99 Threads found on edaboard.com: Photodiode Switch
Hello, Im looking for help to the following problem:
Im sending timing signals with directed narrow angle IR leds. When IR LED switches on I should detect signal with +5V or +3.3V GPIO pin. Most important is to get constant time, lets say?10ns, between IR present and detection. It wouldnt hurt to get long range (3-4m) too.
Hobby Circuits and Small Projects Problems :: 25.10.2010 01:10 :: joonasreunamo :: Replies: 14 :: Views: 4010
Lasers seem to be the best as IR doesn't work well :oops:
Do i need to modulate the laser in this case ? Or even unmodulated plain laser will do?What about the detector for modulated laser ..any circuit ideas,links available ?
What kind of laser will work in my case?I am planning to use laser pointer as the source.Can i modulate it and build a
Hobby Circuits and Small Projects Problems :: 19.12.2003 17:30 :: nips :: Replies: 15 :: Views: 2246
I dónt think hemon its a good ECG. I did it with a photodiode instead of the orp that appears in the circuit and it does´nt work, it have too noise and you do not detect the pulse you detect small movements of your finger. I think this one work better.
Electronic Elementary Questions :: 23.04.2006 00:05 :: Charlie_Brown :: Replies: 40 :: Views: 26906
Flatulent's comments are quite correct. I would add, you can use transistors to source and sink current within your circuit but the beauty of relays is that they provide isolated contact closure--no references to anything else in your circuit. Two transistors will never exactly behave like a relay.
The primary drawback to the relay is tho
Electronic Elementary Questions :: 04.10.2004 19:19 :: golfbumb :: Replies: 11 :: Views: 3505
i want to know which one is better : photodiode or Phototransistor ? and give me the reason? coz i want to use light senor for my project. it's better if there any some reference about it.
Electronic Elementary Questions :: 28.04.2006 03:10 :: Elits :: Replies: 8 :: Views: 6673
what is sutiable material for covering ir photodiode and ir led used in proximity detector ckt.
for following purpose without affecting operation like range and sensitivity
1> protection from dust and humidty
2> protection from changes in ambient light
3> protection from bright light if it will fall on photodiode it will suprress the ir sign
Hobby Circuits and Small Projects Problems :: 14.07.2006 08:58 :: nikhilele :: Replies: 8 :: Views: 1622
I am trying to compare is it possible to get better results ( noise, BW...) dividing large junction capacitance of photodiode to smaller sections.
I attached an example picture, which shows the idea.
As you can see ( picture ) there has used separate TIAs for all of the smaller photodiodes. I think to reduce power dissipation there could be
Analog IC Design and Layout :: 04.07.2008 13:46 :: Taskuraha :: Replies: 5 :: Views: 440
I have not being a member of edaboard for a long time so please inform me if I can place this post in a better place. I thought that this would be a good place since PIN diode are used a lot in RF applications, although this is not an RF application.
I need a good source of information (Technical or Application notes) on
RF, Microwave, Antennas and Optics :: 16.06.2009 19:35 :: CVT :: Replies: 4 :: Views: 2850
You can find photodiodes with eye similar sensitivity- if it is a aspect for you...
Microcontrollers :: 09.01.2010 08:59 :: karesz :: Replies: 4 :: Views: 883
They aren't the right chips for the job and the LM567 is obsolete anyway.
You just need a light source and photodiode or phototransistor. If there is significant ambient light you will need to modulate the light source at a few kHz and have a filter on the receiver. Another approach is a laser pointer and phototransistor.
Hobby Circuits and Small Projects Problems :: 20.02.2010 09:14 :: keith1200rs :: Replies: 4 :: Views: 3115
Can anyone tell me what should be the optimum values for R1,C1 and range of R3 so as to get the dark current of s5972 photodiode(from Hamamatsu) which is of pico ampere range?The sensitive area of photodiode is properly covered to avoid any kind of reflections so as to get the dark current as
Analog Circuit Design :: 30.08.2011 03:31 :: anushaas :: Replies: 27 :: Views: 1357
as tittle above, how do i do connection for the drive the mos switch by hpcl-3120. like which pin to the Gate of mos and drains, and what should i connect to the anode and cathode pins of the opto driver
If you are intending to drive a nMOS for a high side switch, you may want to try the configuration as attached
Power Electronics :: 14.12.2011 17:09 :: gdylp2004 :: Replies: 4 :: Views: 592
The 1k series resistor help protecting the photodiode for adjusting the 1M variable resistor to a very low value? :wink:
Electronic Elementary Questions :: 07.02.2012 19:32 :: mister_rf :: Replies: 8 :: Views: 606
May I obtain your recommendations on a design suitable to detect a flame 10 meters away?
