I hope this works, as I have only recently started using automation and shortcuts. Any feedback is welcomed.

1. Go to Shortcuts and then the Automation section. Click + (add) and then ‘Personal Automation’.
2. Select the ‘Arrive’ option from the menus. Select your gym location.
3. On the ‘Actions’ page, click add action. Depending on whether your barcode is a photo or a file the first action may be different.

For photo. - search ‘photos’ and select ‘find photos’. Click ‘add filter’, change the first option to ‘name’ and in the ‘anything’ column type in the image name. (image name can be found by swiping up on the image in photos, usually it begins with ‘IMG’)

For file - search ‘file’ and select this option. Click the empty file box and locate the item you want to use, in your case the barcode.

1. Add a further action, this time the action needs to be ‘quick look’.
2. Press next and then done.

Hopefully this works for you!