p.2 #6 · Flying projectile pass through a falling droplet.
This work is fantastic.
And it's great that you share your setup details. It's very clever and well done.
Have you got a "bark-back" diode around the inductor to protect the driver transistor? I guess now that I read the thread more carefully, it sounds like you've added a snubber. But a diode across the coil is also always a good idea when driving any solenoid or relay coil with a transistor. I recommend mounting a snubber and/or diode right at the solenoid itself with as short of leads as possible.
The speed of this FET actually makes things even worse. The very fast turn-off time can create a more difficult to "tame" inductive spike from the coil as the magnetic field collapses when you turn the transistor off.
You could add a circuit to slow down the turn-off of the FET. That will make it a lot easier for the built-in protection diode to act. When things are as fast as these FETs can be, just the lead length between the FET and the load can create damaging inductive spikes. Slowing the turn-off time down really makes it a lot easier on everything. But you may well already be aware of all of this
Also, what sort of a flash are you using? Your shots appear to be very nice and sharp so I'm guessing you're using an older thyristor type flash instead of one of the modern units. The new flashes seem to lack the ability to emit a very fast pulse. The older or simpler ones seem to be the best.
In any case, thank you for posting this. Your work is wonderful and I look forward to more posts. They're spectacular and interesting.
p.2 #10 · Flying projectile pass through a falling droplet.
JimH. wrote:
Have you got a "bark-back" diode around the inductor to protect the driver transistor? I guess now that I read the thread more carefully, it sounds like you've added a snubber. But a diode across the coil is also always a good idea when driving any solenoid or relay coil with a transistor. I recommend mounting a snubber and/or diode right at the solenoid itself with as short of leads as possible.
Thanks Jim for the good info for the fet protection.
I've now a snubber citcuit. I know about a diode over the coil but in that case i's more complex as the magnet induction need to fall very fast to zero just at the moment the projectile pass the middle of the coil. The time is now near 1.5 msec from the start. If you put a diode over the coil the magnet field fall to slow and the projectile brake and even return to the centre of the coil instead of flying way An other methode is to put a highvoltage transorb of 300V over the fet but at this moment I'dnt have one in stock. But with the snubber circuit added all seems to work safe now.
p.2 #11 · Flying projectile pass through a falling droplet.
Thanks for all the nice replay's!
The dropper unit is tested now. And yes, it's works super! Now I can give 2 droplets at a precise time interval. Therefore I've to use a second laser system just below the dropper to detect the start of the first droplet. This dropper reference point give the start to the programmed second droplet timer. The used value now is into the range of 30 to 60 msec. But the results are super. Every shot give a double splash like this examples:
Oké, this are only examples, now I've to work on other compositions, lighting and color but this will be done into the next day's.
I will test new lighting. Now I use the SB80DX and the SB800 set at 1/64 or 1/128 power to keep the short exposure times but I've other idea's, but need to test this first before giving the information. I like to limit the exposure to 100 usec max. camera is set now at F20 ISO100 and 1/250 sec.
p.2 #12 · Flying projectile pass through a falling droplet.
frans_vdm wrote:
Thanks Jim for the good info for the fet protection.
I've now a snubber circuit. I know about a diode over the coil but in that case i's more complex as the magnet induction need to fall very fast to zero just at the moment the projectile pass the middle of the coil. The time is now near 1.5 msec from the start. If you put a diode over the coil the magnet field fall to slow and the projectile brake and even return to the centre of the coil instead of flying way An other methode is to put a highvoltage transorb of 300V over the fet but at this moment I'dnt have one in stock. But with the snubber circuit added all seems to work safe now. ...Show more →
Excellent!
Yes, one of the serious drawbacks of using a diode around the coil is that it allows the magnetic field to collapse very slowly by maintaining a path for the coil current. I'd say you've got this all figured out very well. And Transorbs are fantastic. They're extremely fast and you can select the exact voltage you want.
Even an MOV might do the trick for you in this application. They're good for clamping the peak voltage while allowing the field to collapse rapidly. But it sounds like you've got it solved already. You have obviously put a lot of thought into this all! It's an amazing project and inspirational to see. I hadn't considered how you'd need to stop the magnetic field so fast for this to work as a projectile launcher
The new shots are beautiful. I love the look of the 2nd drop impacting the splash from the first one. It's a fantastic effect.
I just had a thought: If you had two drop dispensers, and some way to alter the trajectory of the second drop so that it'd strike the same place as the first drop, you could use one color for the first drop and another color for the 2nd drop. I wonder if you could use some kind of electrostatic deflection to "aim" the 2nd drop. Static affects water very greatly, so it might be possible. Perhaps one could even create a pattern of drops by having an X-Y deflection system for subsequent drops.
