Questions tagged [ldr]
A light dependent resistor (LDR) is a resistor where the resistance decreases with increasing light intensity.
2
votes
1answer
47 views
555 timer delay circuit + light sensor?
I am quite new to electronics and I would like to combine these 2 circuits together so that during complete darkness on the LDR, the LED would turn on instantly and when light falls on the LDR there ...
-1
votes
0answers
38 views
NE556 timer dark sensor with turn off delay?
I am starting a project for myself. A night light which turns on when no light falls onto the LDR sensor, and turns off after 1 or 2 seconds when light falls back onto it. I must incorporate the NE556 ...
-1
votes
1answer
55 views
LPC1768 - Green LED when LDR sees light, Red LED when LDR is covered
I have been trying to achieve a task I am working on and I believe I am almost there. It successfully changes colors whenever I cover it but when it does, the red LED keeps blinking instead of it ...
1
vote
1answer
48 views
LDR breaks over time what to do?
http://cactus.io/hookups/sensors/light/ldr/hookup-arduino-to-ldr-sensor
I have the following circuit which was running for a long time but at one point something broke and it started producing high ...
1
vote
1answer
69 views
NE555 and LDR circuit diagram
I have modified a schematic for my project with the following image:
Instead of a 20K potentiometer, I use 100K for more precise adjustment.
Do I need to add a disk capacitor of 10nf or 100nf to Pin ...
0
votes
1answer
56 views
How to find the best way to fade in/out?
I have a bunch of these PAR lights below. They work with DMX and have per LED PAR 3 red, 3 green, 3 blue and 3 white LEDs.
I can set the value for the red, green, blue and white lights independently (...
0
votes
1answer
70 views
Voltage divider for ADC
Can anyone tell me why we use a voltage divider circuit with an LDR for an LDR robot?
For example, why can't we directly take the LDR output and feed it to the ADC port in an ATmega controller? Why ...
0
votes
2answers
59 views
Calculating resistor values for a Schmitt Trigger and LDR circuit
I am trying to make a light sensing circuit which has hysteresis.
I want an op-amp (LM358) to output logic 1 (12v) when the light level rises above 250 lux, and output logic 0 (0v) when the light ...
-1
votes
1answer
35 views
Energia/MSP-EXP432 Issue: Analog In Pin removing voltage from Voltage Divider
In the circuit below, I want to measure the voltage going to the ADC (output from the voltage divider consisting of a fixed resistor and photoresistor) using an MSP-EXP432; however, the MSP-EXP432 "...
0
votes
1answer
55 views
MSP-EXP432 “Analog In” pin taking voltage from circuit [duplicate]
I am building a circuit consisting of a voltage divider (with a fixed resistor and a LDR or photoresistor) outputting voltage to an ADC.
I want to measure the voltage going to the ADC using an MSP-...
0
votes
1answer
31 views
The 7-segment LED display is too dark when connect to a auto dimming circuit
I'm using the below circuit to build a auto dimming circuit. I was fine when I only use one 7-segment led, but when I connect more 7-segment led (parallel to L1) the light intensity is very low. How ...
0
votes
2answers
69 views
Device that transmits signal to computer [closed]
How would I be able to send a notification or email/msg of some sort to my computer after an event has taken place from elsewhere. To be more specific, when a tripwire is tripped, (LDR/Laser beam) how ...
8
votes
1answer
2k views
Please help me understand the following light-controlled relay circuit
I used the following circuit to control the outdoor light, and it works as I wanted.
I am trying to understand the circuit and it looks like a comparator circuit,
but I don't understand the use of ...
0
votes
2answers
68 views
Measure laser with photoresistor (LDR)?
I want to make a simple setum, where I can measure the opacity of air. I want to use a simple laserbeam, which I shoot across the room, and on the other side I want to measure how much is blocked/...
1
vote
0answers
98 views
How to identify different LDR photoresistors that have been mixed together?
I purchased a variety pack of LDR photoresistors from eBay which includes GL5506, GL5516, GL5528, GL5537, GL5539.
The problem is that they all came in the same little bag and are visually identical. ...
0
votes
1answer
273 views
How to use multiple LDR to trigger a led? [duplicate]
Whats the best way to use multiple LDRs to power up an LED? Currently I’m using one LDR which turns on an LED when it senses light. But now I want to use three LDRs (at different locations) to trigger ...
