Now works.

README.md

@@ -1,6 +1,6 @@
 # Overview
 
-Sound level monitoring via USB Benetech GM1356.
+Performs sound level monitoring using a USB Benetech GM1356 sonometer.
 
 Named after [Loud Howard](https://dilbert.com/strip/1995-04-21).
 
@@ -9,10 +9,39 @@ Big thanks to [Maciej Ciemborowicz](https://github.com/ciembor) for his work doc
 # Requirements
  - [hidapi](https://github.com/libusb/hidapi)
  - An OS which recognises the GM1356 as a USB device (ie. not OSX Big Sur).
+ - A GM1356 sonometer (obviously)
 
 # Usage
 
-TBC
+```text
+bash$ ./howard -h
+usage:  howard [OPTIONS] outputmode1 [ outputmode2 ... ]
+
+Reads maximum noise level from a Benestar GM1356 sonometer
+over a given interval, and optionally stores result in an
+influxdb database.
+
+Valid output modes are:
+  short (single line to stdout)
+  long  (multiple lines to stdout)
+  db    (HTTP POST to influxdb, must also provide INFLUXDB OPTIONS - see below)
+
+OPTIONS:
+   -c           Run endlessly (also see -i and -w)
+   -h           Show this usage text then exit.
+   -i secs      Define time over which to get max decibels
+   -t           Test mode - just probe for sononeter then exit
+   -T           Influxdb test mode - just test influxdb connectivity then exit
+   -w secs      Define period to wait between noise level checks
+                insert will just be written to stdout.
+
+INFLUXDB OPTIONS:
+   -d dbname    Define influxdb database name
+   -H hostname  Define influxdb hostname
+   -p password  Define influxdb password
+   -u username  Define influxdb password
+   -y           Actually write to influxdb.  Without this,
+```
 
 # Screenshots
 
@@ -21,3 +50,10 @@ TBC
 # Implementation Notes
 
  - The device seems to 'hang' periodically and cause all subsequent reads to timeout.  To work around this, after two concurrent timeouts I send an `IOCTL_USBDEVFS_RESET`.
+
+ - I don't yet have configuration commands working, so the following need to be manually configured on the physical device:
+  - slow/fast exponential time averaging
+  - MAX mode
+  - dBA vs dBC units
+
+

howard.h

@@ -1,25 +1,115 @@
+// booleans
+#define TRUE    (-1)
+#define FALSE   (0)
+#define BADFD    (-1)
+
+// buffer lengths
+#define BUFLEN 8196
+#define BUFLENSMALL 255
+
+// Benestar sound meter
+#define MIC_VID  "64bd"
+#define MIC_PID  "74e3"
+
+// mic constants
+#define FLAG_DBCMODE  (0b00010000) // use dBc (not dBa)
+#define FLAG_MAXMODE  (0b00100000) // get max db over interval
+// fast = 125ms exp time avg
+// slow = 1000ms exp time avg
+#define FLAG_FASTMODE (0b01000000) 
+// ranges supported by sonometer
+#define FLAG_RANGE_30_130  (0b00000000)
+#define FLAG_RANGE_30_80   (0b00000001)
+#define FLAG_RANGE_50_100  (0b00000010)
+#define FLAG_RANGE_60_110  (0b00000011)
+#define FLAG_RANGE_80_130  (0b00000100)
+
+// ANSI stuff
+#define BOLD "\x1b[1m"
+#define ITALIC "\x1b[3m"
+#define STRIKE "\x1b[9m"
+#define PLAIN "\x1b[0m"
+#define UNDERLINE "\x1b[4m"
+#define RED "\x1b[31m"
+#define MAGENTA "\x1b[35m"
+#define GREEN "\x1b[32m"
+#define YELLOW "\x1b[33m"
+#define BLUE "\x1b[34m"
+#define CYAN "\x1b[36m"
+#define GREY "\x1b[2;37m"
+
+// Output modes
+#define OM_SHORT  (1)  // Print to stdout in one line
+#define OM_LONG   (2)  // Print to stdout over multiple lines
+#define OM_DB     (4)  // Write to influxdb
+
+
+// Control strings
+#define CMD_CAPTURE    (0xb3)   // take a reading
+#define CMD_CONFIGURE  (0x56)   // apply settings
+#define RES_ACK      (0xc4)     // ack for command
+
+// what to do
+enum run_mode { 
+    M_PROBE,   // measure noise level
+    M_TEST,    // just check for sononeter then exit
+    M_TESTDB   // just check influxdb access then exit
+};
+
+// return codes for  read_single_result()
+enum read_status { 
+    E_NOERROR=0,  // all good
+    E_TIMEOUT=-1, // didn't receive all data in time
+    E_BADREAD=-2  // received too much or too little data
+};
+
+
+typedef struct {
+    int dirty;
+    time_t unixtime;
+    uint8_t flags;
+    double decibels;
+    int rangeidx;
+    char range[BUFLENSMALL];
+    char dbunits[BUFLENSMALL];
+    char checkmode[BUFLENSMALL];
+    char timenice[BUFLENSMALL];
+} result_t;
 enum influxcmdtype { I_READ, I_WRITE, I_PING };
 
-char *getdevpath(int vid, int pid, char *retvar);
-int resetusb(char *path);
+
+// prototypes
+int add_output_mode(char *m);
 char *append(char *orig, char *new, int maxlen);
-void colprintf( char *prefix, const char *col, char* format, va_list *args );
-double getdecibels(uint8_t *buf);
 void cleanup(void);
-void handle_signal(int signum);
-void info( char* format, ... );
-void vinfo( char* format, ... );
+void clear_results(result_t *data);
+void colprintf( char *prefix, const char *col, char* format, va_list *args );
+int configure_mic(void);
+struct hostent *dnslookup(char *hname);
 void err( char* format, ... );
-void warn( char* format, ... );
+double extract_decibels(uint8_t *buf);
+void generate_commands(void);
+char *getprocfspath(int vid, int pid, char *retvar);
+void handle_signal(int signum);
 int hextoint(char *hex);
-int readresult(hid_device *dev, uint8_t *retbuf);
-void dooutput(uint8_t *buf);
-int tcpconnect(char *hname, int port);
-int dohttp(char *hname, int port, char *header, char *body, char *retbuf);
-struct hostent *resolve(char *hname);
-int influx_init(char *hname, char *db, char *user, char *pass);
 int influx_cmd(enum influxcmdtype cmdtype, char *cmd, char *retbuf);
+int influx_httppost(char *hname, int port, char *header, char *body, char *retbuf);
+int influx_init(char *hname, char *db, char *user, char *pass);
 int influx_insert(char *cmd, char *retbuf);
-int influx_query(char *cmd, char *retbuf);
 int influx_ping(char *retbuf);
+int influx_query(char *cmd, char *retbuf);
 int influx_write_decibels(double decibels);
+void info( char* format, ... );
+int init_influxdb(void);
+int init_mic(void);
+int mic_docmd(hid_device *dev, uint8_t *cmd, int cmdlen, uint8_t *buf);
+int output_results(result_t *data);
+int parse_results(uint8_t *buf, result_t *data);
+void pr(char *col, char* format, ... );
+enum read_status read_single_result(hid_device *dev, uint8_t *retbuf);
+int resetusb(char *path);
+int tcpconnect(char *hname, int port);
+void usage(void);
+int validateargs(void);
+void vinfo( char* format, ... );
+void warn( char* format, ... );