# Easy way to send 4-bit string to 4 separate GPIO out pins

**URL:** <https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379>\
**Category:** General\
**Created:** [2 December 2023 15:19 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379 "2023-12-02T15:19:32Z")\
**Posts on this page:** 14\
**Page:** 1

<div class="post-metadata">

**Author:** ![daxliniere](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/daxliniere/32/42187_2.png) [@daxliniere](https://discourse.nodered.org/u/daxliniere)\
**Post date:** [2 December 2023 15:19 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/1 "2023-12-02T15:19:32Z")

</div>

I have one of the old Energenie transmitter boards (which is not supported by contrib-energenie-ener314rt). The board has 6 inputs: protocol OOK/FSK, modulator enable and 4 data pins for setting a 4-bit sata string. There's a Python example script that works this way: set state of 4 GPIO pins, set modulator to high, pause, set modulator to low.

There are 10 combinations of the 4-bit string that it will accept. (socket #1 on, socket #1 off, #2 on, #2 off, ...all on, all off.)

I'm looking for an easy way to send each of those 4-bit strings.

I found a flow which allows you to send multi-line exec node commands and set it up for that purpose, but I think it's not working correctly (or the sockets have a problem? Hence the debugging), so I was trying to find a way to see the state of the 4 GPIO out pins.

If anyone knows of a better way to do this, where a code can be transmitted when triggered via button or a timer in another part of the flow, I'd be grateful to hear about it.

All the best,  
Dax.

```auto
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    },
    {
        "id": "7f87ef523d955b62",
        "type": "template",
        "z": "e7bc54457b5634db",
        "name": "Shell Script",
        "field": "payload",
        "fieldType": "msg",
        "format": "handlebars",
        "syntax": "mustache",
        "template": "#! /bin/sh\n\nraspi-gpio set 24 dl",
        "x": 290,
        "y": 140,
        "wires": [
            [
                "5b242947.2d4ac8"
            ]
        ]
    },
    {
        "id": "4275755d2bb2b92d",
        "type": "rpi-gpio out",
        "z": "e7bc54457b5634db",
        "d": true,
        "name": "Mode select (low=OOK mode)",
        "pin": "24",
        "set": true,
        "level": "0",
        "freq": "",
        "out": "out",
        "bcm": true,
        "x": 710,
        "y": 560,
        "wires": []
    },
    {
        "id": "02a1c830607dc6bc",
        "type": "rpi-gpio in",
        "z": "e7bc54457b5634db",
        "name": "GPIO 27",
        "pin": "27",
        "intype": "tri",
        "debounce": "25",
        "read": true,
        "bcm": true,
        "x": 920,
        "y": 260,
        "wires": [
            [
                "68edf16c66b98012"
            ]
        ]
    },
    {
        "id": "ced24b84793e7187",
        "type": "rpi-gpio in",
        "z": "e7bc54457b5634db",
        "name": "GPIO23",
        "pin": "23",
        "intype": "tri",
        "debounce": "25",
        "read": true,
        "bcm": true,
        "x": 920,
        "y": 320,
        "wires": [
            [
                "5a66232ebdaab619"
            ]
        ]
    },
    {
        "id": "b3d901a3379f899c",
        "type": "rpi-gpio in",
        "z": "e7bc54457b5634db",
        "name": "GPIO22",
        "pin": "22",
        "intype": "tri",
        "debounce": "25",
        "read": true,
        "bcm": true,
        "x": 920,
        "y": 380,
        "wires": [
            [
                "743fba18cff09729"
            ]
        ]
    },
    {
        "id": "fed780bb4417682e",
        "type": "rpi-gpio in",
        "z": "e7bc54457b5634db",
        "name": "GPIO17",
        "pin": "17",
        "intype": "tri",
        "debounce": "25",
        "read": true,
        "bcm": true,
        "x": 920,
        "y": 440,
        "wires": [
            [
                "1fa7bcd106266a0d"
            ]
        ]
    },
    {
        "id": "68edf16c66b98012",
        "type": "debug",
        "z": "e7bc54457b5634db",
        "name": "debug 1",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": true,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "payload",
        "statusType": "auto",
        "x": 1060,
        "y": 260,
        "wires": []
    },
    {
        "id": "5a66232ebdaab619",
        "type": "debug",
        "z": "e7bc54457b5634db",
        "name": "debug 2",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": true,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "payload",
        "statusType": "auto",
        "x": 1060,
        "y": 320,
        "wires": []
    },
    {
        "id": "743fba18cff09729",
        "type": "debug",
        "z": "e7bc54457b5634db",
        "name": "debug 3",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": true,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "payload",
        "statusType": "auto",
        "x": 1060,
        "y": 380,
        "wires": []
    },
    {
        "id": "1fa7bcd106266a0d",
        "type": "debug",
        "z": "e7bc54457b5634db",
        "name": "debug 4",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": true,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "payload",
        "statusType": "auto",
        "x": 1060,
        "y": 440,
        "wires": []
    }
]

