This is just the start, a complement to the Sparrow firmware I'm working on.
To build a program as an example of a device ( ESP32 ) connected to a Sparrow that interfaces with sensors and runs inference on a higher-power processor.
The Sparrow attached to the serial interface here will poll the ESP32 for what it knows and relay upstream
I'm starting with implementing two inbound messages, "poll" and "init" with the idea of using the Sparrow's note templates to match the data coming from the ESP32 by sensor attached. We'll build a bit more code to reduce the individual message cost.
We need to plan out what data we'll send and build a note prototype against the datatype definitions below:
// C macro to convert a number to a string for use below
#define _tstring(x) #x
// Hard-wired constants used to specify field types when creating note templates
#define TBOOL true // bool
#define TINT8 11 // 1-byte signed integer
#define TINT16 12 // 2-byte signed integer
#define TINT24 13 // 3-byte signed integer
#define TINT32 14 // 4-byte signed integer
#define TINT64 18 // 8-byte signed integer (note-c support depends upon platform)
#define TUINT8 21 // 1-byte unsigned integer (requires notecard firmware >= build 14444)
#define TUINT16 22 // 2-byte unsigned integer (requires notecard firmware >= build 14444)
#define TUINT24 23 // 3-byte unsigned integer (requires notecard firmware >= build 14444)
#define TUINT32 24 // 4-byte unsigned integer (requires notecard firmware >= build 14444)
#define TFLOAT16 12.1 // 2-byte IEEE 754 floating point
#define TFLOAT32 14.1 // 4-byte IEEE 754 floating point (a.k.a. "float")
#define TFLOAT64 18.1 // 8-byte IEEE 754 floating point (a.k.a. "double")
#define TSTRING(N) _tstring(N) // UTF-8 text of N bytes maximum (fixed-length reserved buffer)
#define TSTRINGV _tstring(0) // variable-length stringSo for a n-array of DS18B20 temperature sensors with inference response for each, and host information, we might arrive at something like this:
{[("rom": "TSTRING(18)"), ("temperature": "TFLOAT32"), ("inference": "TSTRINGV")} {[("platform": "TSTRINGV"), ("battery": "TFLOAT32"), ("version": "TFLOAT16")]}
This would be the response to the "init" message
The response to "poll" would walk each sensor and pack a json object in the fashion above but with the data populated.
A small bit of message data per polling cycle could be saved by sending the sensor ROM identifiers and creating a template per sensor instead of per sensor type, but we'll see what we get with this.