Electro Optical Gadgets

© Brooke Clarke 2007

Laser Module 635 nm 5 mw "X" 
Blue Laser Pen
TSL267 IR to Voltage
    Methods of Using a Photo Diode
       Novel Method with high sensitivity
Slot Opto Interrupter 
Printer Encoder Strip
TAOS Light to Frequency Converter
10 Hz IR Avalanche Pulser
IR Photo Transistor Sensor
IR Sensor Ircon DN-DNS30-20C
Light to Audio
LM3909 LED Blinkers
Unihedron Nu-B Light Source
    Solar House Number
    Solar Garden Light 
    Small Solar Panels
Optical System Detector
Aircraft Cockpit UV Instrument Light
    MODEL 9379640
    Grimes AN-3038-1 aka C-5 Ultraviolet Cockpit Light
UV Lamp
Exotech 100BX Radiometer
AN/UAS-4 Infrared Surveillance System
Separate web pages for LEDs, Light sources and Flashlights 


These are just quick and dirty gadgets to have a look at some electro optical idea.  Presented in random order.


Got this on eBay with title: "Military Optics ICO-P terrain observation Serbian army" item# 182751050317, Seller: slavors2014, November 2017.
As this is being written I have no idea what it is. The connector has 5 male pins so probably not a light source that would only need 2 pins.
Might be a TV camera, range finder, or . . . .After seeing that my unit does not have the pot core transformer (Fig 6 from eBay) I now think these are part of a beam breaker system and my current unit is a receiver and the Fig 6 unit is the transmitter.  While there is provision for 3 wires from the photodiode/laser diode this unit only has two wires (Orange & Blue) with the third position empty.  It may be that the laser diode version has the third wire for temperature sensing?

It appears that there are two very different units both of which are marked "ICO-P".  I'm guessing one is a pulsed laser diode and the other is a receiver.  Note the eBay listing shows (Fig 6) a large pot core inside, but the unit I received has no pot core.  The pot core is consistent with a switching mode power supply to drive a laser diode.

26 Nov 2017 I've ordered another unit on the gamble that it will be a transmitter.  Note that both transmitters and receivers have the same "ICO-P" label, maybe to not make it clear to an intruder which is the transmitter and which the receiver, but it would be easy for a sophisticated adversary to tell them apart based on function.
To tell which is which the resistance between pins 1 and 2 may be the key, i.e. the receiver unit will measure 300 Ohms and the transmitter unit will measure something different.

Connector Pin Out

Tentative Function
Tentative Function 2
Power Supply Negative
Power Supply -
300 Ohm resR
C705- (10uF 16V)
Resistor Sense/output
Resistor Sense
300 Ohm resL
C701- (10uF 16V)
Power Supply Positive
C704+ (10uF 16V)
Case/Ground Power Supply +
no conn.


T701, T702 & T703 are in a row with T701 close to the photodiode.  Looks like an amplifier chain.  There's a low loss cap near T703.
T704 (small dia) and T705 are near outer edge of PCB near T701
T704E R712 (560) = C705+ (10uF 16V)
R714L (560)= T705C


Fig 1 Open gun sights for alignment.
It's made to clamp on a 1" pipe and can be adjusted
in azimuth and elevation.
Lens is about 35mm diameter.
Military Optics
                  ICO-P terrain observation Serbian army
Fig 2 Marked:  ICO-P
Military Optics
                  ICO-P terrain observation Serbian army
Fig 3
Military Optics
                  ICO-P terrain observation Serbian army
Fig 4 The rear screws were coated in clear potting.
Note there is a hole passing light from the lens.
The screw that's potted in the center of the cover plate may
be for purging the inside with Nitrogen or other inert gas.
Shining a flashlight from inside, through the hole,
makes a 3" diameter spot at 5' away.
The 300 Ohm resistor seen below is connected between:
701 (Violet, pin -2) and 703 (Green pin 1).
Military Optics
                  ICO-P terrain observation Serbian army
Fig 5 Note lack of pot core transformer
Terminals left to right:
701 Violet pin 2 (resistor sense only)
702: no connection
703 Green pin 1 (Pwr Sup Negative,C705-)
704: Pink pin 3 (C704+)
Case Ground: White pin 4
Resistor is Orange, Black Brown (300 Ohms)
Military Optics
                  ICO-P terrain observation Serbian army
Fig 6 Photo from eBay
Note pot core transformer
Resistor may be Orange Orange Red (3k3 Ohms)
Military Optics
                  ICO-P terrain observation Serbian army

Fig 7 Note pins numbered 1 to 5 clockwise starting at notch.
Terminal numbers printed on PCB 701 to 704 left to right.
Military Optics
                  ICO-P terrain observation Serbian army

Laser Module 635 nm 5 mw "X"

Laser Module
                  with "X" reticle

This is a laser module that projects a "+" image instead of just a spot.  635 nm (red) and 5 mw power level.  Max input is 3.2 V.  It draws 33 ma at 3.0 volts.
                  Optics for laser module

The "X" is produced by the parts shown at the left.  A lens and molded plastic line generator, one half of which has lines at 90 degrees to the lines on the other half.  It needs to be adjusted by screwing in or out to balance the brightness of lines.

                  "X" module Beam w/o Optics

With the optics (lens and line generator removed the beam looks like this.
When 5" away from the paper the beam is 1" x  5".

