Dynamic camera movements can really increase the value of your production, but also requires more man power (and budget). The ideas within this article are based on setting up a second camera on a Video Slider without having a second Camera Operator (completely unattended). This 'B' camera angle offers dynamic movements so that you can cut away to the footage when needed. This is an excellent idea and a few companies are already on the ball with new products (coming soon).
First up is the Kessler Parallax system that offers a mechanical Parallax panning motion to your video head as it tracks left and right. Neat trick, but to get this fully automated you'll have to tie in to the Kessler Oracle system, which not only adds additional cost in the end, but extra equipment to assemble during production. More info at https://www.kessleru.com/2013/09/update-kessler-parallax/
Next we have the RedRock Micro One Man Crew. This motorized slider offers a curved (Parabolic) track to keep your subject in focus as it moves left to right (and back again). Completely silent with options to set a limit on range, and control speeds. The best part is that it is an all in one solution that's quick to set up and quick to store away. Starting at $1500 dollars (seen here), it carries a decent price tag, but it will save you from hiring an extra person to man a sliding camera. After finishing this article, you may come to realize the price to be very reasonable. More info at https://store.redrockmicro.com/OneManCrew
Buy- RedRock Micro One Man Crew Motorized Parabolic Slider
Now i've been asked several times if this was something that could be built at home (a.k.a DIY). Here i'm going to introduce a very basic concept on how i've managed to accomplish the same 'ping-pong' / 'back-forth' effect on a cheap DIY motorized slider kit (seen here) with an additional $10 dollars worth of switches, wiring, and a relay, and absolutely no programming. It's basically a simple and dumb electro-mechanical system.
Unmanned, unattended, looping, automated, it all sounds pretty good. Yet you can see how this basic system fails to provide many of the 'Smart' features of the more expensive products coming to market. On the flip-side, one advantage is that with this basic circuit one can expand this idea outside of just a typical slider. (Yes i'm already working on those ideas).
First Test - Building the Circuit Automated Looping Motorized Slider
Here's a schematic of my layout. You'll notice how each side of the motor has both negative and positive from the battery, but only one set is active from the DPDT.
Click for Larger Version
Two 3 Pin NO+NC Momentary Micro Switches (as found here) at each end reverse the polarity of the motor each time they are triggered.
Example of 3 pin NC/NO Momentary Micro Switch
A 12V DPDT Relay (as found here) is either 'Always ON' until the slider reaches the opposite switch which drops power to the relay.
Example of 12V DPDT Relay with Socket Base
In one direction, the relay is technically 'STUCK ON' by way of a tricky little feedback loop in the circuit. To turn the entire slider on or off, i'm just using the switch from the battery. In this example, i'm not using a speed controller, but one can easily be added.
[Update] If you have trouble following the schematic, I have another article with an easier way to create this setup. Others have successfully got their own sliders working. Check out the other article (found here).
@Emm. Got the auto reverse working , but just wanted to point out why some were having errors with your diagram. the diagram here and the one one with the pin layout in your updated version that works has one small difference, the normally closed end of switch A connect to two different places, In the corrected version it connects to the normally closed end of the top switch in this diagram , and here it is connected to the normally open. connecting to the normally closed end is the correct way. While it is a bit old , some students might use this and be led offtrack by error.
@CorduroyPanda , built your circuit, the relay was vibrating and not being stable, tested in circuit wizard and the say it will not work, On your diagram which are the common contacts for the switches of the relay?
The potentiometer add on to this will be much appreciated Emm! I tried to put the speed controller before the relay circuit. It works but when you drop the voltage using the potentiometer (below 7-8 volts I think) the relay starts to malfuction. When I put the speed controller after the relay circuit and the polarity starts to change due to the switches (-,+) instead of (+,-) for example the speed controller circuit starts to fry!!! At least the input wire. I guess it doesnt like that! 🙂
But a solution to this would be great! In every other aspect it works just great. A great post and a great DIY project.
@ErnieHorning - I agree it doesn't make a whole lot of sense and it looks confusing - but I can guarantee it works. This is a design I came up with myself. Others are already using this schematic with their slider systems and here's an update on the project in which you don't need to understand how it works. httpss://cheesycam.com/cheesycam-diy-auto-reverse-polarity-motorized-video-slider-update/
It’s taken a bit of time trying to understand your schematic and I now understand why it’s so confusing. The initial motor ground is connected to the wrong side if Switch 1. As is, the motor will run but when Switch 1 is pressed, it will short out the battery through the relay contact.
@Adjit - I still have to put this schematic together. Haven't had the time just yet.
@Emm Do you know what the circuit would look like if I wanted to add a potentiometer to it?
@Duey - I am getting a new slider from ServoCity, so i'll try to add in a speed controller into the schematic. I believe the easiest way to add one is use one without reverse since the circuit will change polarity on it's own. Hopefully I will have this new slider kit in a few weeks.
Thank you so much for this, it is exactly what I was looking for. I bought a speed controller for mine, not the servo city one, but this one...
How would I add that to this setup?
@Cliff - I will have a new tutorial for you in a few days.
Has anybody gotten this to work? I've been trying but am not having much luck. Thanks
I'm already envisioning cheesy ways to add parallax with elastic bands!
@MIke Mikkelson - DPDTs are pretty straight forward, easy to test if it's bad or not. I just got another motorized slider that I need to build, and i'm just waiting on some parts to do another video. I will show how I have mine setup and hopefully it's more clear.
