How to implement automatic shutdown in switch module and update homekit state

[ilovn]

I implemented a switch module through the code example, which controls the device through the gpio control output. Now I hope to automatically turn off 30 seconds after opening. I realized the shutdown through the timer, but I can't update the state in the homekit.

[shahpiyushv]

@ilovn You can maintain a pointer of the characteristic and update it as shown in this example. If you do not want to maintain the pointer, you can also fetch it at runtime using a combination of hap_acc_get_by_aid(), hap_acc_get_serv_by_uuid() and hap_serv_get_char_by_uuid, all of which can be found in hap.h

[ilovn]

When I use GPIO18 to control the relay to realize the circuit on and off, but updating the Homekit status still does not work properly, which UUID type with hap_serv_get_char_by_uuid or hap_acc_get_serv_by_uuid ? I got the aid from log,but hap_acc_get_by_aid still does not work.

[shahpiyushv]

Since your implementation is a simple switch, you just need to call hap_acc_get_by_aid(1). This pointer is created and returned by hap_acc_create() and so you can keep a copy of that too. Standard service UUIDs can be found here and standard characteristic UUIDs can be found here. UUID for switch is HAP_SERV_UUID_SWITCH, whereas that of outlet is HAP_SERV_UUID_SWITCH. The UUID for ON characteristic is HAP_CHAR_UUID_ON.

[ilovn]

Through the UUID or aid you provide, the code can run normally, but the switch status in the Home App remains unchanged.

[shahpiyushv]

Has iOS enabled the events? You can verify this by checking for prints like these in the serial terminal logs

Events enabled for aid=x iid=y

If you see this, whenver you call hap_char_update_val(), you should also see prints like

Value Changed
Notification Sent

You may also enable additional debugging using hap_http_debug_enable() once before calling hap_start() so that we can more logs to understand the issue.

[NguyenVux]

mine print out Events disabled for aid=x iid=y how can i enable it

[shahpiyushv]

Event subscription is managed by the iOS layer and is not in user's or accessory's control. If the serial terminal prints Events disabled for aid=x iid=y it means that iOS has explicitly disabled it since it is no more required. This typically happens when the Home app goes in background.