'Weather Station' desoldered, thought it was broken,ID parts

Development Boards Arduino
1

The LCD was probably just a little out of place, and lost connection, but I think I pretty much killed the ‘motherboard’ while I soldered out these parts.

cfAODl.jpg605×640 53.2 KB
http://i.imgur.com/cfAODl.jpg

As you see, I’ve numbered the stuff I took out.

#1 Resistor? It is marked ‘104’

#2 Oscillator?

#3 Looks like a humidity sensor

#4 Was mounted close to #3, may be a temperature sensor ?

There was also a buzzer on it. (It’s an alarm clock too)

Nothing else had any labelling on them. Has anyone here ever taken apart one of these and used the sensors with Arduino ?

ANSWERS SO FAR:

  1. Identified. Ceramic capacitor, code 104. For anyone else new to electronics and wondering what a capacitor could do in an Arduino project, check this thread http://arduino.cc/forum/index.php/topic,5407.0.html.

  2. Identified. Oscillator, most likely 32.768kHz. I have one that are almost identical, but marked higher frequency.

  3. Tested. I’m pretty sure it’s a humidity sensor. I already have a dew point sensor, going to see if they can’t be combined to do some weather prediction.

  4. Probably temperature sensor, will test later today. I already have one, so it’ll be interesting to see how they compare.

2

#1 Simple ceramic cap. 10E4 pF

#2 Oscillator. Likely at 32.768 kHz for a real time clock

#3 Interesting. If it were flexible, I would claim a piezo flex sensor. If it was exposed to the elements, it might be a rain sensor. Somehow I do not think it was a humidity sensor, but I could be wrong.

#4 Could be anything including a simple capacitor to a temp sensor to a time warp tachyon inversion coil. Does it have any markings? Does it conduct current in either or both directions? If you hit it with a hammer do you go back in time?

3

fll-freak:
#4 Could be anything including a simple capacitor to a temp sensor to a time warp tachyon inversion coil. Does it have any markings? Does it conduct current in either or both directions? If you hit it with a hammer do you go back in time?

I hit it with a hammer and suddenly everything is black and white and everybody are talking about a guy named Adolf… i don’t get it, the tachyon inversion coil had a negative charge field and i had redirected everything from decks 7, 10 and 8.

When they invent electricity here, i will report what happens to that flex sensor when current is passed trough it.

4

(its probably not a flex sensor since all of this was inside the box, its either a rain or humidity type thing)

5

KirkHamster:
#3 Looks like a humidity sensor

#4 Was mounted close to #3, may be a temperature sensor ?

I'd say you're right on both counts - I've seen humidity and temp sensors that looked like that, and this is a weather station after all....
6

The white one, #3 gives these results: with one second intervals

Testing sensor for like 10 minutes.

Hooked it up the same way you would a photosensor.

5V->sensor->analog->10k->GND

0             // starting here
27
68
51
25
51
27
118
141
...           
164       // it stabilizes at around 140-180, weather here right now is temperatures around 0 to -10 celcuis winter, dry, clear air. (norway)
159
198
...
374      // here i do the kind of warm, wet breath on the sensor you would use to clean your glasses
406      // jumps right up to 300-400 then declines pretty quick
361      //
329      // see?
305
269
290
249
236
230
243      // i keep blowing at it with the dry kind of breath you would use to blow dust away
226      // that keeps it from declining further
201      // that keeps it around the 200s
196
211
192
185      // letting it decline, it stabilizes at the initial level
...
219     // here, i am waving my hands slowly to move as much air around as possible. (trying to change air pressure)
249     // that keeps it in the 200s too, but somewhat higher..
270
307
265
237
262
...

Still somewhat unsure how to proceed.

But hey, OP delivar !

7

I remapped the sensor values from 0-1023 to 0-99 to get a humidity percentage, seems to flat out at around 5% then, which would be very low… when this box was a “Weather Station” it would give the humidity in that room to around 25%. (just remembered that it actually displayed the humidity %, but it also displayed the current/upcoming weather in “weather tv icon” style, with LCD pictures of clouds, rain and suns)

8

KirkHamster:
I remapped the sensor values from 0-1023 to 0-99 to get a humidity percentage, seems to flat out at around 5% then…

Relative humidity is a function of temp and pressure. You need to correct the reading for the current temp to determine the RH. You can ignore pressure, for the most part.

9

WethaGuy:
Relative humidity is a function of temp and pressure. You need to correct the reading for the current temp to determine the RH. You can ignore pressure, for the most part.

Interesting, WethaGuy :smiley:

I read myself up on wiki: http://en.wikipedia.org/wiki/Relative_humidity and found a formula:

Ew* = (1.0007 + 3.46 * 10^-6P) * (6.1121) * e^((17.502T)/240.97+T)

Where

e = the natural number or the sensor value ? because if it is the natural number, the sensor reading disappears in this formula… ?

P = pressure

T = temperature

Ew* = relative humidity

Ignoring air pressure would reduce this to: (i think, my math skills are not so good anymore lol)

Ew* = 1.0007 * 6.1121 * e^((17.502*T)/240.97+T)

which would be pretty straightforward to calculate !

I’ll try this later, and report back :smiley:

Unless someone has something to add regarding the formula…

10

Using an assumed temperature for 20C, it gives the result 41.09 assuming e is the sensor value remapped.

This would not be far off the truth I think, though a bit high.

I would very much think e is the natural number in such a formula, this being a logarithmic type of conversion is seems ?

/unsure

Maybe 5V is too much for this sensor ? It was driven off 2xAAA.

Edit: i think i did multiplication instead of pow, so this value could be very very wrong, bit still not so untrue hehe…

Edit2: found some code i’m going to mod a little bit, this could work! http://www.instructables.com/id/Arduino … /?ALLSTEPS

tempc = tempc/8.0; 
tempf = (tempc * 9)/ 5 + 32;

valb = analogRead(putPin); // humidity calculation
prehum = (valb/5);
humconst = (0.16/0.0062);
humi = prehum - humconst;
pretruehumconst = 0.00216*tempc;
pretruehum = 1.0546-pretruehumconst;
truehum = humi/pretruehum ;
delay(1000);

Serial.print(tempc,DEC);
Serial.print(" Celsius, ");
Serial.print ("Humidity: ");
Serial.print ((long)truehum);
Serial.println ("% ");

tempc = 0;
11

According to http://en.wikipedia.org/wiki/Arden_Buck_equation the e in the above equation is the base of the natural logarithm (2.71828)

12

n1ist:
According to http://en.wikipedia.org/wiki/Arden_Buck_equation the e in the above equation is the base of the natural logarithm (2.71828)

Thats what I would have thought. I need to research that more. Right now I think I have to rewire my project, something must have gone wrong when moving it from an Uno to a Mega :slight_smile: Got some flux hehe. Also have been working on getting a rover up and running.

I also have some more stuff lying around just waiting to be scavenged :slight_smile: I’ll post pack when I fix the sensor parts.