```

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [2 December 2023 15:31 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/2 "2023-12-02T15:31:41Z")

</div>

> [@daxliniere](#):
>
> I was trying to find a way to see the state of the 4 GPIO out pins.

As I said in your earlier thread, the GPIO Out node shows the current status underneath it.

---

<div class="post-metadata">

**Author:** ![daxliniere](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/daxliniere/32/42187_2.png) [@daxliniere](https://discourse.nodered.org/u/daxliniere)\
**Post date:** [2 December 2023 15:49 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/3 "2023-12-02T15:49:38Z")

</div>

Yes, but I don't know of an wasy way to send a 4-bit string to 4 separate GPIO nodes.

If only our GPIO-out node would accept topic, then you could send **msg.topic=GPIO22 msg.payload=high**

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [2 December 2023 16:00 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/4 "2023-12-02T16:00:43Z")

</div>

Do you already have this 4 bit string? If so feed it into a debug mode and show us what it looks like. The term 4 bit string is ambiguous.

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [2 December 2023 16:16 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/5 "2023-12-02T16:16:00Z")

</div>

If you do not already have it then an array would probably be the easiest way to handle it, then you can easily use a Change node in front of each GPIO to move the relevant bits into the payload.

---

<div class="post-metadata">

**Author:** ![daxliniere](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/daxliniere/32/42187_2.png) [@daxliniere](https://discourse.nodered.org/u/daxliniere)\
**Post date:** [2 December 2023 17:01 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/6 "2023-12-02T17:01:37Z")

</div>

D3 is GPIO27  
D2 is GPIO23  
D1 is GPIO22  
D0 is GPIO17

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/9/0/909c127ba5746974abf84207c03d642538f81044.png)

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [2 December 2023 17:23 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/7 "2023-12-02T17:23:27Z")

</div>

Does something like this should do what you want? I have just coded up a few of the inputs. Note that in the array they are order D0 first.

