AdafruitIO_Feed Moderators: adafruit_support_bill, adafruit

[ulli_doehler]

Using a lot of Adafruit feeds (AdafruitIO_Feed) requires a lot amount of RAM (especially when feed names are quite long). I tried to use the PROGMEM keyword for that, but as I could read outside this forum, PROGMEM definitions for feed strings are not supported up to now. Would it be possible to change this behaviour in the next update of the library?
Standard definition works:

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AdafruitIO_Feed *T_0 = io.feed("b.t-0");


This defintion throws a compiler error:

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AdafruitIO_Feed *T_0 = io.feed(F("b.t-0"));


This definition results in program crash:

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const char *b_t_0 PROGMEM = "b.t-0";
AdafruitIO_Feed *T_0 = io.feed(b_t_0);


Thanks a lot for your support.

[brubell]

There does exist a small topic format (https://io.adafruit.com/api/docs/mqtt.h ... pic-format) in the Adafruit MQTT API.

Are you using the Adafruit IO Arduino library? How many feeds are you defining?

[ulli_doehler]

The number of feeds had been more than 20. In the beginning I applied quite long names for the feeds.
i.e.:

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"beluga.t-0-switch"
"beluga.t-1-switch"
"beluga.h-0-on"
"beluga.h-1-on"
...


and so on. Which resulted in program crash, due to stack overflow. To solve this problem, I changed all names for the topics into shorter strings, as follows:

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"b.t-0-swi"
"b.t-1-swi"
"b.h-0"
"b.h-0"
...


and so on. This solved my problem for the moment. But it would be nice when longer names could be applied, which would help for better readability of the program code. Therefore it would be nice when the F("name to a topic") macro could be allowed.

[brubell]

Could you file an issue over on https://github.com/adafruit/Adafruit_IO_Arduino/issues requesting that we switch to using short feed names in that library?