Fireflies flashing in synchrony.
The simulation of firefly flashing using artificial lights and electronic control devices has become relatively easy since the advent of the LED and simple integrated circuit logic chips. I made my first LED type firefly flashers back in 1980 using hardware from Radio Shack. I built a power supply and then experimented with simple circuits that would emulate firefly flashes. This is very easy to do and makes a fun and entertaining science project.
The basic firefly flash simulator consists of simple circuit which used a light emitting diode (LED) in series with a resistor, batter and switch. The switch can be a push button switch that one manually operates to make the LED flash. Such a simple device can actually be used in the field to locate female fireflies which will respond to emulation of a male firefly flash or to attract male fireflies by emulating a female flash response. I've done this many times in my study of Photinus pyralis fireflies. Way back in 1968 I used small flashlights to mimic firefly flashes and still use this method with LED type headlamps or flashlights which are basically just a simple LED circuit as the one I've described housed in a convenient case.
A more versatile firefly flash simulation device can be made by placing a number of LED's in circuit together and making them flash. You can use flashing LED's which is one simple way to create a flash, or you can use a flashing circuit. There are many ways to make a flashing circuit. Basically this involves using a resistor/capacitor along with a transistor to time the flashes. You can also use various integrated circuit timer chips such as LM555. These are available through (Radio Shack #LM555). When you buy one of these IC analog chips they come with circuit diagrams showing you how to wire up a flashing LED.
With respect to this particular IC Radio Shack says,
"Precision monolithic timing circuits capable of producing accurate time delays or oscillation. In the time-delay or monostable mode of operation, the timed interval is controlled by a single external resistor and capacitor network. In the astable mode of operation, the frequency and duty cycle may be independently controlled with two external resistors and a single external capacitor.
The threshold and trigger levels are normally two-thirds and one-third, respectively, of VCC. These levels can be altered by use of the control voltage terminal."
Also available are LM556 ICs which are basically two LM555 control circuits in one 14 pin IC. With respect to this particular IC Radio Shack says,
"These devices provide two monolithic, independent timing circuits of the NE555, SA555, SE555 or SE555C type in each package. These circuits can be operated in the astable or monostable mode with external resistor-capacitor timing control. The basic timing provided by the RC time constant may be actively controlled by modulating the bias of the control voltage input. The threshold and trigger levels are normally two-thirds and one-third respectively of VCC. These levels can be altered by use of the control voltage terminal. When the trigger input falls below trigger level, the flip-flop is set and the output goes high. If the trigger input falls below trigger level, the flip-flop is set and the output goes high. If the trigger input is above the trigger level and the threshold input is above the threshold level, the flip-flop is reset and the output is low. The reset input can override all other inputs and can be used to initiate a new timing cycle. When the reset input goes low, the flip-flop is reset and the output goes low. Whenever the output is low, a low-impedance path is provided between the discharge terminal and ground."
There are any number of LED flasher circuits posted on the Internet which use the LM555 chip. See Various LM555 LED Flasher Circuits. If you are not familiar with how to use LM555 chips see the LM555 tutorial which shows several basic circuits which flash an LED. There is also an good collection of LM555 and LM556 timer circuits with schematics and related data that may be useful in design of LED flashers.
It is basically very easy to make an LED flash to simulate a firefly. Using an LM555 IC you can vary the flash rate with a variable resistor (connected between pin 3 the LED and the ground). Hence you can make the LED flash at any desired interval. For example, to make the LED flash to simulate a P. pyralis firefly very the resistor (aka as a potentiometer) to flash the LED once every 5 to 6 seconds. Us a green LED. These can be purchased separately or premounted in a small panel mount (See Radio Shack 5mm Green LED Model: 276-304).
One little device that I made to use in the field consisted of an LED firefly flash simulator fitted into a small plastic bottle or film canister. These can be made using clear or opaque plastic. I have also constructed these using test tubes and/or specimen vials. The LED will need to stick out of a hole if the vial is opaque. A switch and/or variable resistor can be mounted upon the plastic vial lid. Batteries will fit inside the vial. Thus one has a small water proof firefly flasher that can be adjusted and used for locating fireflies. I've also made similar LED flashers to hand on my dog's collar long before commercial variations were available upon the market.
