# Communication between smartphones and a projector. Remote Control Phone

**URL:** <https://discourse.nodered.org/t/communication-between-smartphones-and-a-projector-remote-control-phone/45488>\
**Category:** General\
**Created:** [11 May 2021 11:40 UTC](https://discourse.nodered.org/t/communication-between-smartphones-and-a-projector-remote-control-phone/45488 "2021-05-11T11:40:24Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![tom123](https://avatars.discourse-cdn.com/v4/letter/t/d78d45/32.png) [@tom123](https://discourse.nodered.org/u/tom123)\
**Post date:** [11 May 2021 11:40 UTC](https://discourse.nodered.org/t/communication-between-smartphones-and-a-projector-remote-control-phone/45488/1 "2021-05-11T11:40:24Z")

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Hi guys,  
I want to make an Mobile app which can connnect to the Smart Xiaomi Projector (Android). With a smartphone, the teacher can control the powerpoint file which is saved locally in the projector. It's like the Mi Home app, make a phone become a remote control.  
I'm new with BLE and NodeRed, as I know, I need to define :

- Connection between phones and a projector (BLE).
- Protocol to transfer/receive commands from a phone to the projector.
- Apply these commands to powerpoint files in the projector.

My phone is connected to the projecteur via Bluetooth, next step is looking for a protocol. Do you know what protocol that i need to use in this case? And then how to apply commands received to powerpoint files in the projector so that I can control it?

Thanks a lot!  
Tom

![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/0/c/0cfb1a2679226b0106ba1e18c1da8e974faa6a4f.png)

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**Author:** ![janvda](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/janvda/32/234_2.png) [@janvda](https://discourse.nodered.org/u/janvda)\
**Post date:** [11 May 2021 12:06 UTC](https://discourse.nodered.org/t/communication-between-smartphones-and-a-projector-remote-control-phone/45488/2 "2021-05-11T12:06:19Z")

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It all depends on your projector device and what APIs it supports.  
So you need to share some more details about your actual Smart Projector Xiaomi.

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**Author:** ![tom123](https://avatars.discourse-cdn.com/v4/letter/t/d78d45/32.png) [@tom123](https://discourse.nodered.org/u/tom123)\
**Post date:** [11 May 2021 12:56 UTC](https://discourse.nodered.org/t/communication-between-smartphones-and-a-projector-remote-control-phone/45488/3 "2021-05-11T12:56:00Z")

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It is a Mi Laser Projector 150.

- You can find its user manual here: [https://i01.appmifile.com/webfile/globalimg/Global\_UG/Mi\_Ecosystem/Mi\_Laser\_Projector\_150/en\_V1.pdf](https://i01.appmifile.com/webfile/globalimg/Global_UG/Mi_Ecosystem/Mi_Laser_Projector_150/en_V1.pdf)
- its datasheet: [Mi Laser Projector 4K 150 | Xiaomi Quality | 4K](https://www.powerplanetonline.com/en/xiaomi-mi-4k-laser-projector-150)

I don't understand why do we need API for this communication between them, this communication is via Bluetooth? Please tell me if you need any more details.

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**Author:** ![janvda](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/janvda/32/234_2.png) [@janvda](https://discourse.nodered.org/u/janvda)\
**Post date:** [11 May 2021 13:15 UTC](https://discourse.nodered.org/t/communication-between-smartphones-and-a-projector-remote-control-phone/45488/4 "2021-05-11T13:15:48Z")

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Sorry, I see your need now.  
So you don't want to use the bluetooth remote control but a kind of app on a smartphone.

As the Xiaomi projector seems to run android, have you tried using some android (tv) remote control app (e.g _Android TV Remote Control)_ ?

I guess the other approach is to try to reverse engineer the bluetooth protocol which seems an extremely difficult task to me.

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [10 July 2021 13:15 UTC](https://discourse.nodered.org/t/communication-between-smartphones-and-a-projector-remote-control-phone/45488/5 "2021-07-10T13:15:52Z")

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