This is based on an E32R40T ESP32 4.0" resisitive touch CYD variant. Just two more components are needed: an FM-505 Fonkan UHF reader (1dB is fine) and a PN532 NFC reader in I2C mode. Place UHF tags inside or somewhere with little wear in/on the things you want in the renting system. For the initial collection of tag IDs to add them to the MakerSpace API have a look at the esp32rentalalert project.
Users need to be authorized for rentals via MakerSpace API first. Therefor they need a name linked to their account. This can be done by the OIDC selfservice on NFCKasse or manualy via the admin interface if you know the tag ID.
A user checks in on the rental station using their tag. They can then decide to rent or return items.
In rental mode each scanned item will be added to the list. If an item is currently rented by another user but not marked as returned, the item will get highlighted. The user can delete items from the list, if they were scanned by accident (placed too close to the station). If deleted from the list, the item will not get added again, so if (even though there are proper dialogs in place) the user deletes the wrong item, they first need to finish the current rentin process and start a new one afterwards. The rental of all scanned items needs to be confirmed by the user.
In return mode items scanned will automatically be marked as returned, but only by the person that actually rented them.
Both dialogs will stay open for a definiable time (5 min after last action by default), so make sure to hit confirm rental or logout. The rent/return window will close after 30s if nothing is selected.
The display comes with cables 4p JST1.25 <> 4x Dupont and 2x4p JST1.25, while the UHF reader ships with a 5p JST1.25. For the UHF reader you need to repin the JST from 4p to 5p with the EN pin left open. Use the UART connector on the display board and connect Rx/Tx crossover to the UHF reader. Close the R1 trigger input of the module for permanent read activity. Remove the 100R resistor closest to the UART port and replace it with a bridge, as otherwise the CH340 will win the serial line. You may rip the serial traces to the CH340 open after successful programming (remove the reader first) and continue with OTA flashing. Make also sure to setup the reader for your region and signal strength before closing R1 on the reader.
The JST<>Dupont cable can be used as is to interface with the PN532 board via the I2C port. Just make sure to set the switch on the regular red boards to on/off for I2C mode.
The case is designed for a 1 dB 35x35mm UHF module, the CYD and the NFC reader with plenty of space inside. CYD and NFC reader are held in place by a total of 6 M3x3 4.2mm heat set inserts with M3x4 screws, while the UHF reader simply slots in. The back is mounted also with 4 M3 inserts, but these can be longer. Wall mount with two 4mm countersunk screws.