The basic circuitry for an LED firefly flasher of this sort is shown below:
To control the intensity you can place a variable resistor (potentiometer) where the resistor is shown. You may also use a LM555 IC to make a variation of this basic circuit that will flash the LED at rates which may be either set or adjusted. These devices may be powered using any available low voltage power source including transformers, solar cell, batteries or voltage regulated power supplies, all which may be purchased through Radio Shack. Just remember that if you use a transformer to power your firefly flash simulator it is a good idea to add a low voltage regulated diode to the circuit to avoid damage to the LED and/or IC chips. You can find schematic diagrams for LED flashers in Radio Shack hobbyist manuals. Since those circuits don't belong to me I'll just refer everyone to said publications rather than reproduce them here.
LED flashing circuits can also be made using a other simple cuircuits. The LM3909 IC can be used to make a simple LED flasher. See basic LM3909 LED Flasher circuit. Also see Flasher Circuits for more schematics and basic information about how these type of circuits work. This site also has simple kits you can buy to make simple LED flashers. These kits come with red LEDs so if you want to simulate a firefly, you will have to replace these with a green LED of the same voltage rating. See also the schematic for a basic two transistor LED Flasher as well as the alternate two LED flasher schmatic. There are tons of sites on the net about LED flasher. In fact, if you Google LED Flasher you will find many simple flasher circuits you can experiment with to make simulated firefly flashers. The last time I did this I came up with 179,000 hits!
I've used LED displays for many different applications and exhibits. An easy way to make an LED exhibit is to use foam core board to mount LEDs. For example, lets say you want to make a map which illustrates city or state parks using green LEDs to simulate fireflies and represent park locations. Simply mount a city or state map upon a piece of foam core board and then punch a small hole in each park or interesting area. Around the boarder add pictures of each state park or area of interest which will have a push button switch mounted below the picture such that when the button is pushed, the simulated firefly flash lights up at the park location or other interesting location. For each LED you use a circuit with a switch to tune the LED on and this is powered with a 9 volt radio battery mounted on the back of the foam core board . The foam core board is mounted in an aluminum frame. These firefly flasher photo illustrated maps make great exhibits and displays for areas such as motel/hotel lobbies, restaurants or other places frequented by visitors and tourists. You can also use red or yellow LEDs if you want to use a different theme besides green flashing fireflies.
Other types of displays may be made using foam core boards and mounted LEDs. For example, you may paint a picture upon a piece of black foam core board of flowers and shrubbery with green flashing LEDs added to simulate fireflies. You can use artificial leaves to make three dimensional displays. When such artistic displays are created they provide unique and attractive forms of art that can accent your home or office.
It is relatively easy to make three dimensional flashing LED displays. Simply use an LM555 IC or LM556 IC to make LEDs flash and simulate fireflies. You can also use flashing LEDs. Very nice displays can be created by decorating bushes with flashing LEDs to simulate fireflies. Of course in North America most commonly known and observed fireflies flash while the males are in flight, such that simulated stationary firefly exhibits do not really represent fireflies in flight. There are, however, species of fireflies that do flash and blink upon tropical vegetation, as well as firefly larvae that flash upon vegetation; hence, an artificial firefly display or exhibit using stationary LEDs is not altogether a fantasy and certainly represents a relaxing and entertaining public display.
