Running a Closed Loop System
Confirming Pick-to-Light Picks
Running a closed-loop system lets your server know whether the picker acknowledged the pick-to-light pick to light task.
Modern devices support barcodes and QR-Codes that are a natural choice for transaction confirmations. In fact, the encoded data can be customized for each individual pick.
These options are unavailable on Voodoo Robotics Classic devices. For Classic devices, users must set up their servers to receive feedback information.
Callback Confirmations
For modern or classic device users that need callback confirmations, there is a hidden parameter that the user can add to the QueryString URL, called a transaction ID. (The REST API also supports this parameter.)
https://www.voodoodevices.com/
The user chooses a transaction ID (a random number, a counter, or a nonce) to identify the particular call to the device. (The REST API simply refers to this parameter as ‘nonce’.)
If using a URL for device calls, then, after the picker presses the button on the device, voodoodevices.com makes a URL call to your server including the transaction ID like this, using “transactionID001” as an example, with an ack:
https://your.domain.com/voodoodevices/transactionID001/ack
If the picker does not press the button (within the time limit specified in the initial URL call), voodoodevices.com makes a URL call to the server like this with a nack:
https://your.domain.com/voodoodevices/transactionID001/nack
If the device was out of range, or there was some problem communicating with the device, voodoodevices.com does not make a follow-up URL call.*
The server receives one of the following:
- An ack message, indicating that the picker pushed the button
- A nack message, indicating that the device timed out
- No response, indicating that the device is out of range or some other problem *
The prefix of the response URL above, https://your.domain.com/voodoodevices/…, is a preapproved string you choose and that we set manually in voodoodevices.com for your account. The URL prefix can be anything you choose, using HTTP or HTTPS. Contact us to register your URL.
Warning: Should you choose to use a Closed Loop System setup, you need a very reliable communication system between your server and voodoodevices.com on the cloud.
* After we designed this system, some customers expressed a desire to get a response back to every request. We therefore added a feature that can send back a ‘lost’ message for devices that does not produce an ack or a nack. Just let us know if you would like us to enable this for your account.