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Assembling your Time Fountain

All > Tech > Inventions > Assembling your Time Fountain by natetrue
I know you've all been waiting for it... finally, detailed instructions on how to build a Time Fountain!

Remember, I'm selling these as fully assembled units ($200), kits ($100), or just preprogrammed PIC chips ($30). The pre-sale discount period is over, sorry if you missed it! Head over to the Buy page if you're interested.

First, make sure you have all the necessary components. Included in the kits you should have the following:

Mechanical items
- A wooden bowl (treated on the inside to prevent water damage)
- A 12VDC power supply (Note: If you're not in the US, you may need a converter or have to find a local 12vdc power supply)
- A DC pump with ridiculously long power cord
- A nozzle for the DC pump
- A highlighter (source of fluorescent ink)
- 2x Small plastic zipties
- A slanted piece of foam to catch the drips without splashing

Electronic components
- 20x High-brightness UV LEDs
- 2x TIP31C NPN power transistors
- 1x 7805 5v linear voltage regulator
- 1x 4.7 kilohm resistors
- 2x 1.0 kilohm resistor
- 1x 100uF 25v electrolytic capacitor
- 1x 11x18 prepunched PCB
- 1x 18-pin socket
- 1x PN2222A run-of-the-mill NPN transistor, EBC terminal order
- 3x Tactile pushbutton
- 1x Gold-plated pin header, 2x1
- 1x PIC16LF628A microcontroller, preprogrammed with the Time Fountain firmware

Bulk items
- 6ft 24AWG solid hookup wire, paired
- 1ft 1/8" ID clear vinyl tubing
- 0.5in 1/8" OD smaller clear tubing
- 18in 1/16" brass wire, with a bend in the middle

Kits may also include large amounts of packing peanuts.

Ready to start? So am I! Let's begin!
Start by curling the power cord under the bottom of the pump, so it comes out the same side as the pump outlet.
Moisten the suction cups slightly and stick the pump squarely in the center of the bowl. The pump should stick fast.
Thread the tubing onto the bent brass rod so it goes around the crook and down the other side a little ways. The brass rod will be what gives the spout its shape.
Cut the brass just inside the end of the tubing like so. Save the cut piece for later.
Jam the smaller piece of tubing in the end. This will reduce the drop size so they're more consistent.
Cut the other end of the brass so that it won't stick into the pump. You can also bend it slightly to the side to be sure, if you want.
Put the nozzle onto the tube and put that onto the pump.
Get a little creative and put an eccentric bend in the tube. The brass will hold the form for you.
Take the remaining piece of brass and bend it into the same shape. Cut it to go from the bottom of the tube to under where the other end stops.
Here comes the laborious part. We need to attach all of the LEDs to this new bent piece. Tin the cathodes (short leads) of each LED about a half inch from the LED body.
You must also tin an entire side of the brass piece. It's difficult to do properly - make sure you heat the brass up enough to get the solder to flow, otherwise the LEDs will fall off later.
Solder the 20 LEDs equally spaced along the length of the brass. Make sure you only solder the cathodes to the brass. The anodes (longer ones) must remain free.
Put the LED assembly against the tubing, and bend the cathodes around so they grip the tube.

Now bend the anodes so that each touches the next one, and solder them in place. They should all connect together and never touch the cathodes or the brass rod.

Now, make sure each LED is aiming toward where the drops will be falling.
Cut about 2 feet off the end of the pump's cord (discard the power plug on the end), and strip and tin the wires. Connect the blue wire to the anode chain and the brown one to the brass rod.
Grab the gold header and the hook-up wire. Use a blue wire and a white wire, and solder them to the header like so.
Then remove the black plastic holding the header together.

Here you can use a drill to twist the wires together (you only need about 3 feet of twisted wire; the rest will be used as hookup wire and shouldn't be twisted) so that the wires stay together.
Using pliers, jam the lead attached to the white wire through the tubing about an inch above the opening. Position the other wire about 1/4 to 1/2 inch away from the drip opening so that a falling drop will hit it before it detaches from the drip opening. Putting it at a slant helps the drop fall off cleanly.
Unbend some of the LED leads to hold the wire to the tube as it runs down.

This concludes the mechanical portion of the construction. On to the electronics!
This portion will be done with the help of vector graphics for clarity.

Hold the board with the shiny circles facing away from you - that's how these graphics will be presented.
Start by placing the 18-pin socket. Make sure the notch on the socket is toward the bottom of the board as shown. Solder the leads on the back side to keep the socket in place.
Now place the 7805 regulator and the TIP31C power transistors. Make the lettered sides facing you and stick their leads through the board. Solder the leads in place again.
Now place the 3 buttons. They must be oriented correctly - notice that the leads come out of two opposite sides of the button - these must be facing up and down with respect to the above image. Make sure the leads go through where the green circles on the image have indicated. The middle button spans more holes than the side ones, for symmetry.
Now place the transistor and the capacitor. The transistor flat face faces left. Bend the transistor's two outside leads toward the socket, and solder them to the pins they touch (socket pins 12 and 14). Bend the center lead outward so it doesn't connect to the socket.

For the capacitor, take mind that the banded side MUST go to the center pin of the 7805. The other side connects to the bottom "In" pin of the 7805. If the capacitor is in backwards it may explode, so make sure it's right!
Now the three resistors. The 4.7k resistor goes from socket pin 5 to socket pin 12 (to meet one of the transistor's leads).