You can make a multi-LED firefly flasher using an LM555 timer chip to generate an oscillating pulse that is fed into a counter chip (CD4026B combined counter and display driver IC). This circuit will flash up to 8 LEDs; you can also connect the counter/display driver chips in series to flash more LEDs. The logic circuit is shown below:
A resistor/capacitor may be used with each LED to create a more realistic firefly flass simulation as shown below:
Construction of firefly flasher circuits is relatively easy. I recommend begining by building a regulated power supply, buying one from Radio Shack or taking one out of an old piece of electronic equipment. This will give you the 5+ DC volts you need to operate such circuits without damage to any components. You can also use batteries; a 9 volt batter works well for firefly flasher and can be easily attached to the back of framed exhibits. You can also use small transformer with diodes to change the AC current to the DC needed to power logic circuits. Also you will need a piece of proto-board to assemble and test circuits before you solder everything together permently. See the assembly of such a unit below (courtesy of Photozz)
There are many ways that you may make creative application of such LED firefly flash simulation displays. You may string the LED on artificial vegetation or Christmas type wreaths to make a nice wall or door display for interior decoration or hanging on your front door. Another usage is to place the assembly inside a jar or other glass vial to make a "firefly jar" or lamp. Also these may be incorporated into art.
I created the above flying firefly graphic for this purpose. Simply print out art work and attach it to foam core board. Then make small holes through which to insert the flashing LEDs. Such wall art can be powered using a small 9 volt battery. When making these displays I use ultra thin wire which is taped to the back of the foam core board which may be framed using wood or aluminum. This type of art provides a attractive, dynamic decor guaranteed to get attention and may be used in home, office or anywhere else you would like to add the mystique of flashing fireflies. What is especially nice about this is that the same or similar type designs may be marketed upon t-shirts and other gifts and apparel.
There are now available upon the market commercial firefly flash systems which are great for usage in advertising or creating relaxing and pleasant environments. These may also be accented with sounds from nature available as recordings on CD from a number of vendors.
A company called Firefly Magic is marketing firefly flash simulators manufactured by Sigma Two Industries; these firefly flash simulation systems are available to general public as well as to commercial providers of lighting. Although I have not yet acquired one of these systems they seem to be well made and to work using the basic firefly flash simulation technology I have already described. They have various models which may be used indoors or outdoors and come with 7 or 12 green LED to simulate fireflies. Of course if you want to make a firefly tree with hundreds or thousands of fireflies you would have to dish out a lot of cash for many of these units. You may wish to Googling Firefly Simulation. to see what else pops up.
If you want to do a science project about fireflies there are computer programs available which simulate firefly flash behavior. Netlogo has produced a firefly modeling program which they say:
"This model demonstrates a population of fireflies which synchronize their flashing using only the interactions between the individual fireflies. It is a good example of how a distributed system (i.e. a system with many interacting elements, but no 'leader') can coordinate itself without any central coordinator. Though most species of firefly are not generally known to synchronize in groups, there are some (for example, Pteroptyx cribellata, Luciola pupilla,and Pteroptyx malaccae) that have been observed to do so in certain settings. This model generalizes two main strategies used by such insects to synchronize with each other (phase delay and phase advance synchronization, as described below), retaining the essentials of the strategies while downplaying biological detail."
Buzz Skyline, a science fiction writer who has studied computer programing, has developed a Yahoo Firefly Widget as a toy to demonstrate how a grid of fireflies may interact with one another. This is an amusing application which may have future applications.
Although not officially a firefly simulator, I love my Maglites. I've used small and large Maglites in the field when studying fireflies as well as when doing photography or photomicrography. What is nice about a Maglite is they are made out of aluminum so they are very rugged and waterproof. You can use a Maglite in the field to easily locate female P. pyralis fireflies either by blinking the light or by panning it across an area so that any fireflies seeing the light will see it as a flash. I also attach a piece of fiber optics cable to a Maglite to make a small beam. This is useful in creating a small pin-point source of light to mimic a firefly. When I first began studying fireflies in the field many years ago I'd achieve the same result simply by putting a piece of aluminum foil over a flashlight and poking a small pin hole in the foil; the usage of fiber optics is a step up for elitist naturalists who want to go firefly hunting.
I hope this information may be of usage to anyone who enjoys studying fireflies. Simulation of firefly flashes may have many applications and may even be profitable should you want to start your own business providing commercial lighting for advertising or enjoyment. Should you indeed find this material helpful or have any questions, feel free to contact Terry.
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