With the laser off, looking into the hole where the light exits you can see what looks liks the edge of a metal disk partially blocking the exit hole.

This is the light pattern from a raw laser diode.  The emitting geometry is a thin line and at right angles to this the beam spreads the most.
Laser Diode Module
                  Obstruction in Path

You can see the disk that's blocking about half of the exit hole. 

Blue Laser Pen

Runs on two AAA batteries.  405 nm @ 5 mw.
Blue (405 nm)
                  5 mw laser pen Blue (405 nm) 5 mw laser pen

TSL267 IR to Voltage

This is one of the TAOS Light to Voltage ICs.  It takes the current from a photo diode and drives the inverting input (virtual ground) to an op amp which converts the current into an output voltage.  They typically offer different model numbers that have different gains and bandwidths.
22 Jly 2007 - A few minutes using the TSL267 with the Battery Top Power Supply and the Printer Encoder Strip looped back on itself seems to confirm my idea that the slot opto interrupter is not working because the light source is closer to a point source than a collimated source.  With a point source the light falling on the strip not only passes at 90 degrees, it also is at other angles, making it much harder to block the light.  I ran this test in the day time, but room IR background saturates the TSL267 so need to wait till dark to really try it out.

Electro Optical
          Gadget TSL267 & 150 LPI strip22 July 2007 9 pm - Used angle head Flashlight about 4 feet from TSL267 and it's working.
The output voltage goes between 0.67 and 2.63 for a Pk to Pk signal of about 1.9 volts.  The speed I was sliding the encoder strip on itself resulted in a frequency of about 633 Hz. 

So it's important that the light source is collimated and desirable that it has near IR output.
Blurry photo hand held auto time exposure.

Theoretically the wave form should be a triangle with points at the top and bottom and the scope image is close but the top and bottom are rounded so looks like a sine wave.  That may be related to the sampling scope's low one shot bandwidth.

So to use the strip ambient light needs to be blocked and a collimated near IR source used.

The Light to Voltage family of TAOS parts uses a photo diode as a solar cell generating a current proportional to the light input.  By connecting the photo diode output to the virtual ground negative input to an op amp the current gets transformed into an output voltage   The negative feedback circuit consisting of a resistor in parallel with a cap allows trading gain and bandwidth to some extent.  The rise time for these varies from a few to a few hundred microseconds.

Methods of using Photodiodes:

Idea for Much Higher Resolution Incremental Encoder

When you look at two identical Printer Encoder Strips as one is moved over the other the amount of light coming through varies from completely blocked off (if they are well aligned) to 50% of the light on the other side of the strip.  So a linear light intensity sensor set so it's full scale output goes from black to 50% of the light source will have a saw tooth output as the strip is moved.  Two of these sensors with a separation that's some integer of the pitch plus 1/4 pitch (i.e. a quadrature sensor arrangement) would allow not only much finer resolution but also direction of movement detection.

This method would not be good for fast turning motors but would be great for things like telescopes that move slowly.  Note that the light intensity is directly proportional to the effective slit width so the voltage output from the light to voltage converter is a straight line function of the displacement of the two strips.  Only an offset and scale factor correction need to be applied.

Instead of taking the photo diode output as a binary signal, process is through a transimpedance amplifier to get an analog signal.  Use an A/D converter to read how much light is there.  There will be some limit on how many bits can be added by I expect that 8 bits is not out of the question.

For most applications only the final position is important so the photo diode output can be split into two channels.  One channel is for conventional digital counting and direction.  During high slew moves the analog channel may or may not be able to keep up.  So a speed based switch driven from the digital channel can turn off the analog output or for lower cost just ignore the lower significant digits during slews.  This might be a problem when in a GOTO mode, so there should be two speeds used, the first for getting near the target and a slower speed used to creep up on the desired setting.  I think this is how they now work, but would be required to use the higher resolution mode.

The reasonable priced angle encoders now have 500 slots per turn (0.72 deg) and the minimum step size you can get is 1/4 pitch (10.8 min angle).
But this might be changed to  2.5 sec angle using the analog method.

When the number of bits in the D/A converter gets high enough variations in the pitch of the strip or wheel will start to show up.  A way around that is to use the index mark to allow calibration of a complete circle by using an external index head to set the position and build a table in EEPROM.

Slot Opto Interrupter

Sharp GP1A50HR
          Opto SlotThis is a Sharp GP1A50HR (Electronic Gold Mine G15889 or GP44).  It's an IR emitter coupled with a photo transistor detector circuit.  The emitter is about 1.1 volts @ 15 ma and the detector circuit runs on 5 VDC.  Gap is 3 mm and slit is 0.5 mm.
+5 VDC from the Battery Top Power Supply shown below with the TAOS Light to Frequency Converter.  By using solid hookup wire just plug the wire into the socket where the IC was before.

Clock Escape Wheel

The LED wired to the output through a resistor is on (output is +5 w/empty gap) and turns off when the beam is blocked.  By placing the gap over the escapement wheel on a Self Winding Clock Co. clock where the wheel has 60 teeth (i.e. 120 beat, or 1 second period pendulum), the LED turns on and off with a one second period, i.e. it sees each of the 120 moves of the escape wheel.  The response time is in the micro seconds if the resistors are chosen per the data sheet. 

