Cumulus Support

Hi,

wetterfrosch1971 wrote:The Temperature-Sensor works exactly, but the Humidity-Sensor is worn.

There have been several different types of humidity sensor fitted in these stations and I thought the more recent versions use the same sensor for temperature and humidity. However, it should still be on a small module or "daughter board", so quite easy to exchange. See photos # 4 and # 11 on the first page of this thread.

Cheers, Alan.

Hi,

I have two different transmitter, look at the pictures, once with a "daughter board" and once without.
But both have a white component, is this the Humidity-Sensor?
But I can not find a name on the White component, if this are the humidity-sensor, what is the name or were I can buy it?

Many thanks for help.

Probably an SHT11 or similar.
They seem to be about £2 or so on ebay.

anxiousmac

Hi,

Possibly worth a try, but it could be a SHT/DHT 15 or 21, or AM2301, etc.. First thing to check is if it's using 2, 3 or 4 wires/pins to connect to the main board. That may help determine if it's an I2C, SPI or a "one-way" data bus.

The sensor is probably made by the Chinese company "Hope Microelectronics", but AFAIK they only/mainly supply to OEMs, not distributors.

The "White module" on the daughter board of one of my transmitters is the humidity sensor, but uses only 2 pins. Two pads marked NTC are not populated and there appears to be a SMD chip on the underside.

Cheers, Alan.

Hi,

SHT11 has 4 pins,
but the sensor in my transmitter has only 2 pins.

does anyone know the correct type for the sensor?
My sensor has only 2 Pins, which sensor can I install?

Many thanks
Frank

If it only has two terminals, it is probably a "Capacitor" - Analogue type humidity sensor.
The value of the capacitance change as the humidity change. I see a "Thermistor" next to it, i presume that is the local temperature reading, also Analogue.
The 4 wire type is a "Digital" type where the sensor values, Humidity and temperature, is read by the onboard processor.

Just a quick message in an Old thread relating to the post on page 3 by Ben about the solar charger.

Has anyone tried to add a small solar charger panel to a non solar charge sender ?? as in since the rain data is sent to the the sender on pins 2 & 4 and the solar power is sent on pins 3 & 5 (as far as I worked out from the info) could a small solar panel be wired to pins 3 & 5 and turn the non solar charging sender into an adhoc solar charging sender and change the normal AA batteries out for rechargable AA batteries or has the solar charger pod got hidden electronics that controll the charge current etc.

I bought my setup second hand a couple of years ago and just before Maplins hit the wall I bought a couple of spares, (a sender and a wind vain) but I am not sure if the sender will work with the old lcd station as it seems to be made before they chaged tx protocol and I do not fancy trashing my working tx sender if the replacement will not talk to the old lcd station.

I started a project to build an external solar battery bank so that the batteries would never need changed again ( I am disabled and access to the outside unit is HARD ). I got hold of a little 3 inch by 2 inch solar panel and 3D printed a housing / mount to hold the small panel, to get the ball rolling but things have been n hold for over a year now and I am just getting back on my feet again so started to look into this project again.

If it is possible I can proto a small pcb with rj11 socket for the rain gauge plug and + and - power from the small solar panel and run a wire with 4 cables and rj11 plug to the sender and hey presto a solar charging sender upgrade for a couple of quid.

Hi,

Welcome to the forum. To answer a few of your questions:

The "Solar Pod" (for solar data) contains quite a lot of electronics including a "voltage regulator" which feeds current to the batteries in the main transmitter unit. It takes the form of an ultra low quiescent current (a few uA) 3.3 volt regulator followed by a Schottky diode (~300 mV forward drop) to prevent current flowing back out of the batteries. Thus it feeds about 3.0 volts to the "rechargeable" batteries, which IMHO is quite useless. It's too low for any "good" rechargeable batteries e.g. LiFePO4 (3.2 volts/cell) or NiZn (1.6 volts/cell) and probably too low for even the horrible "rechargeable Alkalines" supplied. Best choice is probably a pair of NiMH cells (1.2 volts each) although you might find the Console's "Low Battery" icon comes on quite a lot (and the regulator won't limit the charging current into even fully charged batteries).

A starting point for the transmitter is: Does the "Rain" socket have 4 or 6 "wires" in the "RJ11/12" socket?. If it has only 4 wires (6P/4C) then there isn't any connection/contact to the battery (the Solar Pod uses a 6P6C RJ12 plug, with 5 wires actually connected). However, I also bought a new Transmitter unit from Maplin just before they went to the wall, which did have 6 contacts in the Rain Socket, but still I wasn't able to feed any current into the batteries, so I had to assume that the Solar Charging/Data Transmitters are different to those being sold by Maplin .

Of course you could still make an external connection directly to the batteries and charge it from a small solar panel. Start with a couple of "Low Self Discharge" (aka Hybrid) NiMH cells but if the Low Battery Icon is annoying, or the transmitter range is unsatisfactory, then try NiZn or preferably one LiFePO4 cell (plus a "placeholder" cell), as sometimes sold as a replacement for those in the better quality "Solar Garden Lights". LiFePO4 cells are moderately tolerant of over-charge so probably don't need a regulator with a small panel (a few square cms).

Cheers, Alan.

I'm wondering why you'd want to bother with a solar charger? A pair of AA alkaline from Aldi lasts more than 2 years, and even if yours is on the roof you'd need to be up there more often than that to clean the spiders out of the sensors ...

