After struggling to calibrate using official procedures, I started using math. Would love to know what you guys think of this.
What did not work: I've tried official procedure of poking small hole in a reference cup, measuring 8 oz of water and trying to adjust the screws based on percentage of error, had big difficulties getting any meaningful accuracy in adjustment and tests would take a ton of time. After that I've tried getting a dropper and made sure there were equal number of drops between the bucket (aka collector cup; aka self emptying rain collector) tips, followed by the 8 oz cup calibration. Again that took far too long and did not bring me closer to meaningful calibration. Here is what I ended up doing in order to get perfect 1.06" out of 8 oz.
What worked: I ended up realizing that in order to get 1.06", 8 oz of water needed to tip the rain bucket 106 times, thus each "tip" should carry (8 oz / 106) = 2.232 milliliters of liquid. Next I went to my local walgreens and asked the pharmacy to give me an accurate syringe with milliliter (ml) or cubic centimeter (cc) [1ml = 1cc] markings (they are free if you ask them nicely). Syringe I got from walgreens had 1ml major (larger) markings, each separated by four 0.2 ml minor (smaller) markings. So here is what I did to accurately calibrate the unit:
Before we get started, I would like to recommend that you try to calibrate the sensor where it is installed, do not take it elsewhere as recommended by official procedure. Sometimes this will not be possible, due to the height at which the sensor is installed, but you will get better accuracy if you calibrate the sensor right where it will be used. This calibration will take care of any slight deviation, if any, from perfect level, so calibrating it while the unit is leveled elsewhere will not be as effective.
What you will need: A phillips head screwdriver (to adjust the calibration screws), a cup of water, a syringe with ml or cc markings (usually available from a local pharmacy) and something narrow which could fit into the drain slots (a drinking straw can work).
What is NOT needed: Connection to the display / internet bridge. This calibration will use visual observation and information from the syringe, I recommend you remove at least two bottom batteries to stop the sensor from transmitting while you are doing calibration. This will prevent the weather data from being contaminated with false rainfall readings.
What did not work: I've tried official procedure of poking small hole in a reference cup, measuring 8 oz of water and trying to adjust the screws based on percentage of error, had big difficulties getting any meaningful accuracy in adjustment and tests would take a ton of time. After that I've tried getting a dropper and made sure there were equal number of drops between the bucket (aka collector cup; aka self emptying rain collector) tips, followed by the 8 oz cup calibration. Again that took far too long and did not bring me closer to meaningful calibration. Here is what I ended up doing in order to get perfect 1.06" out of 8 oz.
What worked: I ended up realizing that in order to get 1.06", 8 oz of water needed to tip the rain bucket 106 times, thus each "tip" should carry (8 oz / 106) = 2.232 milliliters of liquid. Next I went to my local walgreens and asked the pharmacy to give me an accurate syringe with milliliter (ml) or cubic centimeter (cc) [1ml = 1cc] markings (they are free if you ask them nicely). Syringe I got from walgreens had 1ml major (larger) markings, each separated by four 0.2 ml minor (smaller) markings. So here is what I did to accurately calibrate the unit:
Before we get started, I would like to recommend that you try to calibrate the sensor where it is installed, do not take it elsewhere as recommended by official procedure. Sometimes this will not be possible, due to the height at which the sensor is installed, but you will get better accuracy if you calibrate the sensor right where it will be used. This calibration will take care of any slight deviation, if any, from perfect level, so calibrating it while the unit is leveled elsewhere will not be as effective.
What you will need: A phillips head screwdriver (to adjust the calibration screws), a cup of water, a syringe with ml or cc markings (usually available from a local pharmacy) and something narrow which could fit into the drain slots (a drinking straw can work).
What is NOT needed: Connection to the display / internet bridge. This calibration will use visual observation and information from the syringe, I recommend you remove at least two bottom batteries to stop the sensor from transmitting while you are doing calibration. This will prevent the weather data from being contaminated with false rainfall readings.
- Understand that calibration of each side is independent of the other, don't try to calibrate both sides at the same time. Do one side first and than the other.
- Don't worry about screws not being adjusted by the same amount at this time, this procedure does not require it.
- My final calibration ended up being 25 quarter turns for the screw nearer the pole mount and 15 quarter turns for the screw farther the pole mount, you may want to start there and make adjustments as necessary. I counted quarter turns from the screws being screwed in all the way (my 0 point).
- Pick a screw to calibrate, as an example we'll start with the screw nearest to the pole mount. Start by carefully inserting a straw or a similar slim object into the drain by the other (far) screw. This will tip the cup onto the screw you are calibrating and make sure you are starting with no water in the cup.
- Fill a syringe with about 5ml of liquid and start slowly pouring the liquid into a rain funnel. Your goal is to get to the point where it tips after you poured in 2.2 ml (with 2.8 ml remaining in the syringe if you have started with 5 ml). You can start quick and pour in 1.2 ml a bit faster, than you should slow down and start dripping in the last 1 ml carefully, stopping when the cup tips.
- If you have started with 5ml, your goal should be (5 - 2.2) = 2.8 ml to be left in the syringe. If the cup tipped too early (you have more than 2.8 ml remaining) unscrew the screw you are calibrating a bit further (you need to decrease the amount left in the syringe, conveniently th...