A WIFI Datalogger for Espruino PICO

Posted on Mon 19th, February 2018

• #1

ClearMemory041063
A WIFI Datalogger for Espruino PICO

Github

What it does:
1. Connects to a Wifi router
2. Sends a Dweet containing the local IP address
Dweet
1. Sets the PICO RTC to the time returned by the Dweet Service
2. DIsconnects and reconnects to the Wifi router
3. Serves a Web page that allows the client to enter the filename to assign to downloaded data.
4. Send the collected data in comma separated format CSV with a MIME header that opens an Excel spreadsheet.
5. Collects the data at specified intervals and stores it in ring buffers in RAM.
The Hardware
1. Espruino PICO board running Espruino 1v95 or later software, and an ESP8266 mounted on a shim.
PICO wifi shim
1. A pushbutton switch wired from pin B3 to ground. (Digital Read)
2. A 10k potentiometer or series of 10k resistors wired to vary the Voltage on pin B1 in a range of 0.0 to 3.0 Volts. (Analog Read)
3. (for one program) A DHT22 Relative Humidity and Temperature sensor with the power leads appropriately connected to ground and the 3.3 Volt busses and the output pin with a pullup resistor connected to PICO pin A7.
DHT22

Items to edit in order to run the examples:
1. Local Modules
In the upper right of the WebIDE is a 'gear' looking icon, hover the cursor over the icon and the word settings will appear. Click on the settings icon and then select Project. Use the "Select Directory for the Sandbox " to select or even create a sanbox directory. For example I create a sandbox named EspruinoModules. It has a number of sub-directories. We are interested in the one called \modules.

"C:\Users\jj\Documents\EspruinoModules\modules"

Copy the attached modules files to the folder:

"C:\Users\jj\Documents\EspruinoModules\modules\PICOwifi.js"

and

"C:\Users\jj\Documents\EspruinoModules\modules\ringMod.js"
1. Editing the Programs to run the Demos
"C:\Users\jj\Documents\PICOwifi\logger\Ring\Post19Feb2018\PICOwifi-Dweet-Log-Test.js"

"C:\Users\jj\Documents\PICOwifi\logger\Ring\Post19Feb2018\PICOwifi-Dweet-Log-DHT22.js"

a. ssid - wifi name

b. key - wifi password

c. DweetID make up a name unique to you

d. timezone (-6 is for CST)
```
// things to configure
var ssid="myssid";
var key="mykey";
//set DweetID to a unique value
var DweetID="mydweetname";
// https://dweet.io/get/latest/dweet/for/mydweetname
var verbose; //module is quiet
//var verbose=1; // module console.logs
var timezone=-6;
var dsize=432;//144;
var loginterval=1000;
```
The verbose refers to console output in the PICOwif module.
dsize it the length of the rung buffer used to store data.

loginterval is the number of milliseconds between data samples.

The WebIDE output:
```
 1v95 Copyright 2017 G.Williams
>Start connection process
=undefined
null
IP=  192.168.1.11
null
Mytask 1
Sun Feb 18 2018 20:22:25 GMT-0600
Start connection process
null
IP=  192.168.1.11
null
Mytask 2
dl
rend1
dl
rend1
dl
rend2
rend2
rend2
rend2
rend2
rend2
rend2
rend1
```
The Dweet Page

From a browser enter the IP address
(substitute mysweet name)

https://dweet.io/get/latest/dweet/for/mydweetname

The output displayed on the web page will be
```
{"this":"succeeded","by":"getting","the":"dweets","with":[{"thing":"lovelyDay823","created":"2018-02-19T02:22:25.410Z","content":{"IP":"192.168.1.11"}}]}
```
The Download Page

Using a browser enter the IP address of the PICO

For example:

http://192.168.1.11:8080/
```
To Download data from lovelyDay871 
Name the .CSV file name where you want to save the data 
 Click to download 
```
For now just click. Later try changing the filename before clicking download. Try xxy.csv, xxx , and xx.txt.

