# 74HC595 - shift register - how to use on node-red

**URL:** <https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568>\
**Category:** Hardware\
**Created:** [20 April 2022 22:56 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568 "2022-04-20T22:56:11Z")\
**Posts on this page:** 11\
**Page:** 1

<div class="post-metadata">

**Author:** ![ciropaes](https://avatars.discourse-cdn.com/v4/letter/c/b5e925/32.png) [@ciropaes](https://discourse.nodered.org/u/ciropaes)\
**Post date:** [20 April 2022 22:56 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/1 "2022-04-20T22:56:11Z")

</div>

could you guide me how should I work using 74HC595 on node-red installed on a raspberry pi 3?

---

<div class="post-metadata">

**Author:** ![ghayne](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/ghayne/32/39_2.png) [@ghayne](https://discourse.nodered.org/u/ghayne)\
**Post date:** [21 April 2022 11:37 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/2 "2022-04-21T11:37:37Z")

</div>

Welcome to the forum!

Can I ask what you are trying to do with a 74HC595?

---

<div class="post-metadata">

**Author:** ![ciropaes](https://avatars.discourse-cdn.com/v4/letter/c/b5e925/32.png) [@ciropaes](https://discourse.nodered.org/u/ciropaes)\
**Post date:** [22 April 2022 12:36 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/3 "2022-04-22T12:36:47Z")

</div>

Thank you for your attention!  
I need to make a board with 48 relays to work with node-red.  
But I didn't find a flow.

---

<div class="post-metadata">

**Author:** ![ghayne](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/ghayne/32/39_2.png) [@ghayne](https://discourse.nodered.org/u/ghayne)\
**Post date:** [22 April 2022 13:40 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/4 "2022-04-22T13:40:38Z")

</div>

Which board are you using?

---

<div class="post-metadata">

**Author:** ![ciropaes](https://avatars.discourse-cdn.com/v4/letter/c/b5e925/32.png) [@ciropaes](https://discourse.nodered.org/u/ciropaes)\
**Post date:** [22 April 2022 19:20 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/5 "2022-04-22T19:20:07Z")

</div>

I need to combine 3x boards similar to these with 16 channels:  
 ![s-l500](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/3/2/32f3ee1fc07e68ee7676312199d6c980bbe31593.jpeg)

I'm basing this project on pyhon. But I would like to run it with some node-red node

> **[Raspberry Pi and 74HCT595 examples - Electronic Projects](http://www.electronicprojects.net/raspberry-pi/raspberry-pi-and-74hct595-examples.php)**
>
> In this example we will connect a 74hc595 to a Raspberry Pi and then flash LEDs on and off using python and C++ Lets look at the 74hc595 The 74HC595; 74HCT595 are 8-stage serial shift registers with a storage register and 3-state outputs. The...

basically I want to automate the lighting of a shed which I will use around 40 relays.

---

<div class="post-metadata">

**Author:** ![ghayne](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/ghayne/32/39_2.png) [@ghayne](https://discourse.nodered.org/u/ghayne)\
**Post date:** [22 April 2022 19:35 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/6 "2022-04-22T19:35:19Z")

</div>

> [@ciropaes](#):
>
> basically I want to automate the lighting of a shed which I will use around 40 relays.

So you have a shed with 40 lights?

---

<div class="post-metadata">

**Author:** ![Sean-McG](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/sean-mcg/32/54677_2.png) [@Sean-McG](https://discourse.nodered.org/u/Sean-McG)\
**Post date:** [23 April 2022 07:38 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/7 "2022-04-23T07:38:27Z")

</div>

You may have more luck with the MCP23017 chips, there are several nodes that work with them such as this

> **[@pizzaprogram/mcp-pcf-aio](https://flows.nodered.org/node/@pizzaprogram/mcp-pcf-aio)**
>
> Node-Red node for multiple MCP23017 chips (each 16 input or output) + PCF8574(A) (8 I/O). The I2C Bus number can be specified too.

---

<div class="post-metadata">

**Author:** ![Sean-McG](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/sean-mcg/32/54677_2.png) [@Sean-McG](https://discourse.nodered.org/u/Sean-McG)\
**Post date:** [23 April 2022 13:06 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/8 "2022-04-23T13:06:34Z")

</div>

Must be a very large shed or a disco 🤩

---

<div class="post-metadata">

**Author:** ![ciropaes](https://avatars.discourse-cdn.com/v4/letter/c/b5e925/32.png) [@ciropaes](https://discourse.nodered.org/u/ciropaes)\
**Post date:** [27 April 2022 13:13 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/9 "2022-04-27T13:13:01Z")

</div>

thanks for the tip.  
I will buy some to test. So far I have had success with CI PCF8574A using python commands.  
I created an EXEC node and it was easy.

> **[GitHub - oweidner/i2crelay: A Python library and command line tool to control...](https://github.com/oweidner/i2crelay)**
>
> A Python library and command line tool to control PCF8574 I2C relay boards - GitHub - oweidner/i2crelay: A Python library and command line tool to control PCF8574 I2C relay boards

---

<div class="post-metadata">

**Author:** ![Sean-McG](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/sean-mcg/32/54677_2.png) [@Sean-McG](https://discourse.nodered.org/u/Sean-McG)\
**Post date:** [27 April 2022 15:34 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/10 "2022-04-27T15:34:09Z")

</div>

With MCP23017 you can control from within NR at least 😀

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [26 June 2022 15:34 UTC](https://discourse.nodered.org/t/74hc595-shift-register-how-to-use-on-node-red/61568/11 "2022-06-26T15:34:45Z")

</div>

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.