Basic wiring help required (please!)

Projects General Guidance
1

Hi,

Having only been introduced to arduino and electronics in general yesterday I would greatly appreciate some advice on my circuit.

I am trying to make a thermometer with LEDs lighting to represent the mercury in a traditional thermometer as the temperature falls/ rises.

As I am a total beginner both in electronics and in C code I have so far only been able to get a temperature reading and i've only managed to light the top LED (BRIGHT!) and the one below it (not bright).

if anyone could offer some advice I would greatly appreciate this. The kit I have contains:

Large 830 tie-point Prototype Board with dual power rails on each side
Prototyping Male-Male jumper Wires:
20cm x 4
16cm x 4
12cm x 8
8cm x 49
25 x Resistors:
100R x 5
220R x 5
330R x5
1K x 5
10K x 5
15 x Diffuse 3mm LEDs:
Red x 5
Green x 5
Yellow x 5
General Purpose Diode: 1N4148
Mini push-button switches x 5
Miniature speaker
9V Battery lead to provide power on the move (complete with connector to plug directly into Arduino)
16X2 LCD Module with blue backlight (16-pin header provided to enable direct plugging into breadboard)
10K potentiometer for setting contrast on LCD Module
LM35DZ temperature sensor (including noise reducing capacitor)
2X Light dependent resistor (50K - 2M resistance variation 10 lux to dark)
DHT11 Digital Humidity and Temperature sensor
Tilt switch (non-mercury, switches ON when more than 10 degrees from horizontal)

Thank you.

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2

Based on your picture, you don't have any resisters with your LEDs. You must always use a resister with an LED to limit the current used. Try a 470 ohm 1/4 watt resister. That may or may not be causing to much draw on your Arduino for it to run reliably.

3

Thanks, will I need one resister for each led? I've only got a few of each resister (in my list above)..

4

If there will only be one LED on at a time, you might be able to share a resistor. If they're ever on at the same time, they should each have one.

5

Yeah the idea is that bottom light will be for example: 0 degrees C and the top one will be say 30 degrees C (havent yet decided on the best scale to use) so each LED will be assigned a temperature to come on at and for simplicity I will only have one LED on at once. Where would the resistor go in my circuit?

Also I want to keep the brightness of the LED's the same and something isn't quite right at the moment. I apologise for my lack of knowledge on this subject!

Thank you

6

If you tie all resisters to one common ground with a 470 ohm resister in line then all will have equal brightness.