Positioning is touchy when held by hand, but some type of fixture would solve that.

Printer Encoder Strip

Electronic Gold Mine G15602.  A 13" long x 0.237" (330 mm x 6 mm) with alternating clear and dark bars at 150 line pairs per inch (5.9 lp/mm).  The dark lines are 0.157" long ( 4 mm).  There is a slot at each end, both angles at 45 degrees and parallel to each other.  I think this was used on a printer to locate the print head.  The obsolete HP Deskjet 3810/3820 Printer series has manuals with product number C8952A and the encoder strip is marked "C8952A-80005".

At 150 lp/inch one line pair takes up 0.006666" (0.17 mm( which is smaller than the 0.5 mm slit in the above Sharp slot type opto interrupter, but that shouldn't matter since when two strips are in the gap and perfectly aligned but out of phase such the bars one one strip are aligned with the spaces on the other no light should get through.  And this is what happens.  The data sheet for the Sharp sensor mentiones that the sensor slot is vertical, i.e. aligned with the long axis of the gap but I don't think that's much of an issue.

It's impossible to hold a folded encoder strip in your hands and adjust it to be black for more than about 1/4".  The problem comes when the alignment of the two strips is off a little the you get a Moiré pattern (Wiki).  The effect can be calculated (Wiki).  For two strips with the same pitch the big distance on the pattern between dark lines is D = p/a where a is in radians and D and p are in the same units.  So for p = 0.0066666" and a = 1 degree or 0.017453 radians, D= 0.38"
angle deg (radian)
D =
0.029 (1.7 arc min)
0.008727 0.76"
0.017453 0.38"
19.5 deg
0.5 mm
If the angle between the two strips was within 1.7 arc min the whole 13" would appear to be black.
The bottom line is that it's not trivial to make a linear encoder that works.
If the two strips are aligned to within 19 deg across the 0.5 mm wide slit then the brightness will be a function of the linear offset between the two strips which will vary as the phase of the pitch.

I've heard that the commercial linear encoders use two sensors for the "A" phase and two for the "B" phase where the two sensors for the same letter are out of phase so one is dark and the other is light.  Theoretically only one A and one B are needed, but by using complementary sensors it works better.  With the folded strip this would be an "A" only incremental sensor, i.e. no direction information.

TAOS Light to Frequency Converter

TAOS TSL245 Electro
        Optical GadgetThe TAOS TLS245 is an Infrared light to frequency converter that runs from 5 volts.  It's packaged in a 3 lead TO-92 like package made of black plastic that acts an an IR pass filter.  So by combining it with one of my Battery Top Power Supplies you get a portable unit.  The Fluke 87 DMM has the ability to read the frequency of an AC signal so the whole setup is easy to use.
Instead of soldering the wires to the sensor I used three Mil-Max sockets (Mouser 575-067700) this way I can just unplug the TLS245 and plug in the TSL237.

Some readings:
dark space <2
indoors bright sunny day outside, no lights on 20 k
160 k
Quartz Halogen desk lamp on low power 18" away 305 k
573 k
Quartz Halogen desk lamp  on high power 403 k
Outside in direct Sun

So this sensor can not be used for directly measuring sunlight.  Of course it can if the Sun light is attenuated, but then the lower end of the dynamic range is also moved up in brightness.

The TAOS TSL237 is probably the same chip as the TLS245 only in a clear plastic housing so it can sense visible as well as near IR light.  This is a single range (i.e. single photo diode) sensor that's been optimized for low light levels and for flat temperature performance.  It's the heart of the Sky Quality Meter used by astronomers to measure light pollution.  Part of the calibration is to determine the output frequency for a dark input thus allowing the actual output to be scaled.  It may take a few dozen seconds to get enough counts if the sky is really dark.

The Narrow-band low-cost spectral light source is another product by the same company that makes the Sky Quality Meter.  It comes in two models, one with all visible outputs and one with a near IR output.  But they don't say wheather or not the peak magnitudes of each source are matched.  That would allow using it to measure filters or materials.  If not filtered then a calibration would be needed.

10 Hz IR Avalanche Pulser

10 Hz Avalanche
                  IR Diode Pluser This circuit uses a type of transistor that avalanches and dumps a huge current into a standard T-1 3/4 IR LED producing a much higher output than you could get using a short pulse.  I think the circuit was used for beam breaker type intrusion alarms.  Should have a very long range.
10 Hz IR Avalanche
2N1305 transistor
Vertical resistors left to right: 200, 22, 330
Horizontal resistor 18
Tubular cap 150 uF 6V
Blue mylar cap: 2029ZZ-Z55, 43-7736-45 probably 0.047 uF
The circuit is similar to - Forrest Mims Circuit Scrapbook, Volume 1, pg 57 - 3. High-Current LED Pulser
10 Hz IR Avalanche
                  Pulser PN2222A
Output Pulse from 10 Hz Avalanche
The output pulse is about 50 us wide.  The amplitude does not mean much from this on/off type sensor.

IR Photo Transistor Sensor

IR Pulse sensor

This was made by removing the top of a dead 9 V battery and attaching a QSE156 to ground and +9 volts and leaving the center output lead hanging so that the Rigol Scope probe can be connected to ground and output.  The motivation was to see what the pluse stream is coming from a Nikon SB-900 Creative Lighting System speedlight.  But it was then used on the 10 Hz pulser above.