For xxx.csv my Windows10 system displays a message at the bottom of the page that says:
```
What do you want to do with xxx.csv?
From 192.168.1.11
Open, Save Cancel
```
The file is opened with Excel.

Example xxx.csv downloaded (see attached file):
```
Station Name	lovelyDay871	 					
Download Time	Sun Feb 18 2018 16:59:12 GMT-0600	 	 	 			
							
N	Date	Temp F	Temp C	Flow l/s	Pump	dhtTemp C	dhtRH %
0	Sun Feb 18 2018 16:55:18 GMT-0600	79.07	25.7	0.67	1	21.6	40.1
1	Sun Feb 18 2018 16:55:19 GMT-0600	79.65	26.35	0.66	1	21.6	40.4
2	Sun Feb 18 2018 16:55:20 GMT-0600	80.02	26.15	0.67	1	21.6	40.2
3	Sun Feb 18 2018 16:55:21 GMT-0600	80.24	27.01	0.67	1	21.6	40.2
```
6 Attachments

• #2

Using the ringMod.js Module

Assuming that the ringMod.js module is located in th emodules folder of the WEBide sandbox.

Require the module in your code and for convience use a variable to specify the length of the rinf buffers.

var R=require('ringMod');
var dsize=432;

Declare an array of pointers to instances of ringMOD and then create the instances

For example:

var data=[];
data.push(new R("Date",dsize,Array,1,1,0,gettime,null,datestring,0));
data.push(new R("Temp F",dsize,Int16Array,100,9/5,32,E.getTemperature,null,tofixed,2));
data.push(new R("Temp C",dsize,Int16Array,100,1,0,E.getTemperature,null));
data.push(new R("Flow l/s",dsize,Int16Array,4096,1,0,analogRead,pinB1,tofixed,2));
data.push(new R("Pump",dsize,Int8Array,1,1,0,digitalRead,pinB3,tofixed,0));
data.push(new R("dhtTemp C",dsize,Int16Array,100,1,0,getTemp,null));
data.push(new R("dhtRH %",dsize,Int16Array,100,1,0,getRH,null));

The fields used when creating instances of ringMOD

ring(hname,size,type,mult,slope,intercept,logfunc,lfargs,format,fargs){

hname - a string that is used for the column title in the final spreadsheet
size - the length of the ring buffer
type - the data type used to store the data. Examples Int16Array, Int8Array etv
mult - multiplies the raw data before storage, divides the stored value before using
slope - the linear regression slope used to scale raw values into engineering units (non-zero) If in doubt use 1.0
intercept - the linear regression intercept used to scale raw values into engineering units (try 0.0)
logfunc - name the function or helper function used to obtain the raw data. Examples:
```
function gettime(a){
return clk.getDate();
}
```
lfargs - any argument needed to complte the logfunc. Example logfunc= "analogRead" and lgargs= B7, if not needed use null

format - name of helper function used to format the data Examples:

function datestring(a){
//  console.log(a);
return Date(a).toString();
}

function tofixed(a,b){
return(a.toFixed(b));
}

fargs - argument used with the format function: For example format =tofixed and fargs=2

Inserting the data

Note the logflag used to suspend logging until the clock etc are ready to log.

function log() {
 var i;
 if(logflag>0){
  for(i=0;i<data.length;i++)data[i].insert();
   digitalWrite(LED1,l=!l);
 }
}

Logging the data

The DHT22 returns data in a callback so call it first and in the callback save the DHT data and do the log()

// Do the logging at loginterval in ms
setInterval(function(){
dht.read(function (a){
 DHTt= a.temp;
 DHTrh= a.rh;
//  console.log("Temp is ",getTemp());
//  console.log("RH is ",getRH());
 log();
});
},loginterval);

The DHT temporary storage variables and the logfunct helper functions

var DHTt,DHTrh;
function getTemp(){return DHTt;}
function getRH(){return DHTrh;}

Creating the CSV data from the data array

The process.memoy() commands fix a bug that the cutting edge version of Espruino has fixed.

