User avatar
Smntk
Posts: 11
Joined: Sun Mar 31, 2019 11:11 am

Projector power controlled by Raspberry

Wed May 08, 2019 6:12 pm

Hi!
I have bought some Cube Rif6 picoprojectors for my project, which includes a Raspberry Pi for sending the moving image via HDMI cable (in this case).
As the Raspberry Pi has 5V GPIOs (it is what the picoprojector needs), I will power it from that pin.
The picoprojector has a small push button for switching it on. You have to press and hold it for about two seconds to turn it on. The same button lets you switch it off (in this case, you don't have to hold it for two seconds, you simply push and that's it).
The question is: I want to switch the picoprojector on from the Raspberry Pi.
I have opened it and I can see a small switch push button (i think it is a momentary push button).
Front.JPG
Front.JPG (182.7 KiB) Viewed 503 times
I think is something like this, but dimensions are 2.2x4.5x3.5 mm aprox: https://es.aliexpress.com/item/OOTDTY-1 ... 72894.html
I have read some post talking about using using a "physical" system, like a little solenoid motor that pushes the projector button or a servo motor. But my initial idea was to desolder the switch and connect two cables for using a NPN transistor which was connected to the GPIO pins for control the on/off function. Now that I can see that it is a very tiny device, I think that it will be very complicated.
3_4.JPG
3_4.JPG (230.77 KiB) Viewed 503 times
I think is a 4 pin switch as you see in the images, but I'm doubting if it could be a 2 pin switch push button. Here, you can see the back side of the switch reflected in a tool:
Back.JPG
Back.JPG (226.88 KiB) Viewed 503 times
(it seems that I can't attach more pictures, i'll try to show a view of the down side in another post)

I thought that perhaps I can cut with a cutter the two little pieces of plastic that hold the front metal tap (they are beside the black push button as you can see in the front view). Perhaps then I can take out the little metal cover that is in the front side and access to the 2 contacts. May it be easier for soldering 2 cables from there?
I thought in another solution: if that doesn't work, perhaps I can unsolder the button and connect the contacts with tin solder. Then, I could turn on and off the projector simply controlling the 5V power supply, but I have done some tests and the menu doesn't appear if I keep the button pressed, as it normally do when I push it and hold for 2 seconds, as a normal on process require. I have tested it with a HDMI/MHL smartphone connection and I can see the movie that is been played in the smartphone, but suddenly it turned crazy and began to close the video and open the apps in a randow sequence, like the projector were returning orders to it (????????????)
I don't know what to do. I am afraid of unsolder the original switch and break the projector, but perhaps it is a risk that I have to take.

What do you think?
Thank in advance, you're all great!
Last edited by Smntk on Thu May 09, 2019 4:47 pm, edited 2 times in total.

User avatar
Smntk
Posts: 11
Joined: Sun Mar 31, 2019 11:11 am

Re: Projector power controlled by Raspberry

Thu May 09, 2019 4:45 pm

This is the downside image:
Downside.JPG
Downside.JPG (215.07 KiB) Viewed 502 times
Here is another image of the whole picoprojector. The Cube Rif6 is a tiny device, its dimensions are 5x5x5 mm or 2x2x2 inches.
Whole.jpg
Whole.jpg (145.8 KiB) Viewed 502 times
Thanks!

PhatFil
Posts: 1189
Joined: Thu Apr 13, 2017 3:55 pm
Location: Oxford UK

Re: Projector power controlled by Raspberry

Thu May 09, 2019 4:56 pm

hi there,

#1 pi gpio pins supply 3.3v when set High. but there is a 5v power pin on the gpio header.

the 2 x solderpads visible and accessible each side of the rear of the micro switch are probably each side of the open switch. Confirm this with no power connected to the device using a multimeter set to test continuity (beeps when probes touch) if touching each pad with a probe results in no beep but you get a beep with the button pushed the above is a correct assumption.

and you could impliment a solution similar to those discussed in this recent post if you can solder to the switch connections. viewtopic.php?f=91&t=239710

Brandon92
Posts: 770
Joined: Wed Jul 25, 2018 9:29 pm
Location: Netherlands

Re: Projector power controlled by Raspberry

Thu May 09, 2019 5:55 pm

What I would do in you situation.
Like PhatFil recommended you need to measure it is indeed the switch contact, but I'm almost sure the back connection are the right one. Then solder a thin wire on that pad, it could be with the switch on it. So you can also turn in on/off with the original switch. Then find a nice exit for the wires and make sure you can not pull on it, otherwise you could damage the pad.I would use a optocoupler for the switching. Then you don't introduce noise to both systems and make you life a lot easier.

