[hvalentim]

Last night I have spent a few hours doing my homework and reading all posts here. I believe I have now a clear picture of all options in my mind. Bellow I post three doubts I have plus a round-up of what I am planning. I would be much obliged if you could provide some feedback on these.

PART A – MY CURRENT DOUBTS

1 – Since we have no control over when the Auriol rain meter transmits (whenever it rains) there is a good change the signal may at times collide with the TX unit, correct? How does the RX handle this?

2 – I am missing the ability to log the data without the need to have the RX connected to a computer all day. Is this what the IC1 AT45DB011D-SSH-B Flash Memory is meant for in the long run?

3 – As far as the Right Angle Telephone Jack6P4C (for plugging the FineOffset sensors) is concerned, there is a note in the parts lists mentioning "My TX board include this parts already soldered on the board" but I do not seem to see these in the board photo. Do I need to buy them separately yes or no?


PART B – NOTES ON OPTIONS TO BE MADE AND PARTS NEEDED

Overall planned system architecture:
1. Will start with one singe TX unit (it will be placed 6 meters up on the roof but in the limit the wires can be extended just enough to place the humidity and temperature sensors closer to the ground as it’s meant to be the standard. Ideally, one should build a second TX unit so to as make this placing more flexible but I think I will leave this as a long run prospect.
2. Will fit the RX with re-transmitting abilities in case in the future I wish to build Display units. Not now.
3. Will retrofit my current radiation shield with a 12V fan.
4. Will power the TX from solar.
5. Really must build the solar measuring part as one can do many funny things with this data.

Sensor options:
• Temperature and humidity: SHT11. As these can be connected through an extension wire (up to 6 meters long) and placed on the radiation shield separate from the TX unit without the need for particular tweaking
• Will also order a SHT21 particular model capable of taking a 1 meter long cable just for the sake of it (the TX unit can take the two simultaneously). Actually, this would be enough to replicate my actual setup, which nevertheless is not the best in terms of placement.
• Pressure: BOSCH BMP180. The sole apparent advantage being it consumes less power
• UV: UVM-30
• Will use an Auriol wireless Rain-meter
• Will use the Fine Offset wind sensors

Further stuff and particular needs:
• 2 SMA 433Mhz tuned whip type antennas (not as pretty as the short twisted wire models but work better). This falls close to the ham band. Should be easy to get from amateur radio shops.
• 1 heat sink to apply to the 9V regulator as I plan to have a fan running.
• One 10W minimum solar panel + 1 12V gel battery + one STECA/XUNZEL or similar solar regulator.
• Better use an LCD screen and leave more resources available on the Arduino.

For the solar radiation portion:
• One solar cell (1V - 100mA ?)
• One original AD822ANZ OP signal amplifier
• One variable resistor acting as shunt (100 ohm ?)
• Adjustable resistors to get the correct bias/offset.
• waterproof case with a clear acrylic cover (for housing, this should not be placed more than 1-1.5 meters away from TX unit)
• Generic board for assembling as it does not seem WerkAG will make a kit available soon.

[werk_ag]

By your post it's clear, that you have now a good overall view of the system.

So, replying to your doubts:

1 – Since we have no control over when the Auriol rain meter transmits (whenever it rains) there is a good change the signal may at times collide with the TX unit, correct? How does the RX handle this?

What Auriol rainmeter sends, is a value with a total rain tips, since last reset (or battery change). It sends this data almost every 36 seconds. Even if one packet is lost or not decoded (it may happen) likely the RX unit will get the next. So in the worst case, the last occurred rain tip is recorded with a 36s delay. The RX unit, records in eeprom last total rain tips every 10 minutos (to save eeprom life, only if they differ from previous).

2 – I am missing the ability to log the data without the need to have the TX connected to a computer all day. Is this what the IC1 AT45DB011D-SSH-B Flash Memory is meant for in the long run?

It's supposed to have the RX (I think you meant say RX, and not TX) unit always connected to a computer or a Raspberry. But your best guess about the IC1 can not be very far from the true.

