"Jim Thompson" <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> a �crit dans le message de news: am7s52h1n9raop40uf1amjje0738513mvs@4ax.com...> On Sun, 07 May 2006 09:19:49 -0700, John Larkin > <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: > >>On Sun, 7 May 2006 01:30:42 +0200, "BrunoG" >><please_reply_in_the_forums@www.micro-examples.com> wrote: >> >>>Hi, >>> >>>Here is an idea about using a LED as a light sensor, to dim a 7-segments >>>LED >>>display : >>> >>>http://www.micro-examples.com/public/microex-navig/doc/096-led-light-sensor.html >>> >>>Questions & comments are welcome ! >>> >>>Thanks, >>> >>>Bruno >>> >> >>Too many excmamation points! >> >>For a more serious challenge, use the live 7-seg display itself as the >>ambient light sensor. No ADC allowed. For advanced credit, no extra >>parts allowed at all, just firmware. >> >>John >> >> > > Are LED's more efficient as light sensors than so called photo diodes? >Hi, Surely not, I just present an odd way to use a common LED. Thanks, Bruno http://www.micro-examples.com/public/microex-navig/doc/096-led-light-sensor.html
using a LED as a light sensor
Started by ●May 6, 2006
Reply by ●May 7, 20062006-05-07
Reply by ●May 7, 20062006-05-07
On Sun, 07 May 2006 07:11:09 -0500, John Fields <jfields@austininstruments.com> wrote:>> in the vessel(FS6 gas filled) > >--- >Fluorine Hexasulfide? Must be some nasty shit... >---I suspect it is SF6: http://en.wikipedia.org/wiki/SF6 Jon
Reply by ●May 7, 20062006-05-07
"Fred Bloggs" <nospam@nospam.com> a �crit dans le message de news: 445E2888.1080608@nospam.com...> > > John Larkin wrote: > >> >> For a more serious challenge, use the live 7-seg display itself as the >> ambient light sensor. No ADC allowed. For advanced credit, no extra >> parts allowed at all, just firmware. >> > > Is that for continuous adjustment or just Lo/Hi operation thresholding? >Hi, in this example this is just an Hi/Lo operation thresholding. for continuous adjustement, an analog extra circuitry would be needed. Thanks, Bruno http://www.micro-examples.com/public/microex-navig/doc/096-led-light-sensor.html
Reply by ●May 7, 20062006-05-07
BrunoG wrote:> "Jim Thompson" <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> a =E9cr=it dans=20> le message de news: am7s52h1n9raop40uf1amjje0738513mvs@4ax.com...>>Are LED's more efficient as light sensors than so called photo diodes?> Hi, >=20 > Surely not, I just present an odd way to use a common LED.Keep in mind that an LED is good at converting to DC, only a range of=20 wavelengths that are shorter than the emitted wavelength. A red LED=20 does not respond much to red light, but produces a fair signals when=20 exposed to green and blue light, etc. Blue LEDs make pretty nice UV=20 detectors that ignore visible light..
Reply by ●May 7, 20062006-05-07
On Sun, 07 May 2006 17:19:03 GMT, Jonathan Kirwan <jkirwan@easystreet.com> wrote:>On Sun, 07 May 2006 07:11:09 -0500, John Fields ><jfields@austininstruments.com> wrote: > >>> in the vessel(FS6 gas filled) >> >>--- >>Fluorine Hexasulfide? Must be some nasty shit... >>--- > >I suspect it is SF6: > http://en.wikipedia.org/wiki/SF6--- Yeah, I know. I was just being a smartass... -- John Fields Professional Circuit Designer
Reply by ●May 7, 20062006-05-07
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> a �crit dans le message de news: 0a7s529c4pfhvnnvr8846e1hrpm58c407k@4ax.com...> On Sun, 7 May 2006 01:30:42 +0200, "BrunoG" > <please_reply_in_the_forums@www.micro-examples.com> wrote: > >>Hi, >> >>Here is an idea about using a LED as a light sensor, to dim a 7-segments >>LED >>display : >> >>http://www.micro-examples.com/public/microex-navig/doc/096-led-light-sensor.html >> >>Questions & comments are welcome ! >> >>Thanks, >> >>Bruno >> > > Too many excmamation points! > > For a more serious challenge, use the live 7-seg display itself as the > ambient light sensor. No ADC allowed. For advanced credit, no extra > parts allowed at all, just firmware. > > John > >Hi, this is an interesting challenge, if someone suggests a working solution, I will link it to my page. Thanks, Bruno http://www.micro-examples.com/public/microex-navig/doc/096-led-light-sensor.html
Reply by ●May 7, 20062006-05-07
BrunoG wrote:> Hi, > > Here is an idea about using a LED as a light sensor, to dim a 7-segments LED > display : > > http://www.micro-examples.com/public/microex-navig/doc/096-led-light-sensor.html > > Questions & comments are welcome !There was a failed project with thermal cameras tracking customers walking through a shop. It failed for various reasons (management mostly) but it used a bunch of LEDs to reset integrators. It was pretty low-res. Thomas
Reply by ●May 7, 20062006-05-07
BrunoG wrote:> Here is an idea about using a LED as a light sensor, to dim a 7-segments > LED display : > > http://www.micro-examples.com/public/microex-navig/doc/096-led-light-sensor.html > > Questions & comments are welcome ! > > Thanks, > > BrunoI believe some microprocessor based smoke detectors use a similar method to initiate a 'test' of the detector (where smoke detectors are installed in hard to reach places). A laser pointing device with a modulated signal is used. The laser is aimed at the smoke alarm LED. The modulated data is received by the LED (and thus microcontroller), and if the data is 'correct', then a smoke detector test is started. Quite a neat solution I think. Jim www.picmodules.com
Reply by ●May 7, 20062006-05-07
On Sun, 7 May 2006 19:20:44 +0200, "BrunoG" <please_reply_in_the_forums@www.micro-examples.com> wrote:> >"Fred Bloggs" <nospam@nospam.com> a �crit dans le message de news: >445E2888.1080608@nospam.com... >> >> >> John Larkin wrote: >> >>> >>> For a more serious challenge, use the live 7-seg display itself as the >>> ambient light sensor. No ADC allowed. For advanced credit, no extra >>> parts allowed at all, just firmware. >>> >> >> Is that for continuous adjustment or just Lo/Hi operation thresholding? >> > >Hi, > >in this example this is just an Hi/Lo operation thresholding. >for continuous adjustement, an analog extra circuitry would be needed.Nope, just a little more firmware. John
Reply by ●May 7, 20062006-05-07
On Sun, 07 May 2006 09:36:02 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:>On Sun, 07 May 2006 09:19:49 -0700, John Larkin ><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: > >>On Sun, 7 May 2006 01:30:42 +0200, "BrunoG" >><please_reply_in_the_forums@www.micro-examples.com> wrote: >> >>>Hi, >>> >>>Here is an idea about using a LED as a light sensor, to dim a 7-segments LED >>>display : >>> >>>http://www.micro-examples.com/public/microex-navig/doc/096-led-light-sensor.html >>> >>>Questions & comments are welcome ! >>> >>>Thanks, >>> >>>Bruno >>> >> >>Too many excmamation points! >> >>For a more serious challenge, use the live 7-seg display itself as the >>ambient light sensor. No ADC allowed. For advanced credit, no extra >>parts allowed at all, just firmware. >> >>John >> >> > >Are LED's more efficient as light sensors than so called photo diodes? > > ...Jim ThompsonThey're pitiful, especially as pv generators, and merely real bad as reverse-biased photodiodes. The active area's tiny, among other things. John
