I'm planning to make an automatic sliding tray for a UST projector.
What I'd like to achieve is:
Projector powered on state is detected via it's usb port, the tray moves "home" then forward a certain distance. When the projector is turned off the tray moves back to "home" position.
I'm a novice at this but have been doing some research and came up with a parts list and an initial sketch, I'm sure it has quite a few things wrong with it. I'd appreciate any advice and help with this.
I haven't ordered any of the parts yet but, these are what i've selected:
[USB C Breakout
Cosmo K1010 Optocoupler
RS PRO 220Ω Carbon Film Resistor 0.25W ±5%
Seeeduinio XIAO Development Board, SAMD21
TMC2209 V1.3
NEMA 17 Stepper Motor
Adafruit USB Type C Power Delivery Dummy Breakout - I2C or Fixed - HUSB238
LM3671 3.3V Buck Converter Breakout - 3.3V Output 600mA Max
SparkFun BabyBuck Regulator Breakout - 5V (AP63357)
100uF 16V Electrolytic Capacitors - Pack of 10
Micro Switch w/Lever - 2 Terminal
Power from a usb power supply, Ugreen 35W GaN charger. HUSB238 set to pull 9V 3A from it.
Is this tray already part of a UST projector? Do all UST projectors have the same tray or will your project only work with your projector?
What powers and supports the tray so it can move?
How will the tray be moved if the power is already off?
Where would it go?
I didn't realise there was a thing as bypass caps, I've just put some regular capacitors in the circuit. Is 3 too many?
Other than that, does the circuit look functional? I don't have any of the parts to test.
Hoping to get all I need at once.
No, I'll make the tray with some MDF.
I intend to power the stepper motor with the same USB power supply which will always be on.
The projector has a usb port, which I'm hoping to link to the circuit with an optocoupler, so that projectors power state can be detected when the usb port on the projector is powered on and off along with the projector.
Ok, but the tray will have to be supported by something that allows the sliding. The stepper will need some mechanism to cause the tray movement in two directions. How will the stepper know the position of the tray, open or closed?
I intend to use two pieces of wood, top and bottom, joined by undermount drawer sliders.
The stepper motor to be attached to the top wood piece by a mounting point on a lead screw.
I intend to put a limit switch at the "home" position, then have the motor go "home" first then out to desired position on opening, upon closing it should just go to "home" position.
Instead of doing all of this at the component level, I'd normally use as many modules as I can especially for a project like this that's mostly a solved problem.
Convenient sensors to detect home and end. Hall sensor, optical, or limit switch
Controller: literally any arduino will be sufficient
H-bridge motor driver: buy off the shelf
Linear actuator
AC/DC power supply: buy off the shelf
The only thing that's a bit unusual is sensing that the projector is on via the USB port, but there's nothing in this project that screams "design a custom circuit" at me.
You are designing and developing a new circuit for a specific and (relatively) unique purpose. It's an iterative process. You will make mistakes, learn from them, modify the design and repeat. Accept that.
I'm a novice at this and may have used the wrong terminology when I asked for help with designing a circuit. Like you've said I intend to use those parts:
Limit switch
Seeedstudio Xiao samd21
TMC2209 driver
USB power supply.
What I meant was I need help in wiring it up, I'm not sure what I've layed out would work or cause any damage.
I'll look into linear actuators, if it'll be easier to work with and cheaper.
OK, I may have been a bit hasty. I read "circuit design" and saw a schematic with capacitors and it appeared that you were attempting to design your own power supply.
As far as the layout, it looks OK at a glance. Standard method would be to add one part at a time, instead of wiring it all together and hoping it works. Connect power and switches to arduino, make sure it works. Add motor, drive it forward and back, etc.
I do understand I'll be doing some trial and error with this, I've allowed myself some months on this project.
I'm not confident in my wiring of the components and don't want to burn the house down.
Wanting some feedback on the wiring, to any obvious mistakes I've made, anything I can remove or add.
30cm for current projector and cabinet.
I've found the only one undermount slider and that extends to 90cm so some headroom there but ultimately will be limited by the length of the screw which in turn is limited by the depth of the shelf.
But at the moment I'm not concerned about that, I should have plenty of distance for future projectors since they seem to be getting shorter throws.
One part I'm definitely unsure about, is the power going to the Xiao from the optocoupler, I've just stuck a 220ohm resister in there going by what I've seen. Really unsure about if that's the right way to go about it.
This is for detecting if the USB socket is powered? I don't think you need a resistor for that. Just connect the opto-coupler's output between the Xiao input pin and ground and set the mode to INPUT_PULLUP.
Oh, wait. Did you mean the power going from the projector's USB socket to the optocoupler? You will need a resistor for that. The value won't be critical, anything between around 220R to 2K2 might be ok. I would guess something on the lower end of that range. You're not trying to minimise power consumption, after all. Who cares if it uses a few unnecessary milliamps, compared to the consumption of a UST projector!
Out of personal interest, what make/model of projector? Mine is an Optoma Cinemax P2.