My DPDT relay showed up today, and I spent some time tonight wiring it up the same way you did. Wah, wah, wah... Didn't work. I must be missing something, and I've been troubleshooting for over an hour. Going to put it aside until tomorrow, and may try Panda's method with a diode. I'd hate to think that I spent a few weeks waiting for that DPDT relay to show up from China, and it's faulty. Probably me, but who knows.
Here is a link to my diagram:
Both work, as they use pretty much the same parts: two micro-switches, one Double-Pole-Double-Throw 12V relay, a motor, battery and diode.
Notice on the right micro-switch there is a diode placed just under the common terminal.
The point of the diode is to limit the direction of the current. Using this schematic without the diode will cause problems with the relay latching.
@Corduroy Panda - Sounds cool, would love to see what you have going on. As far as my setup, I actually don't have two wires going to the motor. I'm jumped at my relay which auto switches the polarity. I just have the schematic showing where the feed is coming from. I'll try to show a cleaner setup soon. I have to redo the wiring.
With some help, I have rigged a simpler circuit that uses a diode on one of the common terminals of the micro-switch.
By doing this, the appearance is cleaner because you don't have to add two wires to your motor.
As for incorporating a speed controller for the motor, the jury is still out on that one.
@ Emm. Was thinking about your schematic of the DIY Motorized PingPong Slider and I think, I found a easier way to do it, I have done my own schematic, but cannot send it to you (pdf) via this account. plz tell me your email address, so I can send you the file…. 1000 Thx Tom
@Emm 1000 Thx for the schematic, would be great if it could be a bit more understandable. May be i'm too stupid to understand it…. ;-))
@Damian - Ok, i'll just have to redo it again from scratch and try to make it more understandable with different color wires (so you can follow it). Right now i'm using primarily red and black, but they jump around and interconnect it's not clear where they go even if I show it on video.
The schematic is cool but is there any chance we can get a short vid of you putting that part together? I'm new to all this and I really want to add that to my slider, without it being a fire hazard. I grabbed a 10 piece million color bluetooth led light set after I saw your vid the other day. I love that. Thanks for everything!
@TomF @Corduroy Panda @James - I just added the schematic to this article. Hopefully it makes sense. I did the best drawing I could.
Hi Emm and John,
writing from Germany, working as a DoP.
I would like to know, how exactly the electrical circuit schematic will look like and what is the exact rigging of the electronic devices and what are the exact names of it.
1000 Thx Tom
Can you display your wiring diagram? That would be awesome.
Can anyone publish the circuit schematic or a rough drawing for this circuit design? I've tried rigging it up with one DPDT relay and two mini switches without any luck.
you do realise that the parallax idea is such a simple idea? it looks like they are using an igus rail with one of the blocks on it with and arm attached to a rotating base... so easy.
@John - Thanks, mine was still a messy protoype but I plan to clean things up. Perhaps this can also be done in other ways, but the concept works.
I've done a lot of automotive electronics and we use SPDT & DPDT relays for wiring all the time. Just to make wiring easier, Id suggest using "fully insulated female spade crimp connectors" (the red one, since you are using a smaller gauge wire). Pic: https://i.imgur.com/ZF47bHO.jpg
Not sure how you have it wired, but I think you can also use two SPDT for this setup?
Here is a diagram on how the different relays are set up: https://i.imgur.com/36MVZhw.jpg
If you have a picture with the wiring, I can draft a simple wiring diagram to show others how it should be wired.
@Jeff - I guess it might work, and by varying the amount it turns perhaps you could control the center of focus. I know in the RedRock you have to be a very specific distance.
Here's just a thought, what if you mounted the whole unit onto a sturdy, motorized turntable/lazy susan that is programmed to turn a certain amount of degrees one way and then the opposite way? Might that resolve the parallax issue??
@Mike Mikkelson - Nice build, these little channel sliders are great for the small cameras. I had this slider since October and used it with the BMPCC. httpss://cheesycam.com/blackmagic-pocket-cinema-camera-w-servo-city-motorized-channel-slider-kit-a/.
I think adding the DPDT relay to your setup will really add more value to your time-lapse. You can get so much more footage going back and forth rather than letting it stop.
Really weird that you published your ActoBotics slider just a few days after I posted mine, but yours has the relays I was looking for. I'd love to get the schematics on how to make it go back and forth. Right now, mine has limit switches just to make it stop at the end of the channel. Love your blog, and love the solution for making it change motor direction.
@Sergey K - Well it's great to have that cut away shot if you're interviewing '1 person', but this Ping-Pong slider can also be used without Parabolic / Parallax movement. I can see a slider like this being setup fot BTS just moving side to side, dolly in and out, or slide up and down. (Example - "Bride doing makeup?"). It's a good tool to have dynamic movement to cut away to without a second operator.
Emm, your solution is simpler. I was affraid the motor behaviour at the edges would be unpredictable with the relay. That's why I left the manual controller in the circuit.
Guess the Kessler Parallax mechanics can be achieved with a video head, a clamp, two bearings and a metal ruler 🙂
very nice invention. it's cool to see another smart diy solution, a cheesycam specialty!
footage from the camera POV please? love to see how hard the ping & the pong are.
@marshall - At low speeds the motor on this slider has some noise, but the concept of a looping circuit can be applied to almost any slider. For this kit you can also swap to various types of motors. I have a 20 rpm motor on this.
Pretty cool. How loud is it?
As usual, a freakin' awesome Cheesycam DIY solution, with many possibilities ...