One of the 1k resistor goes from socket pin 11 to the bottom power transistor, as shown.
Then the other 1k resistor goes from PIC pin 9 to the top power transistor.
Now pull out your hookup wire and make the ground bus around the board like the thick red line shows. You do this from the bottom of the board; it doesn't have to come over to the top of the board. The bus must connect to:

- The ground (middle) pin of the 7805
- The right-side pins of all 3 buttons
- Socket pin 5
- The emitter (top) pins of each power transistor
Now hook up the buttons to the correct pins of the socket. Left button goes to PIC pin 6, middle to pin 7, and right to pin 8.
Connect the 5 volt line (7805 output) to the socket on pin 14.
Grab the part of the fountain you assembled already and connect the drip sensor line. The white wire must be the one jammed through the tube, and the blue one should be the one that the drips will touch as they fall.
Cut the connector off the end of the 12V adapter and solder the wires to the 7805 as shown. Use a voltmeter to determine which lead from the adapter is positive and which is negative. The positive lead goes to the Input (bottom) pin of the 7805. The other one goes to the ground (center) pin.
Finally, connect the LEDs and pump to the board. The pump Blue wire goes to the center pin of the top power transistor; the Brown wire joins with the Blue wire of the LEDs and they are connected to the power supply positive voltage (bottom pin of the 7805). The Brown wire of the LEDs goes to the center pin of the bottom power transistor.

You're done! Put the PIC chip in the socket so that its notch lines up with the socket's notch.

There's still some adjustment to be done, so follow these instructions to get your fountain working.

Testing your assembly

Plug in your Time Fountain with no water in it. You should see the UV lights flickering and the pump should gradually speed up then stop. If this happens you've built your fountain correctly so far. You can proceed to the moister section. If not, check the Troubleshooting section for possible solutions.

If you bought an assembled fountain

If you bought a pre-assembled fountain, you may be disappointed to find that it is not fully assembled. You will have to put the pump into the bowl yourself, sorry! Everything else is built, though.

Using your Time Fountain

Start by filling the bowl with water. It should come to within a half inch of the top of the bowl. You'll have to add water periodically as it evaporates and/or splashes out.

Chew the back end off of the highlighter and extract the ink sponge. You only need a few drops to get the water very fluorescent.

Plug the fountain in (make sure your hands aren't wet). The pump should power up and slowly build until the water starts dripping out. If the water starts spraying everywhere then you don't have the sensor correctly positioned - the water stream should hit the sensor when it starts.

The Time Fountain automatically chooses an initial speed for the motor but it's up to you to fine-tune it to a stable drop stream. Use the left and right buttons on the fountain to slow down or speed up the pump. You know you have it right when the drops appear stably frozen in mid-air. You may also have to experiment with sensor positioning.

Press the center button to enter "Stable" mode. In this mode the drops will stay frozen, and you can use the left and right buttons to move them up and down.

If you press the center button again, you will enter "Slow motion" mode, where the drops fall in slow motion. Here the side buttons do nothing.

The last mode is "Backwards" mode where the drops will move backward in time. Again, the side buttons do nothing.

Hitting the center button again will return you to "Motor Adjustment" mode.

That's all! I hope you enjoy your Time Fountain as much as I do mine.

Troubleshooting your Time Fountain

Okay, so something went wrong with your Time Fountain. Here are some common problems:

When I turn on my Time Fountain, the pump gets faster and faster then stops.
Something's wrong with the sensor. For the sensor to trip, it needs a bridge of water between its two leads - the white one inside the tube and the blue one hanging in space below the drip opening. Make sure that your sensor is wired correctly and that it is positioned to be hit by falling drops before they disconnect from the drop opening.

The LEDs don't light up at all.
Either the LED wires were installed backwards, or there's a short circuit - check that the LED anodes are connected to the power supply and that the cathodes are connected to the center lead of a power transistor. Also examine the leads on the LEDs for a short circuit.

I can't get the drops to freeze in mid-air.
This could be a sensor misalignment - the sensor might be too far or too close to the drip opening to get a good on-off-on-off reading when drops go by. Also try using slower pump motor speeds to make bigger drops.

If you have any other issues, please contact me at or post a comment below and I will be sure to help you out.

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Posted by kleucht 8 years ago ( 24-Jun-2007 09:31:24 )

Very nice and detailed instructions.

Posted by firoz 8 years ago ( 05-Jul-2007 01:13:58 )

thanks for such detailed explanation.
i have a doubt.can i use the above code to control only LED by means of drop problem is,i have bunch of small AC pumps.and i want to use them for i'll make the constant dripping system(say 10 drops per sec.and using the drops sensor and the buttons can i get those back/forward effects.
ultimately i want to use the pump independently,not controlled by is this possible with the current available code.
thanks once again for your effort.

Posted by samuelterminator 8 years ago ( 26-Aug-2007 17:11:53 )

I was wondering would it affect anything if you covered up all the wires on the back of the tube with electrical tape. Just to make it look clean?

Posted by kokopellithemuse 7 years ago ( 22-Oct-2007 15:15:32 )

Where did you get the DC pump? I had a look at the local pet store but all the pumps there were AC.

Posted by tumbawamba 6 years ago ( 22-Dec-2008 13:49:32 )

Hi Nate,

you dont answer mails.. I have ordered time-fountain-kit month ago. Got no confirmations, no infos on delivery times. How to get in touch with you?

This comment was edited at 2008-12-22 14:00:36

Posted by syslord 6 years ago ( 09-Jul-2009 12:25:37 )

The resistors values are wrong in the image.
Also I suggest one image of the finished board without overlay.

Posted by datura 6 years ago ( 13-Sep-2009 19:00:02 )

It works! Thanks, Nate. I found it easier to wrap the LEDs around the plastic tube before soldering to the brass rod. I ended up soldering those things like 3 times before I got it right. Also I agree with syslord, the resistor values are wrong in the image and a pic of the completed board would be helpful.

But the important thing is that it works and I'm having a fun time playing with it!

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