Our objective is to find an infrared photodiode or phototransistor for a fire-prevention product.
It needs to be able to detect a hot stove element ten meter away (with or without a fire on it),
while at the same time yielding the maximum dynamic
RF, Microwave, Antennas and Optics :: 17.09.2012 23:38 :: xawtor :: Replies: 9 :: Views: 1296
I went back to the circuit and checked that the voltage at the LEDA pin is constant, and it sources a DC 1A regardless of the input level. This is without the switch.
When I add the switch and increase the frequency to 10 kHz or so, the current from the LEDA pin drops, which I am measuring with an ammeter, and the current through the LEDs are most
Analog Circuit Design :: 16.02.2013 19:28 :: kyungmin1125 :: Replies: 7 :: Views: 162
At 10cm and 2kHz, the amplitude was about 3Vpp.
With 100 ohm load resistor as used by the OP, you are in the same order of magnitude. 100 ohm is actualy reasonable with a phototransistor to achieve the intended bandwidth. But a cascode circuit can achieve low phototransistor load impedance and higher output voltage.
Analog Circuit Design :: 09.03.2013 11:31 :: FvM :: Replies: 9 :: Views: 216
If the Tesla coil should spark by audio signal, why not use a simple VOX? This is a Voice-Operated switch, operates wirelessly, and in the audio amplifier after the microphone you can add a filter for a selected tone, so the Tesla coil will not spark at ANY sound but only one you send from your speaker.
You can also use a laser pointer as trans
Hobby Circuits and Small Projects Problems :: 13.06.2013 10:21 :: jiripolivka :: Replies: 4 :: Views: 262
I am using a photodiode SFH206K (datasheet attached with the mail). The laser light is incident on the photodiode with a frequency of 10 and 20 Hz. Can you suggest me proper value of the RC filter given in the circuit attached with the mail. I tried with R7 = 220K and C55 = 100nF but none of the lights are detected and if I neglect the f
Analog IC Design and Layout :: 05.06.2013 14:01 :: nacoolp :: Replies: 1 :: Views: 96
I would like some comments on a photodiode amp I am designing. I would like to make it with several different switchable sensitivities. The basic design is a LTC6241 op amp with the PIN photodiode connected in photovoltaic mode (transimpedance amplifier configuration). The photodiode goes to a virtual ground at the (-) (...)
Analog Circuit Design :: 19.06.2013 20:35 :: Tunelabguy :: Replies: 0 :: Views: 19
I have an optical sensing system that uses three LEDs (LED1, LED2 & LED3) as transmitters. The lights from these LEDs are detected by three photodiodes (PD1, PD2 & PD3). The signals from the PDs are passed through an Analog Circuit that is common to all. Then the analog output is passed through three different digital circuits Dig1, Dig2 & Dig3 for
Professional Hardware and Electronics Design :: 21.11.2001 05:02 :: IndiJones :: Replies: 8 :: Views: 1374
The easiest way to solve this problem is to use a simple interferometer made with a LED and appropriare collimator. Then use a photodiode coupled to an up/down counter to count the interference fringes as the focuser moves.
Professional Hardware and Electronics Design :: 21.05.2002 03:04 :: Rainbow Wizard :: Replies: 16 :: Views: 2306
You must 'linearise' your photodiode, look this document :
And simply use a trigger, or a ADC which you will send data signal.
Hobby Circuits and Small Projects Problems :: 02.02.2005 19:06 :: manu :: Replies: 15 :: Views: 2625
Definition of passive device:
Passive device=energy transformation, electromagnetic energy to another, or reciprocal. Ex: Heat by Joule Effect.
A motor or loudspeaker are another examples of passive device.
Active device=drive energy, the ability to a
Electronic Elementary Questions :: 04.05.2006 18:45 :: teteamigo :: Replies: 11 :: Views: 7024
Use a commercial passive IR detector (as used in burglar alrm systems)
Use an IR photodiode as a detector(plus the necessary amplifier). Place a Fresnell lens in front of the photo diode. The humabn body will be a source of IR signal. Use a high pass filter to detect the target movement (The Fresnell lens will "amplify"target movement.
Electronic Elementary Questions :: 13.01.2005 13:25 :: klystron :: Replies: 3 :: Views: 729
I have designed my own Line Follower Robot, I wrote the program for PIC using PICBasic Pro.
'* Name : Path Finder Robot.BAS *
'* Author : Omar Udai Shacker *
'* Notice : Copy
Microcontrollers :: 07.05.2005 09:31 :: glenjoy :: Replies: 19 :: Views: 1833
A problem about an integrator simulation;
when i simulate an integrator ,a warning is followed that missing bulk source(a reset MOS switch ) would be forwardly biased. i do not know why?
