Harold "Doc" Edgerton, an American electrical engineer and photographer was noted for creating high-speed photography techniques. He developed and improved strobes and used them to freeze objects in motion so that they could be captured on film by a camera.
The 'Piddler' machine he created more than 50 years ago uses a stroboscopic technique to form optical illusions of levitating water droplets, slowing the downward flow of water as well as reversing the flow of water to move upwards to defy the laws of gravity. This inspired us to come up with our design of a Time Fountain.
With the water droplets in reverse, moving against gravity, it looks like the fountain is going back in time. Hence it is coined as a 'Time Fountain'.
You may view the following YouTube to see a 'Piddler' machine in action.
We searched online for Time Fountain projects and found most setups are quite large. Fluorescent dye is often used in these projects to made the water droplets more visually appealing.
For our project, we attempted to design a compact Time Fountain which should be small enough to be carried around and we will not be using fluorescent dye as we hope kids can play with the water without any health concern. We will be using inexpensive small water pump and control valve to create a 'stream' of water droplets to be as uniform as possible and encase them in a small enclosure.
To build this project, basic electronics component soldering skill and some knowledge on using the Arduino is required.
You may like to view the following YouTube video to see what we will be building.
For this project, we have misused a solenoid valve to turn on and off the flow of water at rapid interval of 45 cycles per second in order to create a 'stream' of water droplets.
If you like this instructable, please vote for us in the Creative Misuse Contest at the end of this instruction. Thanks.
How it works?
No camera tricks are involved here. All these are stroboscopic technique optical illusions which we are able to see right before our eyes.
Water droplets are created by pumping them out of a tube at rapid and regular intervals to form a steady 'stream' of water droplets.
If the droplets are pumped out at a frequency of perhaps 45 Hz and illuminated with strobe light flashing at the same frequency, the droplets will appear to be essentially motionless and seem to be levitating in mid-air. When we see a droplet levitating in mid-air, the droplet is not exactly the same droplet. As the strobe light frequency is synchronized with that of the the falling droplets, every time the light is on it shows us the image of a different droplet at the same position. When the light is off, the droplet keeps falling and another replaces it.
By off-setting the frequency of the strobe light to a slightly lower frequency, the water droplets will appear to fall in slow motion. This is because the next droplet is actually slightly lower than the previous droplet when the light comes on and our brain interprets that as the same droplet moving downwards.
If the strobe frequency is off-set to a slightly higher frequency, the water droplets will appear to reverse back into the tube. This is because the next droplet is actually slightly higher than the previous droplet when the light comes on and we will perceive that as the same droplet moving upwards.
If the strobe light is turned off, the rapid water droplets falling will look like a continuous 'stream' of water falling to our unaided eyes due to Persistence of Vision.
To a small percent of people with epilepsy, exposure to flashing lights at certain intensities or to certain visual patterns can trigger seizures. This project requires flashing of the LED strip lights at quite a high frequency which most people will not be affected by the flashing light. However, if you experience discomfort from direct or indirect light from the Time Fountain, you should stop looking at them immediately.
Step 1: Building the Electronic Circuit Board
As with most of our projects, we will be using our favorite Arduino Nano board for this project due to its small form factor and ease of use.
The schematic diagram for our project can be found above. We have designed the electronics DIY kit for this project which will be available at our Tindie store if you prefer something easier to work with or you may opt to wire everything up on perfboard yourself. We will not elaborate on how to build the circuit onto a perfboard here.
With this circuit we have a basic strobe light with duty cycle (brightness) and frequency both adjustable via two potentiometers. Another potentiometer is used to control the water pump intensity.
We used warm white single row DC 12V LED strip light with SMD 5050 LEDs which has 120 LEDs per meter for our project. We need 2 short LED strips containing 12 LEDs per strip.
A momentary push button switch is used to select the mode of operation for our Time Fountain.
You may check out the following YouTube video on how to assemble the electronics components onto the PCB board we designed.
The following are to be observed during PCB assembly:
- Ensure the orientation of the capacitor, 3 MOSFETs and Arduino Nano is correct.
- Ensure all components are soldered onto the TOP side of the PCB.
