](https://forums.pimoroni.com/u/fff3x)\ **Post date:** [May 13, 2022, 3:13pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/3 "2022-05-13T15:13:05Z")
Yes same person. I did not write the code. Default examples shows same error. like this ![Pan-Tilt-HAT-intro](https://us1.discourse-cdn.com/flex016/uploads/pimoroni/original/2X/4/43513f67ac5d656637a39a5fa35461b1b8074509.jpeg) ---
**Author:** ![alphanumeric](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/alphanumeric/32/2729_2.png) [@alphanumeric](https://forums.pimoroni.com/u/alphanumeric)\ **Post date:** [May 13, 2022, 7:05pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/4 "2022-05-13T19:05:50Z")
That doesn’t look like Pimoroni’s Pan Tilt Hat? And if it isn’t, that’s why their code doesn’t work on it. ---
**Author:** ![ahnlak](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/ahnlak/32/5610_2.png) [@ahnlak](https://forums.pimoroni.com/u/ahnlak)\ **Post date:** [May 14, 2022, 8:38am UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/5 "2022-05-14T08:38:01Z")
Yeah, that looks like a [Waveshare Pan Tilt](https://www.waveshare.com/pan-tilt-hat.htm) (although it also looks like a product shot, so maybe they just grabbed the first vaguely similar thing off google to illustrate?) ---
**Author:** ![stven](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/stven/32/9105_2.png) [@stven](https://forums.pimoroni.com/u/stven)\ **Post date:** [December 1, 2024, 7:01pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/6 "2024-12-01T19:01:56Z")
I have the Pimoroni PanTilt hat and I am getting the same error. Any thoughts? 127.0.0.1 - - [01/Dec/2024 13:44:12] “GET /api/tilt/88 HTTP/1.1” 500 - Traceback (most recent call last): File “/usr/lib/python3/dist-packages/flask/app.py”, line 2548, in **call** return self.wsgi\_app(environ, start\_response) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File “/usr/lib/python3/dist-packages/flask/app.py”, line 2528, in wsgi\_app response = self.handle\_exception(e) ^^^^^^^^^^^^^^^^^^^^^^^^ File “/usr/lib/python3/dist-packages/flask/app.py”, line 2525, in wsgi\_app response = self.full\_dispatch\_request() ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File “/usr/lib/python3/dist-packages/flask/app.py”, line 1822, in full\_dispatch\_request rv = self.handle\_user\_exception(e) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File “/usr/lib/python3/dist-packages/flask/app.py”, line 1820, in full\_dispatch\_request rv = self.dispatch\_request() ^^^^^^^^^^^^^^^^^^^^^^^ File “/usr/lib/python3/dist-packages/flask/app.py”, line 1796, in dispatch\_request return self.ensure\_sync(self.view\_functions[rule.endpoint])(\*\*view\_args) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File “/home/steve/pantilt-hat/examples/pantiltweb/pantiltweb.py”, line 29, in api pantilthat.tilt(angle) File “/usr/lib/python3/dist-packages/pantilthat/pantilt.py”, line 496, in servo\_two self.setup() File “/usr/lib/python3/dist-packages/pantilthat/pantilt.py”, line 80, in setup self.\_set\_config() File “/usr/lib/python3/dist-packages/pantilthat/pantilt.py”, line 118, in \_set\_config self.\_i2c\_write\_byte(self.REG\_CONFIG, config) File “/usr/lib/python3/dist-packages/pantilthat/pantilt.py”, line 209, in \_i2c\_write\_byte raise IOError(“Failed to write byte”) OSError: Failed to write byte ![20241201_135034](https://us1.discourse-cdn.com/flex016/uploads/pimoroni/original/2X/b/bd60010370f8c43f4f26dcee432a098cbee937eb.jpeg) ---
**Author:** ![stven](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/stven/32/9105_2.png) [@stven](https://forums.pimoroni.com/u/stven)\ **Post date:** [December 1, 2024, 7:07pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/7 "2024-12-01T19:07:21Z")
I should also mention, I am testing this on a Raspberry Pi 5 with the latest 64-bit Bookworm OS. The I2C interface is enabled. Running everything in a virtual environment. Python is version 3.11.2. Python3-smbus is installed and is the latest version (4.3-2+b3) thanks. ---
**Author:** ![Shoe](https://avatars.discourse-cdn.com/v4/letter/s/e36b37/32.png) [@Shoe](https://forums.pimoroni.com/u/Shoe)\ **Post date:** [December 1, 2024, 8:13pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/8 "2024-12-01T20:13:41Z")
Maybe it is just the photo, but it doesn’t look like the pins on your GPIO extender are actually connecting with the HAT? They should slot into the holes in the black socket. ---
**Author:** ![stven](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/stven/32/9105_2.png) [@stven](https://forums.pimoroni.com/u/stven)\ **Post date:** [December 1, 2024, 8:34pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/9 "2024-12-01T20:34:50Z")
Ouch, you are 100% correct. Trying to add space above the active cooler, but I definitely messed up and made the standoffs too long and didn’t see it until you mentioned. I will fix that and retry. thanks ---
**Author:** ![stven](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/stven/32/9105_2.png) [@stven](https://forums.pimoroni.com/u/stven)\ **Post date:** [December 1, 2024, 8:53pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/10 "2024-12-01T20:53:22Z")
That was indeed the issue. The hat is working properly now. Many thanks! ---
**Author:** ![stven](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/stven/32/9105_2.png) [@stven](https://forums.pimoroni.com/u/stven)\ **Post date:** [December 1, 2024, 8:56pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/11 "2024-12-01T20:56:54Z")
![20241201_155453](https://us1.discourse-cdn.com/flex016/uploads/pimoroni/original/2X/d/db52d8049daae3284a436d2ed0a19202017274f8.jpeg) Fixed :) ---
**Author:** ![Shoe](https://avatars.discourse-cdn.com/v4/letter/s/e36b37/32.png) [@Shoe](https://forums.pimoroni.com/u/Shoe)\ **Post date:** [December 1, 2024, 9:35pm UTC](https://forums.pimoroni.com/t/os-error-failed-to-write-byte/19480/12 "2024-12-01T21:35:02Z")
I’m glad it’s working!