I guess it'd be like some of the super high-speed ink-jet check-printers that use electrostatic deflection of the droplets to form the characters. Anyhow, that's all just daydreaming.
Again, thanks for posting your wonderful shots and the details of your setup! It all just gets a person thinking and dreaming
p.2 #13 · Flying projectile pass through a falling droplet.
JimH. wrote:
I just had a thought: If you had two drop dispensers, and some way to alter the trajectory of the second drop so that it'd strike the same place as the first drop, you could use one color for the first drop and another color for the 2nd drop. I wonder if you could use some kind of electrostatic deflection to "aim" the 2nd drop. Static affects water very greatly, so it might be possible. Perhaps one could even create a pattern of drops by having an X-Y deflection system for subsequent drops.
I guess it'd be like some of the super high-speed ink-jet check-printers that use electrostatic deflection of the droplets to form the characters. Anyhow, that's all just daydreaming....Show more →
Thanks Jim for all the proposes.
I work on the same kind of solution for colored multidrops. In the past I've used manual color injection for my waterfigures but for this droplets i'ts going to fast, so a magnet controlled unit is need. This units are under development now. They consist in an electromagnet and a syringe system and are hang up just under the falling droplet. A few moment before the droplet reach the needle with the paint an impuls to the electromagnet is given. Both droplets are mixed and falling together giving a beautiful color gradient. Multiple color injections systems can be mounted so the colors can by programmed in advance. But all this units take time to develop.
A detail of the current single dropunit is given here:
The first droplet is given manual with a manual pressure on the bellow on the right side and the second droplet is given by the controller and the speaker at an interval between 30 and 60 msec. A second laser system is need for the correct detection point:
But I need more time to realise all this nice idea's
Frans.
p.2 #14 · Flying projectile pass through a falling droplet.
That's great. Your construction and designs are works of art just as your resulting photos are
I love the gradients of color you get in the splashes such as the examples in this thread. They look like fine hand-blown glass sculptures.
I like the idea of the syringe depositing a tiny bit of pigment into the falling drop as it contacts the needle. As you say, it should produce beautiful gradients of color in the drops instead of them being all one uniform color. So that's a wonderful approach, I think, because those gradients and bands of color add a lot to the beauty of the forms that you capture.
I know exactly what you mean about all of this taking time to develop. I tend to have a lot more ideas than I ever have time to realize them! It's wonderful to see how your equipment is designed and built and the fantastic results you're getting.
p.2 #16 · Flying projectile pass through a falling droplet.
Thanks MichAg92!
But I will added more colors next time!
JimH. wrote:
I know exactly what you mean about all of this taking time to develop. I tend to have a lot more ideas than I ever have time to realize them! It's wonderful to see how your equipment is designed and built and the fantastic results you're getting.
Problem is that some ideas take a lot of time to make and at the end todiscover that in no way it's works!
Today I found a solution for the small color pigment droppers. Key of the units are the fine adjustment of the liquid steps on a index control button. Now I have to test the pressure need for the electromagnet to see if it works with the available power of the magnet into this short time interval. Of course I put an extreme overpower for an ultra short time ( 150 or 300V on a 6V electromagnet for 2 msec). It contain the magnet and a modified part of a insulin syringe. I hope to finish this unit into 1 or 2 weeks. Fortunately all this timings can be added into my Altera FPGA chip controller ( now only 9% used). Programming all this timings is the easiest part! For sure if it's works I will give more details and pictures.
Frans.
p.2 #17 · Flying projectile pass through a falling droplet.
I read through this thread and your first images of the projectile in the drop of water are great - the 3rd one when you got the timing down is great ! I wasn't as impressed with the shots with the soap but you gotta try to see what it does. Your shots of the simple drops are great!!! that first one with the yellow / orange look is great - looks like the new budweiser logo. The last images with the white (double drops) are just beyond belief! SWEET - AWESOME - not sure what else to say about them. Keep up the excellent work!
p.2 #20 · Flying projectile pass through a falling droplet.
Thanks wsw_wyatt_earp, Rob Sinclair and stits.
Not all thinks always works. Like today, after a full day labor on the new color pigment injector, my tests fails. The power on the magnet is too low to move the piston from the pigment container and to form a small drop. I'm disappointed but will dream this night on an other solution.
This morning I've put a big order of high bright power leds to make new tests on lighting. One led is about 240 lum. I will put this leds very close to the figures as color lighting help. See what this will gives...
