# Crelay and Sainsmart USB relays

**URL:** <https://discourse.nodered.org/t/crelay-and-sainsmart-usb-relays/30430>\
**Category:** General\
**Created:** [21 July 2020 00:49 UTC](https://discourse.nodered.org/t/crelay-and-sainsmart-usb-relays/30430 "2020-07-21T00:49:07Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![VA3CW](https://avatars.discourse-cdn.com/v4/letter/v/8e7dd6/32.png) [@VA3CW](https://discourse.nodered.org/u/VA3CW)\
**Post date:** [21 July 2020 00:49 UTC](https://discourse.nodered.org/t/crelay-and-sainsmart-usb-relays/30430/1 "2020-07-21T00:49:07Z")

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Hi all!

I've got Node-RED installed on a RPi4 and am using it to control a Sainsmart USB (FTDI) relay board. So far things seem to work with **crelay** however I'm suspicious that my approach is less than an efficient use of processor time...

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/2/c/2c52088a790bc0ac75b03a2a002db1dd0a8b9bf3.png)

There is an http daemon for crelay but I've avoided using it and am putzing around with MQTT to affect the same functionality. Ideally I'd like to be able to get a byte-wide post/get rather than relying single cmds.

Would be grateful for any feedback on using these boards and crelay.

Thanks,  
Andy

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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:** [19 September 2020 00:49 UTC](https://discourse.nodered.org/t/crelay-and-sainsmart-usb-relays/30430/2 "2020-09-19T00:49:07Z")

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Closed on 19 September 2020 00:49 UTC

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