Cameras keep getting disconnected

[radbot]

I ordered a C270 and an Andonstar. When the C270 arrived, the box says it cant focus closer than 40cm (15.7"). Today I ordered a c525 (printed on the c270 box) for $30 delivered, which says it can focus as close as 7cm (2.7"). The Andonstar was $70 delivered....

Can you please post a pic of how you mounted your Andonstar?

I wonder if buying a really nice internal usb hub / power supply is in order to keep the factory cameras connected. We use a hub that is connected to the wall power, but it just wouldnt stay connected. We also tried this with the cameras plugged directly into the desktop. Hopefully this $100 upgrade will solve the disconnection problem. Thanks for your specifics. I will certainly update this post if we have problems with either device for future readers.

[mrandt]

Hi radbot,

IMHO the C525 is not a good choice. It has a motorized auto focus which will likely interfere with computer vision unless you either disable it in hardware or find a way to hack the driver.

While the stock C270 might not focus on close objects out of the box, it is well capable with a very simple mod:

Open the case (screws and clips) and you'll see that the lense has a thread to adjust focus by turning the ring. It is usually fixed with a dot of glue; easily removed with an exacto knife or similar tool.

You can then easily adjust focus as needed.

I suggest to remove the camera PCB from its housing and make an alternative mount for it.

If you have a 3D printer, you might want to check out the STLs for my upcam mount which I shared here:
http://malte-randt.de/improved-3d-print ... era-mount/

I desoldered the microphone and the green "recording" LED from the boars - but that is optional.

To mount the Andonstar camera a good option is a linear rail mount for 12mm diameter rods. You can get them with mounting holes that fit the original camera mount location in Juha's steel plates.

I use Misumi part SHSTA12-15:
http://uk.misumi-ec.com/vona2/detail/11 ... SHSTA12-15

I used a 3D printed Mount for my down camera at first but it was not rigid enough. Even tiny movements (i.e. flexing / bending) of the camera relative to the head causes accuracy issues. So a sturdy aluminium Malte seems a better solution.

Regards
Malte

[Mark Harris]

USB is a pretty fickle protocol.. it REALLY doesnt like noise. I used to have a CNC router who's VFD spindle spat out a lot of EM and electrical noise into the power line (despite all shielded cables and such), it would disconnect every usb device from every computer in my house on power up. I added a powerline filter to the output and used high quality shielded USB cables near it, and all my problems were solved.

Now, LitePlacer doesn't have a VFD to ruin your AC power.. but it does have a lot of stepper motors that create EMI. You might want to consider hacking your cameras a bit, open them up and replace the most likely poorly (if at all) shielded cable with a good quality shielded cable (finding the thickest, least flexible, expensive USB cable at your local electronics store is usually a good bet.. or build your own). Just desolder theirs from the board and resolder your new one after cutting the plug off Also add a big decoupling cap to the powersupply at the camera, and ideally a ferrite bead in series with VCC going to the camera's board (if you add a ferrite, put a big cap on either side to make a Pi Filter). Make sure you have a good quality shielded cable going to your USB hub, and hack it to add extra power decoupling.

I would hope that all your stepper motor cables are shielded, or double shielded (foil + braid), as this will help significantly too!

You might also want to consider a line filter on the AC power of your liteplacer, they are pretty cheap and it won't hurt anything

[baerwind]

I also had problems with one if my cameras.
You can check that with
https://msdn.microsoft.com/en-us/librar ... 85%29.aspx
Grouping by USBDevicePortPath and USBDevice shows resets and reconnections of the cam with multiple DeviceIDs.


Replaced with a refocused Logitech C310, -> fine.