How can I get the value of pin A0 from the second sketch into the JSON array in the first sketch? - json

Question

Can anyone help me figure out how to piece these two pieces of code together so I get the result I need? My eyes are crossing from looking at this. I know this is a breeze for probably everyone other than myself, but I am not a programmer and this is just for one small personal project.
So far, after hours and hours of reading and watching any videos I could find relating to Arduino, Pubnub and sensors, I have sensor reading publishing to Pubnub. I created a Freeboard account for visualization and that's all working. The problem is, the data being published is wrong.
Basically, I'm wanting to read a battery voltage and publish it to PubNub. I can get the Arduino (Uno R3) to read the voltage and I can adjust the values in the code to match the actual voltage. The problem I run into is taking that bit of code that works and stuffing it into the JSON array that gets published to PubNub.
If anyone would be willing to help me and maybe explain a little (or not - I'm okay if I just get it working), I would SO appreciate the time, help and effort.
Thanks!
//Each sketch works indepently. I need to merge them to get the correct reading published.
//VoltagePubNub.ino
(This is the one that publishes, which is what I want. I just want the published value to be the value of the second sketch.)
#include <SPI.h>
#include <Ethernet.h>
#include <PubNub.h>
#include <aJSON.h>
// Some Ethernet shields have a MAC address printed on a sticker on the shield;
// fill in that address here, or choose your own at random:
const static byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
// Memory saving tip: remove myI and dnsI from your sketch if you
// are content to rely on DHCP autoconfiguration.
IPAddress myI(192, 168, 2, 114);
IPAddress dnsI(8, 8, 8, 8);
const static char pubkey[] = "publish_key";
const static char subkey[] = "subscribe_key";
const static char channel[] = "channel_name";
char uuid[] = "UUID";
#define NUM_CHANNELS 1 // How many analog channels do you want to read?
const static uint8_t analog_pins[] = {A0}; // which pins are you reading?
void setup()
{
Serial.begin(9600);
Serial.println("Serial set up");
Ethernet.begin((byte*) mac, myI, dnsI);
Serial.println("Ethernet set up");
delay(1000);
Serial.println("Ethernet set up");
PubNub.begin(pubkey, subkey);
Serial.println("PubNub set up");
delay(5000);
}
void loop()
{
Ethernet.maintain();
EthernetClient *client;
// create JSON objects
aJsonObject *msg, *analogReadings;
msg = aJson.createObject();
aJson.addItemToObject(msg, "analogReadings", analogReadings = aJson.createObject());
// get latest sensor values then add to JSON message
for (int i = 0; i < NUM_CHANNELS; i++) {
String analogChannel = String(analog_pins[i]);
char charBuf[analogChannel.length()+1];
analogChannel.toCharArray(charBuf, analogChannel.length()+1);
int analogValues = analogRead(analog_pins[i]);
aJson.addNumberToObject(analogReadings, charBuf, analogValues);
}
// convert JSON object into char array, then delete JSON object
char *json_String = aJson.print(msg);
aJson.deleteItem(msg);
// publish JSON formatted char array to PubNub
Serial.print("publishing a message: ");
Serial.println(json_String);
client = PubNub.publish(channel, json_String);
if (!client) {
Serial.println("publishing error");
} else
free(json_String);
client->stop();
delay(5000);
}
//VoltageSensor.ino
(This is the one with the correct value, but no publish feature.)
int analogInput = A0;
float vout = 0.0;
float vin = 0.0;
float R1 = 31000.0; //
float R2 = 8700.0; //
int value = 0;
int volt = 0;
void setup(){
pinMode(analogInput, INPUT);
Serial.begin(9600);
Serial.print("DC VOLTMETER");
Serial.println("");
}
void loop(){
// read the value at analog input
value = analogRead(analogInput);
vout = (value * 4.092) / 1024.0;
vin = vout / (R2/(R1+R2));
Serial.print("INPUT V= ");
Serial.println(vin,2);
delay(2000);
}

Answer 1

It may not be the most glamorous or the proper way of doing it, but I got this to do what I need. I edited the first sketch with the following code:
// create JSON objects
aJsonObject *msg, *analogReadings;
msg = aJson.createObject();
aJson.addItemToObject(msg, "analogReadings", analogReadings = aJson.createObject());
// get latest sensor values then add to JSON message
for (int i = 0; i < NUM_CHANNELS; i++) {
float vout = 0.0;
float vin = 0.0;
float R1 = 33060.0; //
float R2 = 7600.0; //
int value = 0;
int volt = 0;
//Serial.print("INPUT V= ");
//Serial.println(vin,2);
String analogChannel = String(analog_pins[i]);
value = analogRead(analog_pins[i]);
vout = (value * 4.092) / 1024.0;
vin = vout / (R2/(R1+R2));
char charBuf[analogChannel.length()+1];
analogChannel.toCharArray(charBuf, analogChannel.length()+1);
float theVoltage = (vin);
int analogValues = analogRead(analog_pins[i]);
aJson.addNumberToObject(analogReadings, charBuf, theVoltage);
}
// convert JSON object into char array, then delete JSON object
char *json_String = aJson.print(msg);
aJson.deleteItem(msg);
Now the value is published to PubNub and is graphed on Freeboard.io at this link .