# Water level in TANK
**URL:** https://discourse.nodered.org/t/water-level-in-tank/73947
**Category:** General
**Created:** [20 January 2023 09:52 UTC](https://discourse.nodered.org/t/water-level-in-tank/73947 "2023-01-20T09:52:10Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@pierrot](https://discourse.nodered.org/u/pierrot)
#### Post date: [20 January 2023 09:52 UTC](https://discourse.nodered.org/t/water-level-in-tank/73947/1 "2023-01-20T09:52:10Z")
Hello Guys,
we install JSN-SR04T in a water tank with 120cm height .
and below is the code but my problem is that the tank now is empty but it gives me 80% when pressing the button
```auto
[
{
"id": "2a29abc4.be4324",
"type": "exec",
"z": "e86239c2.ac7248",
"command": "sudo python /home/pi/ultrasonic.py",
"addpay": "payload",
"append": "",
"useSpawn": "false",
"timer": "",
"winHide": false,
"oldrc": false,
"name": "",
"x": 400,
"y": 180,
"wires": [
[
"9971de04.727c6"
],
[],
[]
]
},
{
"id": "9971de04.727c6",
"type": "function",
"z": "e86239c2.ac7248",
"name": "",
"func": "var distance = parseInt(msg.payload);\nvar EmptyDist = 120 - distance;\nmsg.payload = parseInt((EmptyDist/120)*100);\n//msg.payload =(100- parseInt((temp/125)*100));\nreturn msg;",
"outputs": 1,
"noerr": 0,
"initialize": "",
"finalize": "",
"libs": [],
"x": 730,
"y": 180,
"wires": [
[
"b1617d6f.12bf9"
]
]
},
{
"id": "b1617d6f.12bf9",
"type": "ui_gauge",
"z": "e86239c2.ac7248",
"name": "",
"group": "99602dee.56223",
"order": 1,
"width": 0,
"height": 0,
"gtype": "wave",
"title": "",
"label": "%",
"format": "{{value}}",
"min": 0,
"max": "100",
"colors": [
"#00b500",
"#e6e600",
"#ca3838"
],
"seg1": "",
"seg2": "",
"diff": false,
"className": "",
"x": 900,
"y": 180,
"wires": []
},
{
"id": "a8b70e6a.6305",
"type": "ui_button",
"z": "e86239c2.ac7248",
"name": "",
"group": "99602dee.56223",
"order": 2,
"width": 0,
"height": 0,
"passthru": false,
"label": "button",
"tooltip": "",
"color": "",
"bgcolor": "",
"className": "",
"icon": "",
"payload": "",
"payloadType": "str",
"topic": "topic",
"topicType": "msg",
"x": 160,
"y": 240,
"wires": [
[
"2a29abc4.be4324"
]
]
},
{
"id": "99602dee.56223",
"type": "ui_group",
"name": "Fuel Tank",
"tab": "94549.2567dab8",
"order": 1,
"disp": true,
"width": "6",
"collapse": false,
"className": ""
},
{
"id": "94549.2567dab8",
"type": "ui_tab",
"name": "Fuel Level",
"icon": "dashboard",
"disabled": false,
"hidden": false
}
]
```
ultrasonic.py
```auto
import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
TRIG = 23
ECHO = 24
#print "Distance Measurement In Progress"
GPIO.setup(TRIG,GPIO.OUT)
GPIO.setup(ECHO,GPIO.IN)
GPIO.output(TRIG, False)
#print "Waiting For Sensor To Settle"
time.sleep(2)
GPIO.output(TRIG, True)
time.sleep(0.00001)
GPIO.output(TRIG, False)
while GPIO.input(ECHO)==0:
pulse_start = time.time()
while GPIO.input(ECHO)==1:
pulse_end = time.time()
pulse_duration = pulse_end - pulse_start
distance = pulse_duration * 17150
distance = round(distance, 2)
print distance
GPIO.cleanup()
```
---
### Author:  [@jbudd](https://discourse.nodered.org/u/jbudd)
#### Post date: [20 January 2023 10:00 UTC](https://discourse.nodered.org/t/water-level-in-tank/73947/2 "2023-01-20T10:00:16Z")
When you run ultrasonic.py from the command line it reports 80% ?
If so, you might get better support at the Raspberry Pi forum, without mentioning Node-red.
If not, can you show us what it does report - debug nodes to show output of the exec and function?
---
### Author:  [@pierrot](https://discourse.nodered.org/u/pierrot)
#### Post date: [20 January 2023 10:18 UTC](https://discourse.nodered.org/t/water-level-in-tank/73947/3 "2023-01-20T10:18:23Z")
> [@jbudd](#):
>
> When you run ultrasonic.py from the command line it reports 80% ?
no when i run the ultrasonic.py command the value is 23
---
### Author:  [@jbudd](https://discourse.nodered.org/u/jbudd)
#### Post date: [20 January 2023 11:17 UTC](https://discourse.nodered.org/t/water-level-in-tank/73947/5 "2023-01-20T11:17:47Z")
Maybe there will be something useful [here](https://discourse.nodered.org/t/announce-node-red-contrib-tank-volume-beta/47101) .
---
### Author:  [@pierrot](https://discourse.nodered.org/u/pierrot)
#### Post date: [23 January 2023 11:48 UTC](https://discourse.nodered.org/t/water-level-in-tank/73947/6 "2023-01-23T11:48:19Z")
the issue was the long distance between the rpi and tank .
do you know how far can we install the sensor from the rpi ?
---
### Author:  [@jbudd](https://discourse.nodered.org/u/jbudd)
#### Post date: [23 January 2023 11:54 UTC](https://discourse.nodered.org/t/water-level-in-tank/73947/7 "2023-01-23T11:54:44Z")
> [@pierrot](#):
>
> do you know how far can we install the sensor from the rpi ?
No idea!
Use an arduino/ESP32 at the tank to read the sensor and MQTT over ethernet/wifi to communicate to Node-red on the Pi.
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [24 March 2023 11:54 UTC](https://discourse.nodered.org/t/water-level-in-tank/73947/8 "2023-03-24T11:54:57Z")
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