Send 10 lines at a time in the drain function to keep from using too much memory at a time.

function onPageRequest(req, res) { 
    var i=0;
    var ii=0;
    var j=0;
    var sss="";
  var a = url.parse(req.url, true);
if (a.pathname.substr(-1)=="/") { // a slash at the end
    res.writeHead(200, {'Content-Type': 'text/html'});
// substitute your own html here
// maybe a button to clear or reset the data log on the Pico
    res.write(page1+DweetID+page2);
process.memory(); 
    res.end();                                
}else{ //filename.csv after the URL slash to do csv files
process.memory(); 
console.log("dl");
    res.writeHead(200, {'Content-Type': 'text/csv'});
//write csv file header
     res.write("Station Name,"+DweetID+"\r");
     res.write("Download Time,"+clk.getDate().toString()+"\r");
     res.write("\r");
//write the column headers for the csv file
  for(j=0;j<data.length;j++)sss+=data[j].hname+",";
  sss=sss.slice(0,sss.length-1)+'\r';
//  console.log("N,",sss);
  res.write("N,"+sss);
  i=0;j=0;
// send the data
  res.on('drain',function(){
process.memory(); /////////////////////////////////////////
    if(j>=data[0].cnt){ //logdata.length){ 
    console.log("rend1");
    res.end();
   }else{
  for(i=j;i<j+10;i++){
    if(i<data[0].cnt){ 
  sss="";
     for(ii=0;ii<data.length;ii++)
      sss=sss+data[ii].getDatum(i)+",";
     sss=sss.slice(0,sss.length-1)+'\r';
     res.write(i.toString()+","+sss);
     }else{
process.memory(); /////////////////////////////////////////
      console.log("rend2");
      if(j){
        res.end();
        j=0;
      }//end if j  
     }
    }//next i
    j+=10;
   }//end else
  });//end on drain
}//end else
 res.on('close', function() {});//console.log("t2close");  });
 req.on('data',function(data){});//,data);});
 req.on('error',function(){});//console.log("reqerr");});
 req.on('close',function(){});//console.log("reqcls");});
}//end onPagerequest

• #3

ClearMemory041063

Using the PICOwifi.js Module

Require and create an instance of PICOwifi

var X=require('PICOwifi');
var Y=new X();

Setup some variables

// things to configure
var ssid="your network name";
var key="your network password";

// used by PICOwifi module
var Startagain=0;
var myinterval;
var verbose; //module is quiet
//var verbose=1; // module console.logs

Create a task or a series of tasks

For example:

var page1 = "<!DOCTYPE html>\r\n<html>\r\n<body>\r\n\r\n<h1>My First Web Page</h1>\r\n<p>My first paragraph.\r\n</body>\</html>";

function mytask(){
 console.log("Mytask");
//// Various user code can go here a simple hello page server
//// is given as an example
var http=require('http').createServer(function (req, res) {
res.writeHead(200);
 console.log("hello");
 res.write(page1);
 res.end();
 res.on('close', function() {});//console.log("t2close");  });
 req.on('data',function(data){});//,data);});
 req.on('error',function(){});//console.log("reqerr");});
 req.on('close',function(){});//console.log("reqcls");});
}).listen(8080); //end server
//// end user code  
}//end my task

Setup function to start the wifi and check it periodically

function test(){
    Y.connect(ssid,key,mytask);
}//end test

myinterval=setInterval(function () {
//  console.log("Test for error");
  if(Startagain){
   Startagain=0;
   test();
  }//end of Startagain
}, 2000);

test();

The Startagain variable can be used in the task code to cause the WIFI to restart. A tasknumber could be used in Mytask to take the tasks through a series of tasks

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A WIFI Datalogger for Espruino PICO