3 – As far as the Right Angle Telephone Jack6P4C (for plugging the FineOffset sensors) is concerned, there is a note in the parts lists mentioning "My TX board include this parts already soldered on the board" but I do not seem to see these in the board photo. Do I need to buy them separately yes or no?

TX boards come with those two connectors already soldered on the board.

Will also order a SHT21 particular model capable of taking a 1 meter long cable just for the sake of it (the TX unit can take the two simultaneously).

Yes, it can. One will be your main Temp / Hum sensor, the other is treated as an Extra Sensor.

Just a note for the solar radiation portion:
Carefully read all the info already available on the forum. It's very important fully understand how it works, before trying to build it.
With a common 1V - 100mA solar cell, the shunt resistor will be around 1.5 Ohm (here, a 0.1 Ohm will do a great difference).

[hvalentim]

Thanks a lot for your clarifications.

What Auriol rainmeter sends, is a value with a total rain tips, since last reset (or battery change). It sends this data almost every 36 seconds.

Wonderful. Had no idea about this. So there is no problem. The worst it can happen is very slight delay, but data will not be lost.

(I think you meant say RX, and not TX)

Correct. I meant the Reception (RX Unit). It was a typo.

Just a note for the solar radiation portion...

I understand that. This is not something to be done tomorrow. It will take it's time, testing and a bunch of spares as I am sure I will make plenty mistakes along the way.

[AllanG]

2 – I am missing the ability to log the data without the need to have the TX connected to a computer all day. Is this what the IC1 AT45DB011D-SSH-B Flash Memory is meant for in the long run?

It's supposed to have the RX (I think you meant say RX, and not TX) unit always connected to a computer or a Raspberry. But your best guess about the IC1 can not be very far from the true.

I'm very glad that memory may soon be added, the absence of it is the only (very small!) problem for me right now with the WeatherDuino project. Although my existing station is always connected to a PC, there are frequently times when it is necessary to shut it down - if I'm doing maintenance on the system or power supplies or restarts after regular Windows updates for example. These are usually quite short periods but there are of course occasions when things go wrong and it takes longer to reboot. It's good to know that the Fine Offset receiver is still logging the data and the computer running Cumulus will "catch up" when it is restarted. I would miss that reassurance!

Allan

[hvalentim]

List of parts I just ordered.

:: Generic for all units


3PCS Micro-controller Nano V3.0 ATmega328 5V/16M CH340G board For Arduino
(1 accounting for defect, mounting damage or in the best case scenario a possible additional TX unit)
http://www.ebay.com/itm/141287092498

:: Humidity & Temperature Sensors


Digital Temperature & Humidity sensor SHT15
(for outside TX unit, should work with long wires.
Costs twice an SHT11, likely not justified. But since I am at it and will invest the time, rather try to achieve the best possible quality)
http://www.ebay.com/itm/181192513879


SHT21 Digital Humidity And Temperature Sensor Module
(for outside TX unit, for use with a short wire or will need and I2C extender)
http://www.ebay.com/itm/221685877037


New HTU21D Temperature & Humidity Sensor Breakout Board Module
(limited by short wire or will need and I2C extender, can eventually replace the DHT22 inside)
http://www.ebay.com/itm/251643554884


DHT22/AM2302 Digital Temperature Humidity Sensor
(inside RX unit)
http://www.ebay.com/itm/221546295018


3x Plastic Cover for SHT10 SHT11 Temperature Humidity Sensor SCM
(should fit the SHT15 as well, not entirely sure about the SHT21, we will see...)
http://www.ebay.com/itm/381090103576

:: Pressure sensor


2 x 1PCS BMP180 Replace BMP085 Digital Barometric Pressure Sensor Module for Arduino
(1 as a spare)
http://www.ebay.com/itm/271453913203

:: Solar partion


http://www.ebay.com/itm/121222634881?_tr...EBIDX%3AIT
UVM-30A UV Detection Sensor Module Ultraviolet Ray Module for Arduino
http://www.ebay.com/itm/121222634881


2 PCS AD822ANZ DIP-8 AD822AN AD822 Rail-to-Rail Low Power FET-Input Op Amp
(1 as a spare)
http://www.ebay.com/itm/301222518099

