More than 50 android devices on same username/password I have between 50-100 Android devices.  They are being used as a sensor network. Another 50 are coming online soon.  The devices need to download an app from the play store.  So I need to login with a google username/password.  For now, I have been using the same username/password on all the devices.  However, now google is asking me to resign in to the devices after a week or so.  This didn't happen before.  I think the number of devices on the same account is tripping some alarm.

Does anyone have any recomendations for how to set up 50+ devices so that they are all able to download and receive updates from the app store?
Google Play won't let you do this. You can only have a few devices attached to each account at a time. This is to stop people abusing the facility of using paid content from any device on their account.

If the app is an open-source one, or it's under your control, you should distribute it to all your devices through a different mechanism (e.g. a custom app list on F-droid). Otherwise, you should contact the developer of the app and ask to make a volume licensing deal. Unless they're already dealing with enterprise customers, they won't be prepared for this situation, but I think most app developers will be willing to help you out for a reasonable bulk price.