"More than 2 years"? I'm lucky if I get 13 months from mine. I change them every October so that it has got a new set when the weather gets cold.

thanks for the quick answers. The unit is out about 1 meter above my outside shed/office and I think the reason the previous owner sold it was it eats a pair of duracell AA batteries every 6 months. The idea was to get the unit up on the chimney once it was 100% reliable. I have already fallen prey to the ultra super strong spider web holding the rain bucket/tipper in place and a little light reading later the holes were covered over with (car bodywork hole repair mesh) dunno what its correct name is but it is a fine Aluminium mesh designed to strengthen body filler when bodging car body work and fixed in place with clear hard setting resin (making sure the holes still worked as holes) and this has defeated them creepy crawly things perfectly.

I bought a 11000 MaH battery bank with solar cell built into it from a Fleabay china seller a good while ago for a couple of quid delivered (no 18650`s were supplied it was just a build it yourself case) with the intention of trying to come up with some kind of external power bank that could trickle charge via the solar cell. I designed and 3D printed a case/housing and made a dummy AA battery that is wired up to it. I used the electronics that come with the battery bank and added a step down buck to get 3.2v at the dummy battery and everything looked good during testing. It was ready for a friend to put on the roof chimney untill I found out one very very cold night that the Li-ion batterys charge dropped thru the floor rendering the whole thing a waste of time, So I am back to the drawing board again. I am about to wire the dummy AA battery pack to a nice little variable dc controller set to 3.2v and attached to one of my 12v Leisure batterys on my big solar bank I use for garden lights, my phone charger on my office, my 18650 vape battery charger etc etc etc so that while the station is on my office roof it will never need the batteries changed again.


Chris

Hi Chris,

Only the anemometer/vane (and Solar Sensors when applicable) need to be "on the roof", the "recommended" height for T/H and Rain sensors is only a few feet above the ground. The FO sensors are all cabled, which can be easily extended if required (provided that the RJ11/12 connectors are adequately water-proofed), so it needn't be too difficult to change the batteries (or locally recharge them).

Do you mean1100 or 11000 mAh for the power bank? 18650 cells are usually around 1000 - 3000 mAh each, not very different from a pair of Alkaline, NiMH or NiZn AA cells (in series). Draining these in 6 months still represents an average load of less than 1 mA, whilst the quiescent (no load) drain of most buck converters (and even simple three-terminal regulators like the 78Lxx) will be many mA. Note that most LDO regulators also have relatively high quiescent currents, but Microchip do make a family (through-hole and SMD) with uA values (I can't recall the type number but could look it up if required).

Finally, you might be "lucky" and have all your sensors work reliably for many years, but generally the best approach is to mount all the sensors so that they can receive regular maintenance if required.

Cheers, Alan.

Hi all, my windvane does not have relays as I expected, there are Hall sensors. Wiring is changed as well. Input from anemometer (two middle wires on RJ11) goes to two side position (WIND & GND on the picture) on the output RJ11, other two on the othere side are for windvane (VDD & DATA on the picture). I put 3,3V on the Vdd and I tried to measure something on the DATA, using pullup, pulldown, but the value was never stabile, it change continuously. Probably it is because there is a customized chip inside that process the signalling.
Have you experienced that? Does someone know how to connect it into Arduino?
Thanks.

Hi,

Thanks for the detailed information and welcome to the forum. My apologies for the delay in replying, but I had hoped that somebody might "know" the answer, I can only "guess". Unfortunately, I have never had a Hall Vane sensor to test.

I had assumed that the Hall Wind Vane was "compatible" with the original Magnetic Reed (relay) version, but your version clearly is not, because the pin connections are different. However, I believe the Hall version could be compatible with the Reed version (if the pin connections were different) which might give us a clue to how it works.

But first, do you have (access to) an Oscilloscope or Logic Analyser? Many sensors now use a "data bus" so can't be tested with only a multimeter, but the majority of these use (at least) two wires (in addition to supply and ground) but yours has only one. Unless the anemometer data is merged into the same data stream (which doesn't appear to be the case from the PCB layout and pin named "Wind"). The "Solar Pod" does transmit fully encoded data on a single pin/wire, but that is a complete data packet, whilst the wind direction is only a small part of the normal external sensors data packet. If the Hall Vane does use a data bus then I'm afraid you may need quite a lot of technical knowledge and perhaps equipment to determine how to use it.

However, let's assume that its basic operation is compatible with the original reed version: The reed sensor presents simply a "variable resistance" (across the two outer pins of the RJ11 plug) and most "third party" applications such as Auduino/Weatherduino connect one pin to ground, the other via a resistor to the Arduino supply rail and measure the voltage at the junction. However, this does not provide a supply rail to operate the Hall sensors, but the original Fine Offset "Transmitter" (ADC) is NOT connected like that. One of the Vane pins is connected (indirectly) to the Power Rail so the pin voltage is about 3 volts, which could supply the Hall sensors and the Microcontroller. The other pin connects to an ADC input, but this is also normally biassed at the supply voltage (to avoid significant current drain).

To read the Vane resistance, once every 48 seconds, the supply pin is briefly pulsed to ground (the Hall/Micro devices could continue to receive power from a decoupling capacitor) and the ADC measures the time for the resistance to (half) discharge a capacitor (typically 10uF). This is similar to the classical "Monostable Multivibrator" circuit which has a time constant of around 0.7 x C x R. Credit to "Gina" on this forum who discovered these details in around 2010

It would be quite difficult for the Vane Microcontroller to emulate a variable resistance accurately over a range of 660 ohms - 150 kohms (the reed version) so perhaps it emulates the pulse width created by the original ADC. Therefore, for your "Arduino" application, I suggest you take "Vdd" to 3 volts and briefly pulse it to ground (zero volts) for perhaps 100 ms (every few seconds) and see if there is any "response" on the "Data" pin.

Cheers, Alan.