Ircon DN-DNS30-20C

This is a non contact temperature measurement type S sensor that was part of the InfarRail system. 


Type: ITTC 1144 7235387 575892
A: +
B: -
C: shield

Fluke 87 V DMM red: A, black: B Diode function 0.582V, reverse leads: OL.
The sensor is a Silicon Photodiode (Wiki)
Fluke 67 V DMM in mV range red: A, black: B =  300+ mV under Halogen table lamp, -20 mV under table in sort of dark

The output is slightly higher when the objective lens is used. maye 340 mV instead of 3.5 mV.
The output would be even higher if the calibration screw was backed out so it wasn't blocking some of the IR from the mirror to the photodiode.

Fig 1
Fig 2 Center SLR eyeball port with cap removed.
CAL screw behind name plate.

Mounting looks like 1/4-20 holes for standard tripod.

Fluke 87V DMM: Ohms mode: black A, red B
background OL MOhms to hot 25 MOhms
background 0 uS to hot 50 uS
Fig 3 Temperature sensing end

When I wear my reading glasses I can see a very small circle when looking through SLR port, but not without the glasses.  That's to say there's no diopter adjustment.

Fig 4 Focus tube
To focus - loosen the slotted head (-) screw - slide tube in/out
to remove - loosen the 3/32" hex screw on bottom

18" - inf
7" - 20"
4" - 7"
2" fixed
Type type stamped in knurling at front of tube
Fig 5 Zinc can and end plate.
Fig 6 Cal screw (behind rectangular label) is between the
sensor and mirror.

Note:  Silicon sensors can see slightly longer wavelengths than the human eye can see so using Silicon for 0.7 to 1.9 um makes sense.
They also offer another model that uses an InGaAs chip and that covers 1.5 to 1.6 um.

Wien's displacement law (Wiki) relates the wavelength of the peak emission to the surface temperature of the black body.
So for 0.7 to 1.9 um wavelength the peak black body surface temperature is 4139 k (3865 c) to 1525 k (1252 c).

The emissivity (Wiki) of the hot object will have a very large effect on what any IR sensor sees.  The sensor will work well with a black body but will have problems with something that's more like a mirror.

The part number breaks down to: 0.7 to 1.9 um wavelength Silicon sensor chip with a temperature range of 1100 to 2000 deg C.
The resolution is D/300 when the focal distance is 18 inches.
d = D/300, so at D=18", d = 18"/300 = 0.060" (closest focus distance for P-1 optical tube).
at longer distances the spot size increases in proportion to the distance.  at 3 feet it would be 0.120", at 30 feet it would be 1.2", etc.

Light to Audio

Light to Audio Electro
        Optical gadget
A photo sensor is AC coupled to an audio amplifier that drives a small speaker.  An easy way to tell if there's modulation on a light beam.  The Valantine 1 Radar detector will sense any modulated light, even at video frame rates.

Even though you can't hear 10 Hz, you can easily hear a hammer pounding on a log at 10 Hz.  So this box let's you hear and confirm that the 10 Hz pulser above is working.

LM3909 LED Blinker

Electrical Optical Gadget
        LM3909 LED blinkerThis is just a garden variety LED blinker based on the LM3909.  I think the LM3909 was developed for use in aircraft flashlights.  It seems that whenever I was in a commercial plane there were a number of flashlights mounted to the wall with an LED blinking about once per second.  I also remember reading that a battery would last for it's shelf life while blinking the LED or maybe longer that the specified shelf life.  That indicates that the internal battery loss mechanisims were using more power than the blinker.  It workd using the flying capacitor principal.  The capacitor gets chagred up then it's switched to be in series with the battery so you get a 3 volt pulse to the LED.  Note that connecting a single 1.5 volt battery to an LED will not turn it on.  The circuit needs to be very cleaver to work from less than a volt when the battery is approaching dead.

Electro Optical gadget LM
        3909 LED blinker #2
Yet another LM3909 LED blinker, this time with a different LED installed.
These are fun to have around, kids really like them and I used to give them away.
For many years now the LM3909 has been out of production and the New Old Stock ones go for a big premium.

Electro Optical Gadget
        LM3909 LED blinker on one "D" cell

Here is another LM3909 LED Flasher, this one was started for Chinese New year Feb of 2007 and since it's only July now is still blinking.  These "D" cell blinkers last over a year.

In the 1950s I had a 90 volt battery connected to a resistor and capacitor that blinked a NE-2 Neon bulb in a similar manner.  But that version went for a number of years on one (larger) battery.

Unihedron Nu-B Light Source

Unihedron Nu-B Light

This is a light source with 6 different wavelengths.  The light comes from LEDs that may also have some filtering.  The LEDs are pulse width modulated to sort of equalize the brightness of each.  This is the Nu-B-IR version where the No. 1 LED is white (peak in spectral response around 450 nm), then blue, green, yellow, red and IR (950 nm). 

Note:  To turn off, PRESS AND HOLD THE BUTTON.

Nu-B-IR Inside

The heart is a PIC 12F509 and a very simple circuit.  Since there is no voltage regulator the intensity of the LED depends on the battery voltage ( 2 each CR2032 3V Lithium coin cells).