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/c/4/c4039bb140da87c4a815c7d1e44d43df7287ff9d.png)

```auto
[{"id":"43d30d5f05507eed","type":"inject","z":"bdd7be38.d3b55","name":"All On","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"[1,1,0,1]","payloadType":"json","x":150,"y":3280,"wires":[["8cae4b4dc99e2022"]]},{"id":"48d6aa97c1e555c2","type":"inject","z":"bdd7be38.d3b55","name":"Socket 1 on","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"[1,1,1,1]","payloadType":"json","x":170,"y":3320,"wires":[["8cae4b4dc99e2022"]]},{"id":"7f2c583a81dda415","type":"change","z":"bdd7be38.d3b55","name":"D0","rules":[{"t":"set","p":"payload","pt":"msg","to":"payload[0]","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":410,"y":3220,"wires":[["3df5efcbf9215046"]]},{"id":"ebbf54bf7bf74a56","type":"change","z":"bdd7be38.d3b55","name":"D1","rules":[{"t":"set","p":"payload","pt":"msg","to":"payload[1]","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":410,"y":3300,"wires":[["aa3b6e06c1ca5356"]]},{"id":"f1687ff5b8d1a00f","type":"change","z":"bdd7be38.d3b55","name":"D2","rules":[{"t":"set","p":"payload","pt":"msg","to":"payload[2]","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":410,"y":3380,"wires":[["8c459e0d1b711d04"]]},{"id":"eb39f2dc310ecacd","type":"change","z":"bdd7be38.d3b55","name":"D3","rules":[{"t":"set","p":"payload","pt":"msg","to":"payload[3]","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":410,"y":3460,"wires":[["0dd6dc86b522d6fc"]]},{"id":"a787b702163e4cea","type":"inject","z":"bdd7be38.d3b55","name":"Socket 2 on","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"[0,1,1,1]","payloadType":"json","x":170,"y":3360,"wires":[["8cae4b4dc99e2022"]]},{"id":"3df5efcbf9215046","type":"debug","z":"bdd7be38.d3b55","name":"D0","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":550,"y":3220,"wires":[]},{"id":"aa3b6e06c1ca5356","type":"debug","z":"bdd7be38.d3b55","name":"D1","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":550,"y":3300,"wires":[]},{"id":"8c459e0d1b711d04","type":"debug","z":"bdd7be38.d3b55","name":"D2","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":550,"y":3380,"wires":[]},{"id":"0dd6dc86b522d6fc","type":"debug","z":"bdd7be38.d3b55","name":"D3","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":550,"y":3460,"wires":[]},{"id":"a41e483be1638db0","type":"comment","z":"bdd7be38.d3b55","name":"The GPIO nodes go alongside these","info":"","x":640,"y":3180,"wires":[]},{"id":"8cae4b4dc99e2022","type":"junction","z":"bdd7be38.d3b55","x":300,"y":3320,"wires":[["7f2c583a81dda415","ebbf54bf7bf74a56","f1687ff5b8d1a00f","eb39f2dc310ecacd"]]}]

```

---

<div class="post-metadata">

**Author:** ![daxliniere](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/daxliniere/32/42187_2.png) [@daxliniere](https://discourse.nodered.org/u/daxliniere)\
**Post date:** [2 December 2023 17:49 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/8 "2023-12-02T17:49:17Z")

</div>

Ahh! Treat it as an array! I also didn't know about the msg.payload[_index number_] trick. That is really cool.

I swear, every time I pose a question on this forum, I learn a new technique that goes beyond the usefulness of just that particular situation. Thank you so much, Colin, I really appreciate it! 😊

I'll re-set the index order, add the GPIOs and test this flow out.

Have a great evening.

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [2 December 2023 18:19 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/9 "2023-12-02T18:19:11Z")

</div>

> [@daxliniere](#):
>
> I'll re-set the index orde

D0 should be element 0 of the array, otherwise you will get confused, or I would anyway.

---

<div class="post-metadata">

**Author:** ![daxliniere](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/daxliniere/32/42187_2.png) [@daxliniere](https://discourse.nodered.org/u/daxliniere)\
**Post date:** [2 December 2023 19:13 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/10 "2023-12-02T19:13:36Z")

</div>

Thanks so much, Colin, I've tested it and all sockets are now working as expected. Now I can turn my home-made nuclear reactor on and off remotely! _Just kidding!_ 😆

D3 is the MSB, so makes sense to be the first and that's also how it is in the Energenie documentation.

All the best!  
Dax.

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [2 December 2023 21:36 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/11 "2023-12-02T21:36:14Z")

</div>

> [@daxliniere](#):
>
> D3 is the MSB, so makes sense to be the first

Suppose they updated the product and added D5. Then you would have to rework your flow. With D0 as element 0 in the array you could just add the extra bit.

---

<div class="post-metadata">

**Author:** ![daxliniere](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/daxliniere/32/42187_2.png) [@daxliniere](https://discourse.nodered.org/u/daxliniere)\
**Post date:** [2 December 2023 23:53 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/12 "2023-12-02T23:53:05Z")

</div>

They already have upgraded the product (ENER314-RT) and there's a whole contrib library for it. 🙂

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [3 December 2023 10:03 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/13 "2023-12-03T10:03:14Z")

</div>

I was attempting to point out that using element 0 as D0 is a better way for the general case. It is always a good idea to think about the general case when coding, so that the code can either be extended more easily or reused the next time you have some similar problems.

---

<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:** [17 December 2023 10:03 UTC](https://discourse.nodered.org/t/easy-way-to-send-4-bit-string-to-4-separate-gpio-out-pins/83379/14 "2023-12-17T10:03:44Z")

</div>

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