# Control a Benq video beamer with serial port

**URL:** <https://discourse.nodered.org/t/control-a-benq-video-beamer-with-serial-port/15009>\
**Category:** General\
**Created:** [1 September 2019 18:52 UTC](https://discourse.nodered.org/t/control-a-benq-video-beamer-with-serial-port/15009 "2019-09-01T18:52:20Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![RogierQ](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rogierq/32/3211_2.png) [@RogierQ](https://discourse.nodered.org/u/RogierQ)\
**Post date:** [1 September 2019 18:52 UTC](https://discourse.nodered.org/t/control-a-benq-video-beamer-with-serial-port/15009/1 "2019-09-01T18:52:20Z")

</div>

Hi!

Trying hard to control my video beamer over rs232 serial port  
But without any succes, even no error messages ☹

For example what i try to do is this: \*pow=off#  
So i put this in an inject node that is connected to the serial port with the right baud settings.  
Any times on how to do this?

Thanks!!!!

more info

> **[lh770-rs232-control-guide-0-windows7-windows8-winxp.pdf](https://business-display.benq.com/content/dam/bb/en/product/projector/corporate/lh770/quick-start-guide/lh770-rs232-control-guide-0-windows7-windows8-winxp.pdf)**
>
> 950.12 KB

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [1 September 2019 19:09 UTC](https://discourse.nodered.org/t/control-a-benq-video-beamer-with-serial-port/15009/2 "2019-09-01T19:09:08Z")

</div>

Looking at the documentation:

```auto
<CR>*pow=off#<CR>

```

it needs a carriage return before and after, did you try:

```auto
\r*pow=off#\r

```

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<div class="post-metadata">

**Author:** ![RogierQ](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rogierq/32/3211_2.png) [@RogierQ](https://discourse.nodered.org/u/RogierQ)\
**Post date:** [1 September 2019 19:23 UTC](https://discourse.nodered.org/t/control-a-benq-video-beamer-with-serial-port/15009/3 "2019-09-01T19:23:32Z")

</div>

thanks, i will try it directly!

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<div class="post-metadata">

**Author:** ![RogierQ](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rogierq/32/3211_2.png) [@RogierQ](https://discourse.nodered.org/u/RogierQ)\
**Post date:** [1 September 2019 19:27 UTC](https://discourse.nodered.org/t/control-a-benq-video-beamer-with-serial-port/15009/4 "2019-09-01T19:27:29Z")

</div>

Nope no result.  
What i do is this.

```auto
[{"id":"a4b09b4c.8f0318","type":"serial request","z":"9f605b7b.790358","name":"","serial":"cc764c90.f1d708","x":510,"y":160,"wires":[["b804cd5c.b5ac5"]]},{"id":"b804cd5c.b5ac5","type":"debug","z":"9f605b7b.790358","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":670,"y":160,"wires":[]},{"id":"4ecf9592.0a0b44","type":"inject","z":"9f605b7b.790358","name":"","topic":"","payload":"\\r*pow=off#\\r","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":250,"y":160,"wires":[["a4b09b4c.8f0318"]]},{"id":"cc764c90.f1d708","type":"serial-port","z":"","serialport":"/dev/ttyUSB0","serialbaud":"115200","databits":"8","parity":"none","stopbits":"1","waitfor":"","newline":"\\n","bin":"false","out":"char","addchar":"","responsetimeout":"10000"}]

```

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<div class="post-metadata">

**Author:** ![edje11](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/edje11/32/572_2.png) [@edje11](https://discourse.nodered.org/u/edje11)\
**Post date:** [1 September 2019 19:44 UTC](https://discourse.nodered.org/t/control-a-benq-video-beamer-with-serial-port/15009/5 "2019-09-01T19:44:29Z")

</div>

Did you checked the baudrate in the beamer menu?  
Did you used the cross cable as described on page 4?

The beamer should at least echo something, even if it's a unknown command etc.

On what hardware do you have NR running?

---

<div class="post-metadata">

**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [1 September 2019 19:52 UTC](https://discourse.nodered.org/t/control-a-benq-video-beamer-with-serial-port/15009/6 "2019-09-01T19:52:22Z")

</div>

You probably need to just add \r to the serial port control config

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/4/40584e8a7ce4f74dbbd88480a93669cb8699483d.png)

(plus make sure you have latest serial port node as there was a bug in it until yesterday.)

Adding \r in an inject node will just add the character \ followed by r  
An alternative is to add a function node containing

```auto
msg.payload = msg.payload + "\r";
return msg;

```