Solar House Number

Solar House Number
Solar House Number
Vented Ni-Cad
This worked for a while then quit.  pulling the three AA batteries showed why.  One of them had blown it's top (vented) and put slime on the others.   The most probable cause of the battery venting is the cells were enough different in capacity that the weak cell was driven into reverse polarity by the stronger cells.

This is a problem with any battery pack where there are series connected cells.  If one cell is too much weaker that the other cells it can be charged by the other cells which are discharging.

5522540 Solar powered illuminated address number device and mailbox, cites many prior art patents.

Solar Garden Light

Solar Garden
                  Light Circuit
Solar Garden
                  Light PCB
Black battery holder, photo diode, w LEDs green is the back
side of the solar panel.
This may be a sililar circuit dirgram

After reading an interesting analysis of two different Solar Garden Lights I got one to see the high technology they contain.  The interesting ones have a single cell battery to store the power so they include a Switch Mode Boost Power Supply to get enough voltage to drive a LED.

This one has a metal cylindrical frame about 5" dia x 6" high.  A square solar panel a little smaller than 2.5" on a side drives the electronics.  Three AAA Ni-MH cells store the power.  A photo diode senses if it's night.  Two 5 mm LEDs shine down and some light would fall in a circle around the fixture and what light hits the bottom reflector is spread horizontally.  The batteries were dead (this is a used discount store unit) and are now on the C401FS charger, then to the C9000 for discharge analysis and cycling.  Since there's a three cell battery no need for the SMPS.

The batteries showed fully charged in less than 10 minutes.  They are rated at 1.2 Volts and 600 mAh.  Discharging them showed about 33 mAh capacity, so they now are on the Break-in mode of the C9000.  After the Break-In the cells now have 279, 229 and 308 mAh capacity almost 10x what they were down to after sitting.  But it's still half the label capacity.

After installing the batteries the light did not work.  The voltage at the PCB was low.  Rubbing the battery terminals on my pants and after installing rotating the cell in the battery holder fixed that.  Now when the photo diode is put in the dark the two LEDs turn on.  Used Radio Shack Lube Gel (Silicon Grease) on both ends of each battery.  You might think that's an insulator and would stop good contact, but that's not the case.  There's enough spring pressure for the metal to push the weak grease aside and make contact.  But Lube Gel is made without any entrapped oxygen so no air can now get to the joint to allow it to corrode.
Solar Garden
                  Light Working

Working Solar Garden Light

Put outside in a spot that gets some Sun, but only an hour or two per day around Xmas.  Light came one at dusk (noticed it was on at 5 pm) and at 7 am the next morning it's still on.
If each LED was running at 3.3 Volts and 10 ma that would be 20 ma total and if the battery capacity was 600 mah the max run time would be 30 hours.  Off at about 7:13 at dawn probably not because the batteries have run down.

The job of the circuit would be to turn the LEDs on and off based on how dark it is outside.  It's hard on Connect the solar panel to the battery when there's charge to be had in the most efficient manner possible an.  Three Ni-MH cells and the white LEDs are a good match.  For example it's desirable to stop the discharge of Ni-MH cells at about 1 volt per cell, or in this case at about 3 volts.  The LED forward voltage is that of a diode so as the battery voltage goes down as it becomes discharged the LED current also decreases.

My guess is that the number of hours of light depends on how much solar energy gets put into the battery.  During the winter it's only going to get a couple of hours of sun and I've not put in into the ground plumb, but rather with the top pointing kind of toward the sun.  If this solar panel is like the one below for the solar fountain pump (35 mw/sq in) then it's good for about  [35 * 2.5 * 2.5 =] 220 mw for some number of hours.  The voltage at the end of charging three Ni-MH cells is about 4.2 Volts so in the ideal case 220 mw could provide 50 ma of charge current and so it would take 12 hours to fill the battery to 600 mah or considering the battery efficiency more like 18 hours.  Some type of power point charge controller that matches the panel to the battery would help get more charge into the battery.

It's clear that in the winter time the battery is going to be operated most of the time at empty with only a small amount of charge and back to empty.  Being on all of last night was because I charged the battery.

It may be that under these conditions the newer Ni-MH cells that have extended shelf life would improve the performance.  This is just a guess based on the idea that self discharge may be more important when the battery is not fully charged.

A low resistance super capacitor probably would be a better energy storage method.  The idea is that they should have better efficiency that a battery.
27 Dec 2007 light was on again last night about 28 hours total.  It's cloudy today.

1 Jan 2008 - the light has been on every time that it could be that I've checked.  I.e. it's on a little past 5 at night and till 7 something am.  There's no way it's getting enough direct Sun light to charge the batteries and my initial charage would have worn off by now, so the solar panels must generate a small current just from the sky light.

Second Solar Garden Light

New solar Garden Light w/
          Dead BatteriesThis light also uses 3 AAA Ni-MH cells and after charging them the capacity was very poor (around 30 mAh instead of the label 750 mAh).  After using the break-in function on the Maha C9000 the capacity was 420, 451 and 706 mAh which is too dissimilar to use in a series pack.  The problem being that when the lowest capacity cell is discharged the other cells will power it in the reverse direction which rapidly ruins that cell and can cause it to vent.  That's probably the cause of venting in the Solar House number.

This appeared to be a new unit.  It had a red flag, like is used on aircraft "Remove Before Flight", only this one says "Remove This Shipping Tab Before Use" and has one end inside the battery compartment seperating a battery terminal from the battery holder contact thus opencircuiting the battery pack.  Also there are clear plastic protectors on the four solar panels with the legend "Note, Please peel off this protecting film before use."