User avatar
Smntk
Posts: 11
Joined: Sun Mar 31, 2019 11:11 am

Re: Projector power controlled by Raspberry

Thu May 23, 2019 8:38 am

Hi all!
I was very afraid because for following the advices from PhatFil and Brandon92 to test the solderpads I had to take out the cover that was in the opposite side to the switch side and try to push the board to take it out. I was very afraid that the optical system could move and lose the projector.
Because I have some more projectors, I decided to do it and I took off the cover and I saw there were 6 little screws (as in the other side).
backcover.jpg
backcover.jpg (247.73 KiB) Viewed 386 times
I took them off and took the cover off and gently pushed the whole system (except the battery, that was disconnected easily because of it has a little and useful connector)
batteryconnector.jpg
batteryconnector.jpg (190.88 KiB) Viewed 386 times
I saw that the data cable for the image signal (I think that it is the brown flat cable) was very close to the switch. I had to solder, so it was dangerous to have that cable close to the soldering iron. I tried to take the brown cable off, but the conection was strange. I thought that I saw two soldering points that I thought that were for not letting to disconnect the brown cable (perhaps you can see one of them in the picture).
opened.jpg
opened.jpg (234.1 KiB) Viewed 386 times
Probably, I am wrong but I didn't want to take risks and I decided to solder with the cable connected.

User avatar
Smntk
Posts: 11
Joined: Sun Mar 31, 2019 11:11 am

Re: Projector power controlled by Raspberry

Thu May 23, 2019 8:51 am

(I forgot to talk about one step: before I soldered, I used the multimeter as PhatFil said and I realized that the two soldering pads where the ones that I have to use. Thanks, PhatFil!!!!)
-----------------------------------------------------------------------------------------------------------------------------
So, I made the hardest soldering task that I have made in my life. I put the smallest tip in the soldering iron and begin to solder with a led headband magnifier. Finally, I could do it!!!!
:D
soldered.jpg
soldered.jpg (196.33 KiB) Viewed 377 times
Today I'm superhappy. I have followed the wise advices from PhatFil and Brandon92 (thanks a lot, guys!!!!) and I tested the projector and everything works perfectly! I can even use the original switch as Brandon92 said!!!!
finished.jpg
finished.jpg (167.34 KiB) Viewed 377 times
Now, I'm going downstairs to buy an optocoupler. I hope that the guy from the electronic shop has one, otherwise I have to buy one in internet and I will have to wait some days till I receive it.
Thanks a lot. I'll post new achievements!!!!!! :)

Brandon92
Posts: 770
Joined: Wed Jul 25, 2018 9:29 pm
Location: Netherlands

Re: Projector power controlled by Raspberry

Thu May 23, 2019 9:03 am

Good job :)
As another advice, I would take a closer look to the PCB. So follow the traces from the switch. If you are lucky one of the traces goes to for example R215 and that makes the soldering a lot easier for you. And maybe the other connection from the switch goes to the ground of the system and you can find another easy to solder spot.

User avatar
Smntk
Posts: 11
Joined: Sun Mar 31, 2019 11:11 am

Re: Projector power controlled by Raspberry

Sun May 26, 2019 11:15 am

Optocoupler working fine with a simple Processing sketch!!!!
Really happy!!!
OptocouplerWorking.jpg
OptocouplerWorking.jpg (165.34 KiB) Viewed 310 times

User avatar
Smntk
Posts: 11
Joined: Sun Mar 31, 2019 11:11 am

Re: Projector power controlled by Raspberry

Mon May 27, 2019 9:49 am

Soldered in a tiny board and working perfectly in a Jetson Nano. :D
I had to quit about using the Raspbery Pi due to the complexity of implement in it an on/off button for switching the whole system on and off. It's easier in the Jetson Nano, but I'm having lots of problems with Processing software due to the need of Java 8 for running Processing sketches. Now I'm using Zulu OpenJDK 8 version and I can't run the sketches if they are programmed for using them with the OpenGL renderer (then appears a Java error). If I use the default renderer, which is slower, there is no problem.
In Raspberry Pi those tasks were easier due to the Raspberry Pi Processing version (https://pi.processing.org/).
OctocouplerBoard.jpg
OctocouplerBoard.jpg (170.83 KiB) Viewed 276 times

Return to “Other projects”