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September 1, 2010
about 3 years ago
Hello out there,
I'm hoping someone who has this device, or someone from Sparkfun, can provide an answer to a concern that I have:
In the video the host creates a 27-byte message: "Ground Control To Major Tom", when he views the message at "Core" it shows that the message length is 27 bytes and it consumed 2 credits.
My question is: Why does it consume 2 credits? Rock7 says that messages up to 50 bytes are 1 credit.
The only explanation I can come up with is that:
a) There is add'l information sent which adds overhead to whatever your message is pushing you up over 50 bytes (is this overhead variable? fixed?)
b) That transaction performed also includes a check of your "mailbox" which costs an additional 1 credit
Does anyone have any insights into this?
I am looking at using this product to track location and other telemetry data, this would be a one-way situation, no data ever received to the device. My expected message will easily fit into 40-45 bytes, but I'm concerned that a 40-45 byte message will actually consume more data due to some fixed/variable/unknown overhead or being required to check mailbox at each data send which will push me up to 2-3 credits per actual message, doubling or tripling the expected usage cost.
I couldn't find any references to message size vs. data transferred in the developer guide. I also didn't see anything related to the potential for shutting down the checking of the mailbox. I'm hoping someone out there with this product can share some real world experience with the costs and message sizes.
No public wish lists :(