Photo taken after removing the top from the rest of the light.
You can see that there are solar panels each about 2  1/8" x 3/4".  There's also a photo diode on the top.  Two 5 mm plastic LEDs for the light and three AAA batteries for power storage.  I'm guessing the time and temperature profiles of storage or poor initial quality of the batteries or both resulted in bad batteries when in as new condition.

Solar Garden Light or Marker Light Patents

4486820 Lighting equipment with a solar cell, Y. Baba  (Kyoto Ceramic Co), Dec 4, 1984, 362/183; 362/157; 362/190; 362/276; 362/394; 362/395; 362/431; 362/802; 361/171; 136/244 -
a 4 W fluorescent lamp can be lit for 6 hours with the use of a solar cell of 16 V, 12 W and a battery of 12 V, 90 AH.
4816970 Solar powered light Mar 28, 1989
5065291 Marking Light, J.S. Frost et al (Atlantic Richfield Co), Nov 12, 1991, 362/183; 362/431; 362/31; 362/800; 362/145; 136/291 - small solar panel, minimal one transistor circuit and LED. - The battery voltage must exceed the LED operating voltage and the solar panel voltage must exceed the battery voltage.  simple cleaver circuit.
5221891 Control circuit for a solar-powered rechargeable power source and load, R.W. Janda, Jun 22, 1993, 323/350; 323/906; 320/21; 320/61; 362/183 - 2.7V, 180 ma solar panel, 2 x SubC Ni-Cad cells, 3 transistor control circuit, #1767 2.3 volt incandescent lamp patents 5086267 5041952 use a very similar circuit
5984570 Self energized automatic surface marker Nov 16, 1999
6013985 Sealed solar-powered light assembly, David R. Green (Carmanah Tech), Jan 11, 2000, Jan 11, 2000, 315/149; 315/159; 362/183; 362/800 - two timers, voltage reg, cur lim resistors on multiple LEDs - not too efficient
6406163 Solar cell lighting fixture integrated with heat sink, Tai-Her Yang, Jun 18, 2002, 362/183; 362/374; 362/276 - diminishing effect of solar heat on batteries and electronics
6573659 Solar-powered light assembly with automatic light control, Ion Toma (Carmanah Tech), Jun 3, 2003, 315/149; 362/372 - uses micro controller to dim light to allow it to stay on all night based on charge obtained the prior day.
 6729742 Solar lamp for outdoor use, W. Wismeth, May 4, 2004, 362/183; 362/153.1; 362/431; 136/206 - seperate light sensor diode & solar panels facing different directions

Small Solar Panels

Harbor Freight 91962
                  Solar Fountain Top
Harbor Freight 91962
                  Solar Fountain Bottom of Solar Panels
Harbor Freight
                  91962 Solar Fountain Pump
Sun side pump outlet in center
bottom of panels
bottom with pump

My wife wanted to try out the Harbor Freight 91962 Floating Solar Fountain Pump but it came DOA.  After going thought the RMA procedure they said there was no need to return the dead one so I opened it up in the hope of recovering the solar panels, which worked.  The probable reason for the DOA is very poor soldering at the joint between the panel wires, the pump wires and a 1N4739A 9.1 Volt Zener diode connected cathode to red wires (positive), i.e. normally back biased by would limit spikes from motor that might exceed the solar panel breakdown voltage.

The two 6" x 4¼" panels are connected in parallel and put out about 11.7 Volts in direct sun.  Short circuit current of 165 ma, but those are not at the same time.  So the power out is going to be less than 2 Watts.  The Harbor Freight 41144 5 Watt Solar Battery Charger is 18" x 12.5" or about 3.3 Watts / square foot.  At that rate these two panels would be about 1.2 Watts.

Pump Testing

The pump while pumping water draws:
# AA Batt
H2O Ht"1
240 6.5 27
250 7.6 30
213 8?
Note 1 estimated, not measured

Load Testing Solar Panels

By measuring the voltage across a load resistor the power can be computed as( V * V) / R.
50 W
Desk  Lamp
50 W
Note 1: Not really direct Sun, some tree filtering.  October has less Sun energy than July.
Looks like 35 mw/sq in.  [900 mw / (6 * 4.25)]

5040726 Solar energy powered water fountain , A.T. Dimitri, Aug 20, 1991, 239/17; 239/18; 239/20; 239/22 - seperate solar panel
6435422 Floating Fountain, Mark Wutschik, Aug 20, 2002, 239/23; 239/18 -this floating fountain


I'm using the word Glow to describe light sources that generate light without flame and that get their energy from being excited by photons.  The photons may be visible light, UV light or radiation.
Fluoresce (Wiki) relates to changing the wavelength from one value to another.  For example a fluorescent light changes UV to visible light. (see the 8-Day Aircraft clock)
Phosphorescence (Wiki) relates to a light generating process that stores the external energy and releases it over some time (glow in the dark).

Military aircraft (and probably civilian planes) have phosphorescent paint on the dials and hands of the instruments (see the 8-Day Aircraft clock).  There are also UV bullet style lamps in the cockpit that illuminate the instruments.  This way the pilot maintains his night vision while being able to read the instruments.