---

:: RX Unit Specific Parts


2pcs DS3231 AT24C32 IIC Module Precision RTC Module Memory Module
(1 as a spare)
http://www.ebay.com/itm/371071190235


PC Board PCB Mount SMA Female Jack Nut Bulkhead Right Angle Connector new
(since I am a it, will fit the RX with re-transmitting capability for eventual future WD unit)
http://www.ebay.com/itm/261127442621


10PCS 2N7000 TO-92 MOSFET N-CHANNEL 60V 0.2A Transistor
http://www.ebay.com/itm/130963369289


Blue Display IIC/I2C/TWI/SP??I Serial Interface2004 20X4 Character LCD Module
http://www.ebay.com/itm/161095107719


Geeetech 433Mhz Superheterodyne 3400RF Transmitter and Receiver link kit,Arduino
http://www.ebay.com/itm/200974005470

:: TX Unit Specific Parts


3 x 1PC TMP36GT9 TMP36GZ 100%-Genuine New from ADI Low-Voltage Temperature Sensors
(1 for spares 1 for future additional TX unit)
http://www.ebay.com/itm/181092361353


2x 2PCS 433Mhz WL RF transmitter and receiver link kit for Arduino/ARM/MCU Good
(spares and space for a second TX unit)
http://www.ebay.com/itm/381090103576

Hope I got it all right.

Total spent, including shipping, the spares provisioned and the fact I purchased more sensors than actually required: 119,43 USD

Curiously enough, a number of dealers seem to be off on holidays. I guess because of Chinese New Year.

I am still missing a number of the small stuff, which I expect it would be easy to get either from local shops or from Farnell.

[werk_ag]

Really nice and helpfull post, and really nice choice of parts too! Nor the Davis uses SHT15 sensors.
Even with just one TX unit, you can connect the SHT15 and the SHT21 and get data from both. Just select on the software, which one is your main outside temperature / humidity sensor, and the other will be shown in Cumulus as an Extra Sensor (this feature will be extended in future software releases).

[hvalentim]

Looking at it more carefully, I don't thing either the SHT15 or the SHT21 (or the HTU21D, since both have the same chip and board form factors) will fit the plastic cover. Not without some tweaking/cutting.

You will notice the SHT10/1 board narrows a bit at some point and then widens to the part with the four pins. I think the idea is to leave the pins (and the plug they go into) outside of the cover. But the SHT15 (first pic bellow) narrow part is actually larger than the SHT10/1 one (second pic bellow) and will not fit.





Either way a board such as this one seems more handy:



I think I will use right angle pins with the SHT21.




Actually there is a world of right angle 4 pin connectors around ...

Does anyone know (or can better than me guess) the Pitch Spacing of pins in the SHT1x series boards? 1 mm? 2mm?

[werk_ag]

Looking at it more carefully, I don't thing either the SHT15 or the SHT21 (or the HTU21D, since both have the same chip and board form factors) will fit the plastic cover. Not without some tweaking/cutting.

I'm almost 100% sure that yours SHT21 and HTU21D will fit inside the plastic cover. You will be surprised how little those modules are.

Actually there is a world of right angle 4 pin connectors around ...

Does anyone know (or can better than me guess) the Pitch Spacing of pins in the SHT1x series boards? 1 mm? 2mm?

I'm not absolutely sure, but I think they are 2.54mm

[Brett]

the SHT modules are all universally 0.1" headers, so are breadboard friendly. Anything not on this "standard" header size are noted in specs when you buy them - you can be very comfortable if it doesn't call it out specifically, you'll find 0.1" header.

Personally, I would NOT go with the SHT10 module you show that has both 0.1" header and the shielded connector (the blue board without the narrowed waist). The Sensiron data sheets all talk about managing heat transfer into the sensor by doing things like the others do, and the blue board does none of that so is likely more affected by the external conditions than they should be.

[meteoestarreja]

That's really an useful post.
I just want to advise that in Superheterodyne 3400RF, you should always choose a model with those little plate on TX module.
Chinese people are always trying to lower the price and somewhere on the way, they start to take parts out ...
In longer distances, and in polluted environments (RF pollution), that little shield, could make the difference.
I prefer to pay 10 cents more, and buy a "shielded version"