# Using AMPL with Node red

**URL:** <https://discourse.nodered.org/t/using-ampl-with-node-red/9602>\
**Category:** General\
**Created:** [30 March 2019 08:48 UTC](https://discourse.nodered.org/t/using-ampl-with-node-red/9602 "2019-03-30T08:48:36Z")\
**Posts on this page:** 1\
**Showing post:** 9

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**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:** [30 March 2019 10:13 UTC](https://discourse.nodered.org/t/using-ampl-with-node-red/9602/9 "2019-03-30T10:13:27Z")

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By the way, others here have solved the irrigation problem by using PID control of the water injection to control soil moisture content.

Also I think the DHT22 is considered a poor sensor, by some at least. See

> [@DHTT22 zero values](https://discourse.nodered.org/t/dhtt22-zero-values/7465):
>
> Have been using node-red-contrib-dht-sensor with DHT22 sensor showing zero values in temperature and humidity : (object \_msgid: "2bea0790.4d4168" topic: "rpi-dht22" payload: "0.00" humidity: "0.00" isValid: false errors: 4 sensorid: "dht22" }. Anyone has any idea what went wrong? I'm using the Physical Pin Rev.2 with pin 15. All other grounded + power(3.3) are placed correctly. Much Appreciated

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