Tritium illumination where radio active alpha particles supply the energy to excite a fluoresce in a phosphor or scintillator (Wiki).
Pocket Tool Tritium Light

Optical System Detector

Detects hidden cameras.

Powered by a 3.7 V Li-Ion battery NP120/D-L17.
The supplied universal wall wart supplies 5 V @ up to 2 A and will power the unit and charge the battery.

Optical System Detector
The three way switch has positions:
Steady (this photo)

This detector does not use a telescope or lasers like in the patent, but instead has a 1:1 view and uses LEDs.  The central viewing port may has a red filter, but no magnification.
Optical System Detector Inside

View through Optical System
This is a view through the optical system detector.
Note the central camera lens appears like it was a light.

Also the LEDs appear bright even though the subject camera is not connected or powered. So this device also detects LEDs that have a built-in lens.

To take this photo the camera was focused on the TV camera without the optical system detector then the detector was placed in front of the lens.  The camera took a time exposure.

The 5485012 patent is something I heard about when I was working. I remember this was used in aircraft to detect ground based optically guided weapons.
The part that's not in the patent is that a high power laser can be used to "blind" either an eye or imaging chip.
Note that the patent application was in 1978 but it was issued in 1996, i.e. 18 years later.  These are what I call formerly secret patents.

The 6665079 patent is based on the above method, but is aimed at detecting security cameras.

Aircraft Cockpit UV Instrument Light

I first learned about these in the 1960s while in the Air Scouts.  We met at Moffett Field NAS in Mountain View and one of the things was to try and fly a simulator.  There were UV lights that looked a lot like this one that caused the pointers and digits on the panel instruments (like an 8-day clock) to glow yet there was no white light allowing good night vision.

Popular Science, November 1942, Black Light Aids Night Fighters (Google books & Scroll down), pg 62 - about using UV light in aircraft cockpits. 
"Instrument panels on military planes can be made to glow under black light.  Dials, pointers, and controls coated with fluorescent paint would give off a soft radiance under the rays from an ultraviolet lamp above the pilot's shoulder.  Ordinary illumination produces terporary night blindness in the pilot every time he glances at his instrument panel, making it difficult for him to spot an enemy plane for several seconds.  The same system can be used on naval patrol boats to help the officers keep a keen watch for enemy submarines."
. . .
"Research this summer has produced new types of bulbs particulary plentiful in black-light radiation.  Black-light lamps now range from a tiny three-watt 12 to 16 Volt lamp developed by Eugene W. Beggs and Daniel S. Gustin, of Westinghouse, to a giant searchlight with a white candle power of 350,000,000 capable of throwing an invisible beam several miles."

Westinghouse Patents related to UV & W.W.II

Daniel S. Gustin
1813572 Lamp base, Daniel S Gustin, Westinghouse Lamp Co, 1931-07-07, 220/2.3R; 220/2.1R; 439/615; 313/318.03; 313/318.04 -
2082954 Prefocused lamp base, Daniel S Gustin, Westinghouse Lamp Co, 1937-06-08, 313/315; 264/82; 264/271.1; 362/95; 445/4; 313/318.01; 249/96 - pre-focused flange type for precision applications.  Maybe scientific instruments or headlights for cars?
2110597 Discharge lamp,
Daniel S Gustin, Westinghouse Lamp Co, 1938-03-08, 315/47; 315/32; 315/100; 315/60; 315/335 -
2171237 Vapor lamp,
Daniel S Gustin, Westinghouse Lamp Co, 1939-08-29, 315/48; 313/26; 313/256; 313/629; 313/15; 313/27; 313/266; 315/266 - temperature controlled Sodium Vapor lamp
2259954 Lamp and operating circuit,
Daniel S Gustin, Westinghouse Lamp Co, App: 1938-11-30, Pub: 1941-10-21, 315/102; 315/266; 315/122 - "..ultra-violet lamps of the gaseous conduction type, in which the bulb is provided with a window of extremely thin glass for efficiently transmitting the generated light."
Called by:
5177407 Glow discharge lamp having dual anodes and circuit for operating same, Valery Godyak, GTE,  Sylvania, 1993-01-05, 315/260; 313/491; 313/581; 313/621; 313/632; 315/266; 315/337 - Patent Citations (19),
Eugene W. Beggs
2046363 Precision lamp adapter, Eugene W Beggs, Westinghouse Lamp Co, 1936-07-07, 439/628; 362/306; 362/362; 313/318.03 -

