@lubker - I have been working on proving out the instructions for running the local cloud on a Raspberry Pi 3 setting that up as an access point. I finally have it all working and can say that Photons do a time sync against the local cloud. I don’t know what sort of latency you will have between the Photon and RPi3.
I am using the stock spark-server and spark-protocol. There is one small patch to perform in the spark-protocol code noted in my instructions. There is a lot of patches floating out there. At this point it is sufficient for the device to connect to the local cloud and obtain the cloud time – from the RPi3.
$ particle serial monitor --follow
Polling for available serial device...
Opening serial monitor for com port: "/dev/cu.usbmodem1411"
Serial monitor opened successfully:
0000001922 [system] INFO: ARM_WLAN_WD 2
0000001922 [hal.wlan] INFO: Bringing WiFi interface up with DHCP
0000002974 [system] INFO: CLR_WLAN_WD 1, DHCP success
0000002975 [system] INFO: Cloud: connecting
0000002976 [system] INFO: Read Server Address = type:0,domain:,ip: 10.1.0.1, port: 65535
0000005732 [system] INFO: connected to cloud 10.1.0.1:5683
0000005732 [system] INFO: Cloud socket connected
0000005732 [system] INFO: Starting handshake: presense_announce=1
0000005733 [comm.sparkprotocol.handshake] INFO: Started: Receive nonce
0000005740 [comm.sparkprotocol.handshake] INFO: Encrypting handshake nonce
0000005786 [comm.sparkprotocol.handshake] INFO: Sending encrypted nonce
0000005787 [comm.sparkprotocol.handshake] INFO: Receive key
0000005878 [comm.sparkprotocol.handshake] INFO: Setting key
0000006066 [comm.sparkprotocol.handshake] INFO: Sending HELLO message
0000006067 [comm.sparkprotocol.handshake] INFO: Receiving HELLO response
0000006078 [comm.sparkprotocol.handshake] INFO: Completed
0000006078 [system] INFO: Send spark/device/claim/code event
0000006079 [system] INFO: Send spark/hardware/max_binary event
0000006079 [system] INFO: spark/hardware/ota_chunk_size event
0000006079 [system] INFO: Send spark/device/last_reset event
0000006080 [system] INFO: Send subscriptions
0000006080 [comm.sparkprotocol] INFO: Sending TIME request
0000006082 [system] INFO: Cloud connected
0000009583 [comm.sparkprotocol] INFO: Received TIME response: 1502647946
My version of the local cloud installation instructions and AP instructions can be found here: