verdeimpacat

Most recent activity

• Old: Write up your project and get a Free Espruino! [2019]

  in News • 5 years, 9 months

  

  Nice! Thanks! My mind is into it allready!

• Porting to other STM chips

  in Porting to new Devices • 5 years, 11 months

  

  @Gordon:
  What about upgading the design of Espruino WiFi board to move to more resources rich chip like STM32F413?
  It's such a pitty that the new versions of Espruino drop functionalities just because of the memory limitations...

• Espruino 1v96 is here

  in News • 6 years, 11 months

  

  Great! Very interesting improvements! Wish you great success with the Pixl.js!

• EspruinoWiFi module builtin?

  in JavaScript • 6 years, 11 months

  

  I trust it is not built-in. You will need to have in the initialization part of your code a line like:

  wifi = require("EspruinoWiFi");
  

• Multiple sessions of web IDE

  in Projects • 7 years, 2 months

  

  In my humble opinion, given the stake of IoT applications today, it will help a lot to have easily available open WebIDEs to multiple Espruino instances. It will ease build and debugging of projects with multiple Espruinos and Pucks.

• Temperature regulator

  @verdeimpacat started

  • 15 comments
  • 7,136 views

  @Gordon replied
• Temperature regulator

  in Projects • 8 years, 1 month

  

  Updated code after extensive testing:

  var triac;
  var htu;
  var temp;
  var averageTemp;
  var humidity;
  var compHumidity;
  var targetTemp;
  var tempHistory = Float32Array(60); 
  function onInit () {
     I2C2.setup( {scl: B10, sda: B3, bitrate: 19200 } );
     htu = require('HTU21D').connect( I2C2 );
     // Before anything else we should turn off the triac
     triac=A8;
     digitalWrite(triac,0); //this shoud reset the pin and set it as output
     temp = (htu.readTemperature()+htu.readTemperature()+htu.readTemperature())/3;
     //at power-on we assume the temperature was constant for the entire measurement history
     tempHistory.fill(temp);
     averageTemp = temp;
     //turn HTU21D heater on for two seconds just to make sure the HTU21D sensor
     //has no condensation
     htu.setHeaterOn( true );
     setTimeout('htu.setHeaterOn(false);', 2000);
     targetTemp = 8.00;
  }
         
  function pidControlLoop() {
     temp = (htu.readTemperature()+htu.readTemperature()+htu.readTemperature())/3;
     humidity = htu.readHumidity();
     compHumdity = htu.getCompensatedHumidity( humidity, temp );
     var regulatedTemp = targetTemp;
     //we want to check that moving towards regulated temp does not produce 
     //condensation. Furthermore, if the current temp is close or bellow
     //dew point we wish to move to slightly higher temp
     var dewPointTemp=htu.getDewPoint(temp,compHumdity);
     if (((targetTemp-dewPointTemp) < 1) || ((temp - dewPointTemp) < 1)) {
        regulatedTemp=dewPointTemp + 1;
     }
     //same, we want to check that the oldest temperature measured was above the dew point temperature
     //this is needed to avoid condensation due to thermal inertia for glass or metal objects
     //we better move slowly to higher temperature if such.
     if ((tempHistory[59] - dewPointTemp) < 1) {
        regulatedTemp = tempHistory[59] + 1;
     }
     // here we apply the proportional-integrative-derivative control 
     var PIDresult =0.75 * (regulatedTemp-temp + 2 * (regulatedTemp-averageTemp) + 2 * (tempHistory[0]-temp));
     calculatedPWM  = E.clip (PIDresult, 0, 1);
     analogWrite(triac, calculatedPWM, { freq : 0.2 });
     //Prepare for the next loop
     averageTemp = averageTemp - (tempHistory[59] - temp)/60;
     for (i=59;i>0;i--) {
        tempHistory[i] = tempHistory[i-1];
     }
     tempHistory[0] = temp;
  }
  //power on initialization. Will be deleted if code saved in flash
  onInit();
  // hereby we set the control loop to 60 seconds
  setInterval('pidControlLoop()',60000);
  

  And few thoughts after the prototype build:

  • It is wiser to use a snuberless triac. It's even chipper and allows you to build the power control circuit without R4 and C1. That's good because you will want to keep the ac circuitry as simple as possible;
    
  • The triac needs a 6 cm x 4cm radiator. I trust the triac will not dissipate more than 10-15W, and due to the fact that it is triggered with the MOC3083 zero cross circuit, the heat is kept to a minimum. But since it is powered directly to the ac mains circuitry it's good to avoid any overheating, plastic melting or even worse - fire. After all the load is over 10A at 220V ac;
    
    

  The regulation precision is 0,15°C with the suited PID parameters but may easily move to +/- 1°C when the PID parameters are not adequate.

  No humans, animals or Espruino pico boards were hurt during this experiment, do not attempt to build this project if you are not familiar working with mains electricity and power electronics.

• Is I2S supported in any way?

  in General • 8 years, 11 months

  

  That's fair enough! As a matter of fact I was afraid that one would need to write the code in Assambler language to keep code delay to minimum. And it's fine that there is no hardware lock due to use in whatever board functionality of conflicting resources.
  As for the speed in accessing data: there are plenty of applications like digital to analog audio conversion, bluetooth audio and possibly others where you won't need to store the data ( at least this is my assumption today ) but just to process it on the fly.

• Is I2S supported in any way?

  @verdeimpacat started

  • 3 comments
  • 2,912 views

  @verdeimpacat replied
• Is I2S supported in any way?

  in General • 8 years, 11 months

  

  Hi Gordon,
  What are your thoughts about supporting I2S for audio digital on Espruino? I notice that the ST processor has such interfaces & features and I trust that nice application scenarios may arise from these (like enabling sound output, bluetooth audio, a.s.o.).
  No particular project in my mind, just wondering if there are any hardware/software limitations for use.