From c72ea2af416dbaa19cede38099b866f5fcfd910d Mon Sep 17 00:00:00 2001
From: Pim van Pelt <pim@ipng.nl>
Date: Mon, 12 Feb 2018 18:25:36 +0100
Subject: [PATCH] Keep a list of DHT sensors

s_dht is a list of MAX_DHT elements. Pass the index to the callback
so we can report on individual sensors by 0-based index.

Mon Feb 12 18:26:12 2018 - esp8266_052EE8/stat/dht {"idx":0, "temp":18.80, "humidity":31.6}
Mon Feb 12 18:26:12 2018 - esp8266_052EE8/stat/dht {"idx":1, "temp":18.70, "humidity":36.4}
Mon Feb 12 18:26:12 2018 - esp8266_052EE8/stat/dht {"idx":2, "temp":18.80, "humidity":39.5}
---
 src/dht.c | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/dht.c b/src/dht.c
index 945d94e..46dc6d7 100644
--- a/src/dht.c
+++ b/src/dht.c
@@ -4,31 +4,47 @@
 #include "main.h"
 #include "mgos_dht.h"
 #include "mqtt.h"
+
+#define MAX_DHT 8
+
+static struct mgos_dht *s_dht[MAX_DHT];
+static int s_num_dht = 0;
+
 static void dht_cb(void *ud) {
-  struct mgos_dht *dht = (struct mgos_dht *)ud;
+  int dht_idx = (int)ud;
   float t, h;
 
-  if (!dht) {
+  if (!s_dht[dht_idx]) {
     LOG(LL_ERROR, ("No DHT handle to work with!"));
     return;
   }
-  t = mgos_dht_get_temp(dht);
-  h = mgos_dht_get_humidity(dht);
+  t = mgos_dht_get_temp(s_dht[dht_idx]);
+  h = mgos_dht_get_humidity(s_dht[dht_idx]);
 
-  mqtt_publish_stat("dht", "{temp=%.2f, humidity=%.1f}", t, h);
+  mqtt_publish_stat("dht", "{idx:%d, temp:%.2f, humidity:%.1f}", dht_idx, t, h);
 }
 
-static void dht_create(int pin, enum dht_type type) {
+static bool dht_create(int pin, enum dht_type type) {
   struct mgos_dht *dht;
+  if (s_num_dht == MAX_DHT) {
+    LOG(LL_ERROR, ("No more sensor slots available (%d added)", MAX_DHT));
+    return false;
+  }
+
   dht=mgos_dht_create(pin, type);
   if (!dht) {
     LOG(LL_ERROR, ("Could not create DHT sensor on pin %d", pin));
-    return;
+    return false;
   }
-  mgos_set_timer(5000, true, dht_cb, (void*)dht);
+  s_dht[s_num_dht] = dht;
+  mgos_set_timer(5000, true, dht_cb, (void *)s_num_dht);
+  s_num_dht++;
+
+  return true;
 }
 
 void dht_init() {
+  memset(s_dht, 0, sizeof (struct mgos_dht *) * MAX_DHT);
   dht_create(5, AM2302);
   mgos_msleep(250);
   dht_create(4, AM2302);