1
vote
2answers
74 views
Light-activating a motor [duplicate]
I have an LDR and it reads higher than 17K ohm when the lighting conditions meet my requirements.
I wish to be able to activate a vibrator motor (coin type 3 Volts) when the LDR has a resistance ...
1
vote
1answer
121 views
Arduino and car's 12V switch
I'm trying to control my headlights with my Arduino and a LDR. For this I will use the Arduino as a middle man between the lights switch and the actual lights.
The switch has three positions OFF / ...
2
votes
2answers
255 views
Chicken coop door opener circuit
I'm designing a circuit that will open a chicken coop when the sun comes up. I've attached a bungee cord to the door which opens the door when a pin is released. This pin is released by a car door ...
-1
votes
2answers
158 views
LDR issue interfacing with ADC [closed]
simulate this circuit – Schematic created using CircuitLab
I want to read the voltage values of LDR (0-5V)but my desire range is less ( 1-3V) through ADC of 10-bit,but i am getting Clipped ...
0
votes
1answer
72 views
Understanding the circuit
I am a beginner electronic student and I know this might sound a bit easy for most of you, but I would like to understand the role of the components used in this circuit - it's an LDR-Controlled DC ...
4
votes
4answers
477 views
How does this LDR controlled light work?
Consider:
The circuit here works based on the resistance of the LDR. I don't understand how it exactly works. It's said when the resistance in the LDR is high, current flows through R2 and the base ...
-1
votes
2answers
164 views
Draw a circuit with a voltage divider, two comparator ICs, LDR sensors
I got this last question to practice for my exam and I got stuck. The question is draw a circuit with
a voltage divider circuit,
two Comparator ICs,
LDR(Light Dependent Resistor) sensor
Outputs:
...
0
votes
1answer
284 views
Use of transistor for switching the led
I have been trying a lot to get my circuit work. I want the led to light up when the LDR receives no light and vice versa. I have found that the LDR offers the resistance of approximately 6k ohms when ...
3
votes
2answers
300 views
Can I use a capacitor to power an Arduino for 5 minutes after the power has been cut?
I'm working on a simple setup using an Arduino Nano to automate the switching of my car headlights when it gets dark. I am happy with how to program the Arduino & LDR use and coding, it will be ...
0
votes
1answer
30 views
Photoresistor Night Switch
I have a problem regarding the schematic from the link below.
I made the schematic from this link, at figure 5:http://www.nutsvolts.com/magazine/article/light-sensitive-circuits
The problem is that ...
0
votes
0answers
136 views
Combining Dark Activated Circuit and Time Delay Off using 555 Timer
I'm currently working on a project. My project is a museum laser security system.
In this circuit, if a thief touches a laser, the DAC will be activated because the laser that is hitting the LDR will ...
0
votes
0answers
82 views
How to connect 5 V relay to ACS712?
I want to make automatic on/off of 60 W bulb using relay, LDR sensor in Arduino, and I need to measure current drawn by the bulb using ACS712 (current sensor) simultaneously. I'm able to these two ...
0
votes
1answer
306 views
Light Activated Switch Circuit with delay
In reference to this circuit: Photoresistor snap-on/off switch. If I wanted to add a small delay so that the circuit doesn't immediately turn then and off if the ambient light temporarily dips below ...
-1
votes
1answer
508 views
Can LDR be affected by temperature?
I have an outdoor setup with arduino monitoring light sensitivity to turn on and off some lamps.
https://diyhacking.com/arduino-ldr-sensor/
This started misbehaving couple of weeks ago and I wonder ...
0
votes
1answer
143 views
How to allow current over a certain voltage
I am new on electronics and i was practicing on transistors. I have a working circuit below. The LDR I use allows current and letting LED smoothly based up to amount of darkness. The Voltage after 2.3 ...
0
votes
1answer
276 views
How to make my automatic night light circuit dimming?
I am working on a project named as automatic night light.The idea is simple; LEDs are on when there is dark then LEDs turn off when the circuit detects light.
However I have constructed the circuit I ...
1
vote
1answer
3k views
Light Dependent Resistor Photoresistor LDR: gl5516 vs gl5506
What is the difference between gl5516 and gl5506? (in a SIMPLE way)
1
vote
2answers
79 views
LDR Photoresistive Track
I completely understand the working principle of light dependent resistor. But there is one thing I am bothered about:
Does the LDRs surface has to be equaly illuminated upon all its surface/upon all ...