Step 2: Main Panel Assembly
To build a beautiful Time Fountain, the water droplets are to be created to be as uniform as possible in terms of shape and size and should be pumped out at rapid and precise intervals to form a steady 'stream' of water droplets.
It is sad to admit our Time Fountain design is not able to achieve the above requirement well but we are still very amazed with the optical illusions it can create.
For our Time Fountain, we will be using a small submersible water pump to draw water through tubes and tube adapter up to a small normally closed solenoid valve. The solenoid valve can be energized to open and allow the water to flow through. For our design, our valve will be turn on and off 45 cycles per second to produce a 'stream' of water droplets.
The water pump, tubes and adapter, PCB module and solenoid valve shall all be fitted onto a 3mm thick acrylic main panel of size H270mm x W65mm . Details on the main panel can be found in the PDF file below. Two short LED strips shall also be installed onto this panel. For this project, we used warm white single row DC 12V LED strip light with SMD 5050 LEDs which has 120 LEDs per meter for our project. As our Time Fountain is not large, we only need 2 short LED strips of around 0.2 meters long each. You may use LED strips in any color of your choice.
We also have a photoelectric sensor fitted onto this panel to detect objects from the back. This sensor have a detection distance which can be adjusted to between 3 cm and 80 cm. It is added to create some fun and magic to the project. For this project, we have programmed our micro-controller such that the 'stream' of water droplets shall appear to slowly flow upwards against gravity if the sensor detection path is interrupted.
The wiring diagram for the PCB module to connect to the water pump, solenoid valve, LED strips and the photoelectric sensor can be found in the images above. The sensor comes with a long length of cable which is trimmed to around a 160mm long to fit with a short length of slack. We will also need wires of around 160mm for soldering to the solenoid valve and LED strip light.
The layout of the parts as we set them up can also be found in the images above.
You may check out the following YouTube video on how we assemble all these parts onto the main panel.
Note that the solenoid valve is mounted with the outlet nozzle pointing downwards at an angle with a short length of tube attached to aid in the flow of the water droplets.
Step 3: Program the Arduino Board
We can use the ATmega PWM registers directly to change the frequency and duty cycle of the PWM signals for control of the solenoid valve and LED strip light. You may visit https://www.arduino.cc/en/Tutorial/SecretsOfArdui... if you are interested to know how to use the ATmega PWM registers directly.
For our project, instead of using the ATmega PWM registers directly to change the frequency and duty cycle of the PWM signals, we will be using the Arduino PWM frequency library created by runnerup. For details on this library, please visit this thread at the Arduino forums: http://arduino.cc/forum/index.php/topic,117425.0....
The Arduino sketch for our project can be downloaded in the link below:
You also need to download and install the Arduino PWM frequency library from https://code.google.com/archive/p/arduino-pwm-frequency-library/ for the JF Time Fountain Arduino sketch to compile successfully.
We used Arduino IDE version 1.0.6. to compile successfully for our project.
Finally, upload the program to your Arduino Nano/compatible micro-controller board. We will not elaborate on how to upload the program into your micro-controller here as this information is easily available online.
Step 4: Test Main Panel Assembly
With the Arduino board loaded with the JF Time Fountain program and our main panel fully assembled, we will proceed to test them to make sure everything works correctly before we embark to build an enclosure for it.
We will need a 12V DC power adapter to power up our Time Fountain. Here, we used one which is rated for 12V DC 2A. You may need a power adapter of a different rating if you use different parts or components for the project.
We also need a shallow basin or tray filled with water. We used a table tray purchased from IKEA. Place the Time Fountain in the tray and fill it with water until the water level is at least above the intake nozzle of the water pump. However, ensure the water level is not higher than any electrical/electronic wiring or parts except the submersible water pump. Plug in the power adapter and power up your Time Fountain.
The water droplets falling out may not be steady initially if there are air pockets in the water pump, solenoid valve or tubes. We will need to let the water pump run for a while and use the potentiometer to adjust the water pump intensity to almost maximum and then power down and up our Time Fountain a few times to get rid of any air bubbles in the tubes in order for the water droplets to fall out more steadily. It can be quite frustrating at this stage to get the water droplets to flow out steadily. Initially, we almost gave up on this project thinking it will not work at all with this setup.
