Repair of Honeywell HIH4000 Humditiy Sensor - Page 1
Forum section: electronics / repair

author: kolbep
author_rank: Frequent Contributor
timestamp: January 24, 2015, 01:24:08 pm
content: Hi All.My customer has an irrigation controller for their Cucumber tunnels.The humidity sensor has packed up.It is a Honeywell HIH4000 SensorThis sensor takes 5v andGround in, and gives out a voltage relative to the humidity.But there is a problem where the sensor is continually outputting the Input voltage.New ones are quite pricey, so I was wondering if there are any tips on how to correct it.The Datasheet is here :http://sensing.honeywell.com/honeywell-sensing-hih4000%20series-product-sheet-009017-5-en.pdfThanksPeter

author: SeanB
author_rank: Super Contributor
timestamp: January 24, 2015, 01:58:06 pm
content: The sensor is a single sealed unit, so you probably want to get another one with voltage output, or one with I2C or frequency output, and use a microcontroller to give a voltage output for it. Will be a little bigger, but will do, and then you will have the ability to use more sensor types.http://www.adafruit.com/category/66Otherwise they are only $18 on eBay....http://www.ebay.com/itm/1pc-Honeywell-HIH-4000-001-Relative-Humidity-Sensor-Hygrometer-Moisture-USA-/160747625438?pt=LH_DefaultDomain_0&hash=item256d4e1bdeNot affiliated to seller, and likely a drop shipper in any case from PRC, so order fast before China closes for the new year, and as SAPO is going on strike ( Fark, AGAIN) on Monday, you probably will want to arrange with them for shipping via courier, or use a reshipper who will do that. Likely will cost more than the part, so buy a few.

author: wraper
author_rank: Unknown
timestamp: January 24, 2015, 01:58:59 pm
content: How do you suppose to repair integrated circuit? You could ask if you can repair failed MOSFET or RAM IC with the same extent. Not that expensive BTW.Quote

author: kolbep
author_rank: Frequent Contributor
timestamp: January 24, 2015, 02:24:55 pm
content: I was thinking maybe there could be some magic trick,like maybe baking at some temp for some time.Oh well, Let me quote them on a new one.Thnks

author: wraper
author_rank: Unknown
timestamp: January 24, 2015, 02:31:22 pm
content: Quote from: kolbep on January 24, 2015, 02:24:55 pmIn the cases when such a trick works, like if the bonding wire lost its contact, that usually helps only for a short time.

author: dfmischler
author_rank: Frequent Contributor
timestamp: January 24, 2015, 02:33:05 pm
content: Lookhere. Pick the one that matches your requirements (filter, or not?). I bet the HIH-5030 series would drop right in to your circuit; check the datasheets. Quantity one price is a bit over half of the price of a HIH-4030 part, and it will work over a wider supply voltage range.

author: kolbep
author_rank: Frequent Contributor
timestamp: January 25, 2015, 03:14:26 pm
content: Quote from: dfmischler on January 24, 2015, 02:33:05 pmThanks for the tip. the HIH-5030 is a lot cheaper (can get 2 for the same price as the 4030). Let me check with the customer, and get their go-ahead.BTW. this Aquarius Smart Control System is made in Cape Town, South Africa.It consists of a Daylight Sensor module, that interprets the daylight shining on a white dome. (That goes Just outside the greenhouse tunnel)It has another module that has the Humidity and Temperature Sensors, and that is inside the tunnel.They communicate to the control module using an RS485 Signal. Both the Sensor Modules, and the Control Modules use Atmel uC.'sIt calculates the energy used by the plants based on the Light Exposure, Temperature, and Humidity. And then when it thinks it is time for a watering, it pulses a relay.There is a Multizone Irrigation Controller that then picks up this pulse, starts the waterpump and Main Valve. It then Opens each tunnels solenoid valve for a preset period, to water each tunnel.P

author: dfmischler
author_rank: Frequent Contributor
timestamp: January 25, 2015, 03:37:23 pm
content: Quote from: kolbep on January 25, 2015, 03:14:26 pmHow big are the tunnels? What is the watering technique (e.g. drip irrigation)? Air humidity is probably useful if you are trying to measure plant transpiration, but otherwise I am not so sure (many systems use soil moisture). Don't you also need to know CO2 levels to measure transpiration? What about plant growth stage and how that affects water transport from soil to the air?

author: kolbep
author_rank: Frequent Contributor
timestamp: January 25, 2015, 05:13:54 pm
content: Quote from: dfmischler on January 25, 2015, 03:37:23 pmThe Customer has 20 Tunnels,Each is 30m(l)x8m(h)x4m(w).I believe it is low pressure sprinkler heads that they are using.I dont know much about Cucumber Farming. I was just called in to check the errors this control system was giving.