Sunday, November 15, 2015

Weather station with Arduino, DTH11 and MPL3115A2 Barometric pressure sensor

Nothing special here, I had the sensors laying around and a spare box and Arduino nano module so I just "glued" everything together. In the future I will proably put some remote sensors...if I have time and patience for it.

The finished product (with printed paper graphics glued on the plastic panel):

..This type of LCD is not the greatest of all, just used it because bought two out of curiosity, next time will stick with a classic one.

The internals:

..nothing special, there's a small hole near the humidity detector (blue module near the back panel) for faster response to temperature change.

View from the back, power is by USB directly on the Arduino nano module. The back of the Nokia LCD is visible on the back of the front panel:

Part of the code, just for future reference:
// Nokia 5110 libs
// alti/pressure sensor

 // DHT11 sensor
#define DHTPIN A1     // pin analog 1
#define DHTTYPE DHT11   // DHT 11

const int SENSORADDRESS = 0x60;

Adafruit_PCD8544 display = Adafruit_PCD8544(8, 9, 10, 11, 12); // arduino
Adafruit_MPL3115A2 baro = Adafruit_MPL3115A2();

  // readh dht11 variables
  float hum = dht.readHumidity();
  // Read temperature as Celsius
  float temp = dht.readTemperature();
  // read addfruit variables
  float pascals = baro.getPressure();
  float mb = pascals/100;
  // clear last data on display and display new data
  //display.print("--- Sensor ---");
  display.print("Humi. "); display.print(hum); display.println(" %");
  display.print("Temp. "); display.print(temp); display.println(" C"); // dth not so accurate
  display.print("mB. "); display.println(mb);

Have a nice week!

Monday, November 09, 2015

Airband receiver kit + Si5351

Got one airband receiver kit from a popular an auction site,

(kit's are cheaper now from what I've seen)

Kit includes everything and even some extra components (better more than less).
It worked first time after assembly. Already with that in mind (or as standalone in case of failure) decided to convert it to use the Si5351 clock generator IC, re-using the airband VFO box I made to convert the PAE receiver from single channel to VFO. The Park Air Electronics receiver conversion wasn't successful because of the low range of the internal VFO without manually retuning the coil so the box and the inner Arduino was kind of redundant:

The PAE airband receiver, single channel selection by dip switch's. for what the air band vfo box project was initial intended:
The airband VFO box was supposed to remotely change the DIP switch settings of the PLL, it worked as I programmed but the VFO tuning range was short so I only got 2Mhz excursion from the main frequency before the PLL unlocking... it was kid of bitter taste of a failure in the middle of a success.

So for the Airband kit I place the Si5351 (and the kit itself) inside the airband vfo box and changed the code from the DIP connections to the clock programming of the Si5351. The connection to the airband receiver kit mixer from the Si5351 is strait forward and worked first time:

For the in place kit connection on the PCB what needs to be changed is the connection to NE602 on pin 6 and pin 7, applying the VFO signal on pin 6 of the NE602, the oscillator part (in the kit) is removed by means of disconnecting pin 6 and 7 to the main board..

..using a simple adapter to be inserted inline without modifications on the PCB :

you see the two "missing" pins on the underside that will no connect pin 6 and 7 of the NE602 to the kit PCB
They are never the less connected on the top part of the adapter board and connected then to the VFO (si5351)

The kit without adapter

Final product with adapter in place and connected to the Si5351:
From left to right, back panel, airband kit, arduino and the si5351 module on top, and on the right the from panel with the LCD display and frequency selection buttons.

Still no external squelch and volume on the box (mid and right pot's) because I don't have a drill around....

The power will be provided from the Park Air electronics receiver, that will remain single channel, so when I power it on will get that channel and another one I can select on the new airband kit.

Here's the schematic for the push buttons by popular request:
I had some email requests for the code, placing here a small example for testing single frequency (change for the interest frequency for the Si5351 to generate)

Have a nice week!

Sunday, November 01, 2015

Most import project so far - Night Light

....Yes, if you show LED's to a 5 year old they will never let you go... and if you show that they light up when connected to a will spend the rest of the day watching batteries getting drained.... If besides all this you have a spare project box in hand the litle ones will find a way of re purposing it!
That's what happened when I showed LED's (she discovered then in fact) to my little child, after playing a bit with the LED's she asked me for a night light, she never had one but she knewed what it was... here's the result:

Her design for the LED placement:

And switching bettwen the J of Joana:

And the heart:

Inside looks:

 ... she was also fun of the breadboard....and yellow wires!

I suggested blinking and doing circles using an Arduino but no, it was OK like Arduino was spared!

Have a nice week!

P.S. Now I have to connect to an external supply as requested/ordered!...