1.a photodiode is connected to negative input terminal of operational amplifer.
2. a 2.5v referrence voltage is connected to positiv
Analog IC Design and Layout :: 02.06.2005 05:26 :: samuel :: Replies: 0 :: Views: 584
Firstly to your 2 circuits:
1. At the transistor's base you need just ≈0.7V to conduct enough current to turn on the LED. In "saturation Uce can go below 0.5V, so you will have ≈2.5V for LED..
2. In this case the Ub voltage, to turn this transistor on, will be Uled+0.7V and that will exeed your 3V battery supply. It is possible that i
Hobby Circuits and Small Projects Problems :: 03.08.2005 04:30 :: IanP :: Replies: 7 :: Views: 1492
When talking about flash we should define what is the flash ? Are we talking about light intensity cycle when it goes from ON to complete dark OFF (human perceived dark)? Or we about less than 100% AM modulation of light?
Usual lamps do not switch off light radiation for a time 1/50 sec, they are inertial. AC modulates the light - when experimenti
Electronic Elementary Questions :: 21.01.2006 16:38 :: artem :: Replies: 24 :: Views: 1660
I need suggection for the circuit with following requirements :
- Circuit should withstand against dark current fluctuations from photodiode and maintain its output .
- low OFF current (no more 5 uA)
- low voltage (2 - 4 V)
- switch ON slew rate max 3 usec
- switch OFF slew rate amx 10 usec
- Temperature range -30 - 75 C
Analog Circuit Design :: 18.02.2006 13:24 :: artem :: Replies: 0 :: Views: 498
Your photodiode is in wronge direction, you must reverse the diode direction.
Hobby Circuits and Small Projects Problems :: 12.05.2006 17:19 :: leotim :: Replies: 7 :: Views: 1624
Excellent idea, and relatively simple.
Scanned LEDs like this are off most of the time. Reverse bias the LED and the leakage current goes up and down with the amount of light, just like a photodiode but the LED isn't made as sensitive as a real photodiode. Still useable..
Notice the whole matrix graph go up when his hand blocks more of the
Microcontrollers :: 17.07.2006 16:05 :: Alan69 :: Replies: 5 :: Views: 2604
How would you solve the problem when you need multiple spi slave devices to your pic ? ( i/O expander, digi pots ,... )
Good question. Well, I'll have a very simple header for SPI, SCLK, SDAT, GND and VCC, and possibly CS. But, for multiple connections to SPI I will obviously need multiple CS lines as you rightly
Microcontrollers :: 24.08.2006 18:58 :: Buriedcode :: Replies: 20 :: Views: 5749
Thank you for your help.
"current mode" means the input for my optical receiver is in current format, for example 10uA as the output nature of the photodiode.
i just learned that PRBS can be generated from a matlab using some scripts, or digital circuits as described above.
I will try to import the PRBS to Cadence, hopefully I can find a
RF, Microwave, Antennas and Optics :: 18.10.2006 04:46 :: dog1357 :: Replies: 2 :: Views: 1733
Why don't you use a photodiode instead.It's worth a try .Anyway your project is fabulous and very exciting
Microcontrollers :: 31.10.2006 07:43 :: ajaykumar988 :: Replies: 2 :: Views: 825
Using a small transformer may help because the windings of the transformer form a filter by their very nature.
However, I do not think you are at the root of the problem yet. You state that the circuit goes "dead". But what exactly does that mean? Is the microcontroller stopped executing code? Or is the IR receiver sending out garbage that
Hobby Circuits and Small Projects Problems :: 25.04.2008 14:40 :: banjo :: Replies: 20 :: Views: 5077
I need to position or ground a mechanical system during construction. I need a sensor to detect a zero mechanical point. Precision home mechanical switches are available but too costly - 3-5 um repetitive accuracy costs more than 100 Euro .
Actually 10 um precision is affordable . I guess the easiest way to build such is to use LVDS .
Robotics and Automatics Forum :: 23.05.2008 14:25 :: artem :: Replies: 6 :: Views: 698
A phototransistor with unconnected base (as in SFH9201) has limited options to recover rapidly from overload. As you already found out, the saturation also occurs without an external voltage during the light pulse.
The only option is to switch a low pullup-resistance temporarily, but it may be still insufficient to achieve an acceptable recover
Analog Circuit Design :: 25.05.2008 18:27 :: FvM :: Replies: 3 :: Views: 811
A remote control receiver isn't well suited to get a defined sensitivity, you have no option to adjust the proximity switch. But for applications, that require maximum sensitivity only, this isn't an issue.