-2
votes
1answer
628 views
Arduino analog pin doesn't read correctly without connecting to gnd and Vcc of arduino
I'm using an LDR (photoresistor) with arduino and i have the following two cases:
Case 1:
I connect the input of LDR to Vcc of the arduino, The ground of the LDR to the ground of the arduino and the ...
5
votes
3answers
1k views
measuring time between extremely fast laser beam breakage using LDRs
I am conducting a scientific experiment to approximately measure the entering velocity and the leaving velocity of a magnet through an electromagnetic coil.
Beside the coil are two lasers and two ...
0
votes
2answers
170 views
How to replace an LED with a diode and stop LED after timer ends?
So I have been working on this circuit that basically will activate an LED when the lux levels drop low enough. The time that the LED will remain active for is determined by VR4. I'm having two issues ...
0
votes
3answers
80 views
Can I expect SMD components from a same manufacturer to be identical?
I'm working on a project which requires at-least 2,000 ambient light sensors, and instead of using a microcontroler to manage and monitor the whole system I just want to amplify the output of sensors ...
3
votes
1answer
508 views
Help identifying two lead component with glass cover and serpentine trace under it
I ordered an IR pair of components from Amazon and received this which I do not think is an IR emitter or receiver. Does anyone have any ideas to what this component is? I could not find anything by ...
1
vote
2answers
221 views
Photo Resistor to Complete Circuit in Light
I am trying to create a very simple circuit using a CDS photo resistor. The situation is simple, I need a circuit to be connected when its light, disconnected when its dark. The photocell will sit ...
0
votes
1answer
278 views
LDR / photoresistor issue: resistance is constant in different light conditions
I have installation with Controllino mini, it's essentially an ATmega328, and with 6 LDRs and 6 lasers, creating laser rays/barriers.
The system acts as a lasers labyrinth for entertainment purposes, ...
0
votes
2answers
335 views
Dark sensor - need 500mA output
Here is my dark sensor circuit (below). However, my output current is very low. I get a maximum of 150mA to drive my strip LED. But I require atleast 450mA of output current.
I have tried many ...
1
vote
2answers
1k views
Dark sensor using relay
Trying to develop a dark sensor. Have successfully made it but with a major problem. As you can see the circuit here:
When the LDR is covered the LED lights up using the relay NO terminal. However ...
0
votes
0answers
409 views
Reading an LDR array with a Raspberry Pi
I am trying to repurpose a replica GPO 746 using a Raspberry Pi, however the rotary mechanism is rather different to that in an original 746. The circuit has 12 LDRs arranged in an array (3 columns, 4 ...
6
votes
1answer
218 views
Does an LDR age?
I have had a twilight switch lying in my basement for 5 years after it was used in my garden for about 5 years. This week I took it apart to convert it for (solar) use from 230VAC to 12VDC.
What is ...
0
votes
3answers
282 views
LDR working differently than usual
I observed something different in LDR (Light Dependent Resistor) today. I made a "magic" LED circuit such that when lights are off, the LED glows, else when the lights are on, LDR creates resistance ...
-1
votes
3answers
3k views
What's the role of the transistor in this circuit? [closed]
So I have made this circuit for my project. (Instead of that variable resistor, I have used a single 1k ohm resistor)
I know that a transistor can work as a switch and amplifier, but in this circuit, ...
0
votes
1answer
599 views
How to make the LM339 IC source current on its output pins instead of sinking current?
I know that the LM339 Comparator IC has a current sinking output. I made a small night lamp with the help of a LDR and an LM339 comparator IC. It worked properly.
The LDR connected to the inverting ...
5
votes
3answers
1k views
LM339 Comparator IC is not responding to any input
I came into Electronics through Arduino, so pardon me if my knowledge about non-Arduino circuits is somewhat silly. I am preparing a small electronics project for my school with LDRs to detect light ...
0
votes
3answers
324 views
Light Sensitive One Pulse Activated Switch
Hello I planned a light sensitive one pulse activated switch to know when water tank is completely filled and to turn the water pump off using a relay until I reset the circuit using its N/C Switch.
...