2255431 Molded fluorescent lamp, John W Marden, Meister George, 1941-09-09, 313/485; D26/89; 220/2.1R; 313/493; 313/609; 362/253; 362/260 - building ceiling fixture & bulb
2258765 Radiating apparatus and method, Robert F James, Westinghouse, App: 1934-07-11, Pub: 1941-10-14,  426/248; 4/233; 62/264; 313/112; 313/573; 315/282; 315/336; 315/358; 607/92- "... for the generation of ultra-violet radiations having a desired bactericidal effect without producing detrimental reaction, ..."
2349754 Method and instrument for measuring ultraviolet radiations, Thomas R Porter, Westinghouse, App: 1940-11-30, Pub: 1944-05-23, 250/362; 250/368; 359/350; 250/372; 359/885 - "... output of lamps which generate bactericidal radiations."
2336960 Discharge lamp, Edmund A Reuter, Dewey D Knowles, Westinghouse, App: 1941-08-13, Pub: 1943-12-14, 313/15; 313/42; 313/243; 313/249; 313/256; 313/339; 313/619 -
2349360 Disk-type fluorescent lamp, John W Marden, Meister George, App: 1942-01-24, Pub: 1944-05-23, 313/493; 313/581; D26/79-
2392333 Miniature fluorescent and/or glow lamp, Morehead Chalmers, CBS Corp, Westinghouse, App: 1943-12-20, Pub: 1946-01-08, 315/48; 315/185S -
2401998 Electrial discharge device, Williams Ralph Harry, GTE Sylvania, App: 1943-06-19, Pub: 1946-06-11, 313/310; 313/325; 313/352; 313/491; 313/619; 313/621 - Has the look of the GE UV lamp shown in Fig 4 below.  "a small fluorescent bulb in dimension of the order of one inch by two inches and designed for use on low Voltage D. C. of the order of 20 to 30 volts, this bulb contains argon and mercury and has an anode and a cathode for supporting an electron discharge."
2777091 Ultraviolet lamp, Frederick H Rixton, CBS Corp, Westinghouse, App: 1952-04-30, Pub: 1957-01-08, 315/48; 313/112; 313/575 - for the generation of Ozone.

MODEL 9379640

This one has what appears to be a pre-focused flange type flashlight lamp.  The front lens is clear plastic and behind it there's a blue filter that can be rotated 90 degrees by a rectangular knob.  There's a push on-off switch under a rubber boot at the rear.  The 3-pin cable connector is marked MS3116E8-33P.  The cable is marked:
19200-9379604 and RAYCHEM.  The body is marked (hard to read) MODEL 9379640.

There's rust inside.  The lamp works but the push-button switch is dead and open.
Aircraft Cockpit UV Instrument
Aircraft Cockpit UV Instrument
The front can be removed by pressing in and turning CCW.  The bayonet style lamp "313 919" (@1000bulbs?)can be replaced also.
28 Volt - 0.17 Amp - T3.25 Bulb - Miniature Bayonet Base
The front has date code 4/90.
The 3 screws on the back can be used to center the filament with respect to the reflector in the front part.

Banair Ent - has some cockpit lights

Grimes AN-3038-2A aka C-5A

This is the improved version where instead of rotating the filter cap it can be removed providing much more white light.  Also when the cap is installed there is no white light leaking out.

 Ultraviolet Cockpit Light

Found an eBay listing for a Ultraviolet aircraft cockpit lamp.  Missing the bulb, so didn't bid. Markings:
Ultraviolet Cockpit Light
Type AN 3038-2A  (these were also called C-5 lamps)
Grimes D-2332
Pat 2324384
Found another one new in box with starter controller.

2324384 Ultraviolet screen for fluorescent lamps, Warren G Grimes, 1941-06-30 - (14) "fluorescent lamp" is shown as a filament bulb, like would be used in an old car tail light. 
This is a very specialized fluorescent lamp, not a filament lamp.  It requires a rheostat with a "Start" position.
See: Lights, Lights...- for wiring diagram


Lamp Brightness
+24 VDC
24 VDC ground (-)

Off: Open 2 to 3
On-Dim: 145 Ohms 2 to 3
On-Bright: 33 Ohms 2 to 3
Start: 28 Ohms 2 to 3 & Short 1 to 2

Black to A- (ground): 5 Ohms [starter filament]


TM 1-406 AIrcraft Electrical Systems, Feb 1945
NavAer 08-1-507 Navy Airborne Electrical Maintenance Notes, Sept 1945.  - "...lamp operated directly on 28 VDC without the necessity of an inverter".


Fig 1 New Old Stock UV Cockpit Light & Rehostat-Starter
                  AN-3038-1 aka C-5 Ultraviolet Cockpit Light

Fig 2
                  AN-3038-1 aka C-5 Ultraviolet Cockpit Light

Fig 3 Note filter blocks white light coming up from light table.
                  AN-3038-1 aka C-5 Ultraviolet Cockpit Light

Fig 4 GE MF 5000 DC Florescent lamp
                  AN-3038-1 aka C-5 Ultraviolet Cockpit Light
This is probably a  BAY15D  base.
I have some automotive lamps on order to check that.

Maybe based on patent 2401998 Electrial discharge device

UV Lamp

UV Lamp UVGTL3 8310 E17 Edison base 10.5 V 0.3A 253.7 nm
I think the 6 Watt mark on the box is my typo and should have been 0.6 Watt.  i.e. 10V @ 0.3 A is 3 Watts input so the UV output will be way down from that, such as 0.6 Watts.

UV Lamp UVGTL3 10.5 V 0.3A 259 nm
This is not Wood's glass (Wiki) since it appears clear.

Exotech 100BX Radiometer

This portable instrument was made to compare the actual reflectance of things on the ground with satellite data from Landsat or SPOT satellites by using different filters.
Covers roughly 0.5 to 1.1 micron wavelengths.

AN/UAS-4 Infrared Surveillance System

Uses filters to make multi spectral images.
Covers roughly 0.4 to 30,000 micron wavelengths.


Optical Spectrum Analyzers 
HP 8702B Lightwave Component Analyzer, Electro Optical Network Analyzer


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page created 9 July 2007.