Generally any receiver get's saturated at a certain DC light intensity. I'm not sure, if an remote control receiver can operate with direct
Microcontrollers :: 27.06.2008 15:57 :: FvM :: Replies: 5 :: Views: 2532
I propose a phys. model so:
Almost of comercial IR LED produce IR beam with beam divergence about 10-20 degree. Ignoring all the IR absortions in short distance, IR intensity can be shown as a simple function of the distance.
Let say: L= optial travel path length. I(L)= IR intensity at L.
=> I(L)=k*1/L^2. When k is some constant.
Let L shi
Electronic Elementary Questions :: 19.07.2009 07:20 :: Thanhlongbin :: Replies: 42 :: Views: 12099
Hi... I am new to microcontroller. Recently, I was given a task to use a PIC18F4550 to control a servo motor. How can this be done? I've damaged quite a few of them in my school lab.
I heard for a servo motor, the PWM on time for its centre position is 1.5ms. I am required to activate a laser pointer (at RC0) when it is at its centre position.
Microcontrollers :: 12.08.2009 14:46 :: Innovator :: Replies: 1 :: Views: 3980
1. Light mode;
2. Sound mode.
When SW1 is in Light mode (sound mode is disabled) then with SW2 i can choose:
1'. Light activated trigger;
1''. Dark activated trigger.
with BPW34 photodiode
Analog Circuit Design :: 16.10.2009 14:24 :: gvi70000 :: Replies: 7 :: Views: 1010
I am not sure if the threshold is required; if necessary it will be 3.5V.
Can somebody please help me out? I need an example program to try these things. I've tried searching online, but I can not find any of them during this particular PIC. I'm in a desperate position because I've tried to do this for several weeks, but I still can not do and b
Microcontrollers :: 28.01.2010 04:55 :: fireice_121 :: Replies: 0 :: Views: 1395
I was hoping to find something like the one used by Neatorobotics.
Definitely not a TOF laser system then! While I think you could get a TOF laser system down to <$100 it would take a lot of development and custom ICs (been there, done that). Assuming you don't have a huge budget you will have to be more "creative".
Robotics and Automatics Forum :: 24.02.2010 16:37 :: keith1200rs :: Replies: 24 :: Views: 1883
It is only worthwhile opto-isolating if the micro (PWM source) and high current power supplies are separate. It seems like they are (although I see +5V in your diagram - is that correct or is that really +3.3V?).
You have a drawing error in that you have grounded the end of the 33k - you need to remove the ground short.
One problem with tha
Hobby Circuits and Small Projects Problems :: 12.03.2010 14:53 :: keith1200rs :: Replies: 12 :: Views: 2528
If you use IR diodes as transmitters you have to use IR transistor as a receiver
I'm not aware of a silicon based optical sensor, that is not sensitive to the radiation of IR LEDs (either 880 or 950 nm).
Any standard silicon photodiode or transistor has the maximum sensitivity in this range. Even "IR supressed" photodiodes
Professional Hardware and Electronics Design :: 05.04.2010 23:10 :: FvM :: Replies: 10 :: Views: 4829
In which case the problem is that the amplifier tries to amplify a signal relative to ground. So, if the input voltage is, say, 2V, the output wil try to go to -20V! It cannot go below ground.
In general, I would say it is better to use a photodiode rather than photo-transistor in your application. Even if you try to amplify your signal relati
Analog IC Design and Layout :: 30.03.2010 18:07 :: keith1200rs :: Replies: 28 :: Views: 1172
i'm using the Infrared sensor as the transmitter, and photodiode as the receiver.
Added after 9 minutes:
i will upload the schematic tonight
Added after 1 hours 15 minutes:
Microcontrollers :: 03.04.2010 18:46 :: combat cyber :: Replies: 6 :: Views: 950
If until next week i will find a 3 position switch i will use the "switch gain" variant, else...i will use the one with variable resistors.
Meanwhile i also modified the photodiode sensor, so do you think that it will work?
Analog Circuit Design :: 22.04.2010 21:08 :: gvi70000 :: Replies: 16 :: Views: 1077
hi gud ppl,
i m sorry to take you backward.I got a problem just at the begining,wanna go from designing the probe and i have the 2 led and the photodiode.I would like to use the 555 time as the frequency generator but dont know if i must use one or two for each led and if i m using two how will i sinchronize them to do not go at the sametime as the
Microcontrollers :: 22.04.2012 11:24 :: djomgoue :: Replies: 49 :: Views: 5968
The power is usually set with a feedback loop using a photodiode built in to the laser package. Some laser pointers can be modulated so you could use PWM. Some have external power control, I think. However, if yours has neither of these then you are stuck. You could take it apart and try to control it but you stand a good chance of blowing it u
RF, Microwave, Antennas and Optics :: 29.04.2010 18:43 :: keith1200rs :: Replies: 14 :: Views: 1433