Help with pan and tilt in limited space

Hi all! I’ve been racking my head for a couple of weeks trying to think of the best solution for my project and not come up with a definitive answer so thought I would enlist all the help of you clever chaps (and chapesses)! It’s not the easiest thing to explain on a forum so bear with me! :stuck_out_tongue: I have tried to make it as clear as possible and break it up into sections but just say if anything needs elaborating!

Below I have outlined the basic project, listed what I have seen that will not work and then posted some ideas of my own. These ideas are just things that have been floating around my head for the past couple o’ weeks and have no idea if they would actually work/be practical. I would love your advice and comments on my ideas and any ideas of your own that you think may fit my project. Thanks in advance! :slight_smile:

[size=3]The project:[/size]
My project involves hiding a screen inside a container. To do so the screen has to rotate 90° and tilt 90° before then sliding into the container. This limits the size the pan and tilt system can be whilst in a certain position inside the container. The area I have to work with is denoted in the image below

The things to the side are draw slides I’m going to use to slide the screen and pan/tilt system in and out of the container. The thing at the top is the screen, rotated and tilted inside the container. The thickness of the screen above is 5mm (size of the screen plus extra for case/mount I’m yet to make). This is the maximum height the screen can be. The screen weighs 150g without a case/mount. (Depending on how weak/powerful my pan/tilt system is will depend on how lightweight/cheap I’ll try and make the case/mount)

[size=3]What won’t work:[/size]
I’ve looked at a few pan/tilt systems such as the SPT200, the SPT100 which are definitely too big and the Standard Pan & Tilt System which I’m pretty sure will be too big but unsure due to not knowing the dimensions.

There is the Micro Pan and Tilt Kit but I don’t know what the dimensions for this are and if there are micro servos powerful enough for my project.

[size=3]Question no. 1:[/size]
Would the the Micro Pan and Tilt Kit be suitable for my project?

[size=3]Idea no. 1:[/size]
I have thought about using a combination of stepper motors that would achieve the same result as a pan/tilt system but in a slightly different way, below is a crude 3D model/paint sketch to illustrate my idea. (The black line is meant to represent a mount that I would design if I went ahead with this idea) The weights and torques are from stepper motors I have just found online and can be changed (if the motors exists of course! :stuck_out_tongue:)


I have thought about using servos instead of stepper motors or a combination of the two but this is what I had already thrown together and thought it would be silly to redo the sketch for each servo/stepper motor combo I had thought of! You guys get the general idea I hope!

[size=3]Idea no. 2:[/size]
My other idea is to create my own pan/tilt mounts that combines a standard servo (chose model based off torque estimations) with the HSR-5498SG so that the standard servo mounts with the HSR-5498SG at the bottom of it rather than the side as with the other pan/tilt systems. I have created a VERY crude implementation to help explain below:

My concern with this idea is that the servos won’t be well supported and even though the screen isn’t very heavy at 150g + case/mount that the servo may break or just wobble/bounce around too much. Without actually creating the solution I wouldn’t really know how well it would turn out!

So thanks to everyone (anyone? :stuck_out_tongue:) who made it to the end of this essay of a post! I hope I have explained it well enough for you to understand. Just say if you need me to elaborate on anything or explain some of the finer details/specifications.

Thanks alot to anyone who helps out! :slight_smile:

Consider something like a bevel gear box (image below as an example):
robotshop.com/media/catalog/ … -2pk-3.jpg
You connect the two opposing bevel gears to servo motors and the third one is connected to the screen.
Note that if you rotate the motors in opposite directions, the screen will rotate, and if you rotate the motors in the same direction, the screen will tilt.
We don’t have an easy way to connect normal servos to bevel gears, but if you’re ready to use an entirely VEX-based setup:
robotshop.com/en/vex-bevel-g … t-2pk.html
robotshop.com/en/vex-robotic … r-kit.html (more gears than you need)
robotshop.com/en/vex-servo-kit.html

Thanks for the reply.

That bevel gearbox seems like a very good and compact solution.

I had noticed that the VEX servo only rotates 100° which wouldn’t be enough to rotate 90° and tilt 90°. (To rotate the screen the servos would rotate 90° in the opposite direction and to tilt they would rotate 90° in the same direction meaning one of the servos would have to rotate 180°) However, I was thinking that if you only used one servo and kept the other gear static then one 90° rotation would (I think) cause the screen to both rotate and tilt in one motion. What do you think?

Also, how would I go about calculating the required torque (kg.cm) and if the VEX servo would be upto the job? I did physics back and A Level but it’s been a while since I’ve actually used it in a practical situation.

Thanks for your help so far.

Regards

Seems about right - it just becomes a gear train.

Calculate for the worst case scenario where the weight needs to be lifted vertically (Torque = distance x force). The rotation part should not have any effect if the center of mass is located at the axis of rotation.
Perhaps something like 150g x (43.773mm/2)