Do not worry if the water droplets are not falling out steadily yet. With the main panel assembled into the enclosure which we will be building later, the sturdy support should aid in making the flow more stable.
There are 3 potentiometers on the PCB module mounted on the main panel. The photo above shows the function of each potentiometer.
The first potentiometer from the top is used to change the frequency of the strobe light provided by the LED strips. When this potentiometer is turn fully anti-clockwise, the strobe frequency is low and we should be able to observe some flickering/flashing of the lights and as the potentiometer is slowly turn clockwise the flickerings gradually goes off.
The second potentiometer is used to adjust the brightness of the LED strips. Ensure the LED strip brightness is able to change if the potentiometer is adjusted.
The third potentiometer is used to control the water pump to adjust the flow rate of water to the solenoid valve. Ensure the water flow can be regulated.
The momentary push button switch on the PCB module is used to select one of the four modes of operation for our Time Fountain.
Mode #1 - Basic normal mode. The strobe frequency can be changed via the potentiometer to create optical illusions on the flow of the water.
Mode #2 - Demo mode. The Time Fountain shall loop through some optical illusion displays.
Mode #3 - Levitation mode. The water droplets shall appear to levitate in mid-air.
Mode #4 - Light off mode. The LED strip light shall be turn off but the water will keep flowing out. In this mode, the water droplets will appear to be just a continuous stream of water flowing downwards due to persistence of vision.
The photoelectric sensor will only work under mode #1. If the detection path of this sensor is interrupted by blocking it with any object, the frequency of the strobe shall gradually increase and the water droplets will gradually appear to reverse upwards to move against gravity.
Ensure the main panel is supported securely upright during testing. It may be disastrous if the main panel were to fall flat into the pool of water with everything powered up.
Step 5: Build the Enclosure
We will need to make some fixture to hold the assembled main panel upright.
We used 3mm thick acrylic sheets cut to size of H300mm x W65mm to build a simple enclosure to house the main panel.
The dimensions for the enclosure panels can be found in the PDF files below.
You may check out the first part of the following YouTube video on how we build our enclosure.
Our enclosure is simple. If you are creative, you may use other materials to build your own unique enclosure but as the enclosure is partially submerged in water, the material you use must be water resistant.
Step 6: Final Time Fountain Assembly
The final step for the assembly is to install the assembled main panel into the enclosure.
You may check out the second part of the YouTube video from the previous step for installation of the assembled main panel into the enclosure.
Step 7: Be Amazed
With our Time Fountain fully assembled, place it in a basin or tray filled with water. Ensure the water level is above the intake nozzle of the water pump but below any electrical/electronics parts except the submersible water pump.
Plug in the 12V DC power adapter and power up your Time Fountain.
If everything is in place, be amazed to see the water droplets levitate in mid-air, fall downwards in slow motion or move upwards to defy gravity right in front of your eyes by changing the frequency of the LED strip strobe.
To add some fun to the project, we build a stand to support a small cup pivoted low at the sides to catch the water from our Time Fountain. We stuck a coin at the bottom of the cup as a counter-weight so when the cup is filled with water, the cup will swing to one side and empty the water in the cup and then return to the upright position. We will not elaborate on how we build it here. You may see it in the image above and build something similar or even something better yourself.
Hope you enjoy building the Time Fountain and amaze your family and friends with the optical illusions.
If you like this instructable, please vote for us in the Creative Misuse Contest. Thanks.
Step 8: What's Next?
The Time Fountain we built have quite basic features. You may explore to build a more interesting Time Fountain.
It is also not perfect yet. You may want to explore how to improve the quality of the stream of water droplets.
We are not too handy and creative. The enclosure we designed is basic and simple. You may design and build some fancy enclosure with a beautiful pond to hold the water instead of using a basin or tray..
Stroboscopic techniques are employed to form amazing optical illusions in many projects. You may check out our SLOMO Frame project which uses a similar technique to make light objects placed in a picture frame move in what appears to be slow motion. This project is available at https://www.instructables.com/id/IKEA-Frame-Hack-SLOMO-Slow-Motion-Frame/.
You may check out the following YouTube video to see our SLOMO Frame in action.
Be creative and you may come up with more amazing projects employing stroboscopic techniques.
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