# Could not find a Cedrus device

**URL:** <https://discourse.psychopy.org/t/could-not-find-a-cedrus-device/1657>\
**Category:** Other\
**Created:** [December 18, 2016, 12:22pm UTC](https://discourse.psychopy.org/t/could-not-find-a-cedrus-device/1657 "2016-12-18T12:22:21Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Noa\_Slater](https://avatars.discourse-cdn.com/v4/letter/n/82dd89/32.png) [@Noa\_Slater](https://discourse.psychopy.org/u/Noa_Slater)\
**Post date:** [December 18, 2016, 12:22pm UTC](https://discourse.psychopy.org/t/could-not-find-a-cedrus-device/1657/1 "2016-12-18T12:22:22Z")

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Hi,

I have installed PsychoPy 1.84.2 and trying to run a small testcase experiment using Cedrus box.

I have downloaded the FTDI drivers and can see the box as “USB Serial port” in the device manager (COM3)  
I downloaded pyxid and put it in Lib/site-packages/

but when I run the experiment I immediately get  
3.2445 ERROR could not find a Cedrus device

Is there any place where I can define in PsychoPy where my Cedrus box is connected (COM3 etc ) ?

I tried in Win to move it to COM4 but the same error occur.

If anybody have suggestions I’d be very happy 🙂

Thanks!  
Noa

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<div class="post-metadata">

**Author:** ![Noa\_Slater](https://avatars.discourse-cdn.com/v4/letter/n/82dd89/32.png) [@Noa\_Slater](https://discourse.psychopy.org/u/Noa_Slater)\
**Post date:** [January 12, 2017, 11:53am UTC](https://discourse.psychopy.org/t/could-not-find-a-cedrus-device/1657/2 "2017-01-12T11:53:49Z")

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anybody has an idea ?

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**Author:** ![MCR](https://avatars.discourse-cdn.com/v4/letter/m/51bf81/32.png) [@MCR](https://discourse.psychopy.org/u/MCR)\
**Post date:** [January 12, 2017, 12:34pm UTC](https://discourse.psychopy.org/t/could-not-find-a-cedrus-device/1657/3 "2017-01-12T12:34:37Z")

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Hi Noa,

I have recently got a cedrus box working and had to get through a similar set of problems. I also have it in COM3.

If you haven’t already have a look at the github page for the cedrus box: [https://github.com/cedrus-opensource/pyxid](https://github.com/cedrus-opensource/pyxid)

Try running this script in psychopy and see if it works.

```
import pyxid

devices = pyxid.get_xid_devices()

mybox = devices[0]

if myBox.is_response_device():
    myBox.reset_base_timer()
    myBox.reset_rt_timer()
    while True:
        myBox.poll_for_response()
        if myBox.response_queue_size()>0:
            response = myBox.get_next_response()
            print response

```

This is what I use to see if the box is working correctly before putting it into an experiment. Let me know what happens.

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**Author:** ![Noa\_Slater](https://avatars.discourse-cdn.com/v4/letter/n/82dd89/32.png) [@Noa\_Slater](https://discourse.psychopy.org/u/Noa_Slater)\
**Post date:** [January 29, 2017, 11:19am UTC](https://discourse.psychopy.org/t/could-not-find-a-cedrus-device/1657/4 "2017-01-29T11:19:30Z")

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I downloaded pyxid from Cedrus. But when I ran your code - it seems that PsychoPy uses a different package which I cannot locate. When I run “import pyxid” I see that it uses this package:

\<module ‘pyxid’ from ‘C:\Program Files (x86)\PsychoPy2\lib\site-packages\pyxid-1.1-py2.7.egg\pyxid\__init_\_.py’\>

I do not have any directory names ‘pyxid-1.1-py2.7.egg’ in this location!

I do have “pyxid” which is the package I downloaded from Cedrus.

How can I tell PsychoPy exactly which package to import and how come I have files I cannot see ?

Thanks!!

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**Author:** ![JonB](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/jonb/32/604_2.png) [@JonB](https://discourse.psychopy.org/u/JonB)\
**Post date:** [June 27, 2017, 7:19am UTC](https://discourse.psychopy.org/t/could-not-find-a-cedrus-device/1657/5 "2017-06-27T07:19:48Z")

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Did you use one of the packaged versions of psychopy? There was a problem with the bundled version of [serialio.py](http://serialio.py) (or possibly [serial.py](http://serial.py)) that stopped me being able to connect to a Cedrus LSC-400. I tried downloading a newer version, but ended up building 1.84.2 myself, which pulled down an updated [serial.py](http://serial.py) and this fixed it for me. I’ve not tried the bundled 1.85.x install to see if the fix is in there, but I imagine this should be fixed by now.

Best, Jon