With more and more embedded systems being connected, sending state information from one machine to another has become more common. However, sending large packets of data around on the network can be bad both for bandwidth consumption and for power usage. Sure, if you are talking between two PCs connected with a gigabit LAN and powered from the wall, just shoot that 100 Kbyte packet across the network 10 times a second. But if you want to be more efficient, you may find this trick useful.
As a thought experiment, I’m going to posit a system that has a database of state information that has 1,000 items in it. It looks like an array of RECORDs:
typedef struct
{
short topic;
int data;
} RECORD;
It doesn’t really matter what the topics and the data are. It doesn’t really matter if your state information looks like this at all, really. This is just an example. Given that it is state information, we are going to make an important assumption, though. Most of the data doesn’t change frequently. What most and frequently mean could be debated, of course. But the idea is that if I’m sending data every half second or whatever, that a large amount isn’t going to change between one send and the next.
Our guest for this week’s Hack Chat will be Limor “Ladyada” Fried, the founder of Adafruit, and someone who needs no introduction but we’re going to do it anyway. Adafruit began as a weird side project selling exact reproductions of the Roland TB-303, building cell phone jammers, and making guides to build your own USB power bank before USB power banks were a thing. This has grown into Adafruit, a company with over 100 employees in the heart of New York City, one of the best places for learning and making electronics, and a place that does everything Open Source with zero loans or VC money. By any objective measure, Adafruit has become the most successful business story to come out of the Maker Movement, however nebulously that can be defined.
