For the IR_FLAME_SENSOR_analog node, Joshua's code displays the read flame value at the time of periodic sending (once a minute).
For the IR_FLAME_SENSOR_digital node, I programmed a periodic send plus sending every time the flame value changed so we could receive a prompt warning.
From here, download the latest choose_nodes sketch & follow the basic customization in that thread. That node sketch now includes an IR_FLAME_SENSOR_digital option which will immediately send a change of flame status. Near the sketch's end, see version updates & credits. See the links in this post for documentation on several kinds of nodes you can program with this sketch.
This sketch ^^ was updated March 18, 2019: For one thing, as before when a new flame is sensed, that is flagged & sent immediately. However, now the flame flag is not cleared & sent until no flame has been detected for 60,000 milliseconds (a minute).
In addition to the above basic customization ...
// #define IR_FLAME_SENSOR_digital << UNcomment this line (delete //)
#define NODEID 05 << change 05 to a unique number in your RFM69 network
(For this node, I suggest you use NODEID 42 as I will below.)
By this time, you should have at least an RFM69 Gateway (see this post above) & an IR Flame Node 42 programmed for NetworkOne.
When the Gateway is local network-connected & running, the node was programmed with DEBUG, the node is USB-connected to the Arduino IDE computer, & the Arduino IDE Serial Monitor is opened: you should immediately & then at least every 60 seconds see four device values:
1) device 02 (Radio Signal Strength),
2) dev 04 (node voltage),
3) dev 09 (how many times the node tried to resend data before the gateway acknowledged receiving),
4) dev 42 (flame value: 1= no flame, 0= flame).
In addition on the Serial Monitor, immediately when dev 42 (flame value) changes to zero, you should see "FLAME detected" [dev 42 = 0]. Update, March 18, 2019: The lack of flame does not register until dev 42 has a value of one for at least 1 minute & then you will see "No Flame detected for 60 secs." This will help make sure that the possibility of a flame is not cleared too soon. Later when we have a servo sweep the sensor's field of vision, this will preserve a flame detection even when the servo moves the sensor away from the position of detection.