Author Topic: New VP2 owner, need data logging cable  (Read 14658 times)

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Offline DanITman

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New VP2 owner, need data logging cable
« on: May 24, 2011, 11:12:08 AM »
I just received my Wireless VP2 and I would like to start collecting data. I'm aware of all my software options but I'm wondering where I can pick up a serial/usb cable.  Since I don't need the software I'm finding this to be very hard.  I might have to create it on my own but I would rather just pay the money and purchase one.  Anyone have a spare they want to sell?

I'm looking forward to contributing on this site.  It has already proven to be a great resource while deciding what to purchase and where to place my weather station.

I have big plans to incorporate the data collected into my irrigation system to better my watering schedules.  

Thanks
« Last Edit: May 24, 2011, 11:15:31 AM by DanITman »

Offline Bushman

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Re: New VP2 owner, need data logging cable
« Reply #1 on: May 24, 2011, 11:20:21 AM »
You already have the serial data logger?  If not, you can search DeKay's posts and see how to make a direct connect from the Console to your PC.  Otherwise you need a logger (~125 bucks).  If all you need is a serial to USB converter, there are scads of them for cheap at dealextreme.com  Get one with the Prolific chipset.

Offline DanITman

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Re: New VP2 owner, need data logging cable
« Reply #2 on: May 24, 2011, 11:24:51 AM »
No I don't have the logger but I'm wondering where I should purchase one.  I have read DeKay's post and have considered making a direction serial connection.  I just find it hard to pay $125.00 for something that can be made for under $10.  I almost wish someone would start selling just the cable because I think you would have a market for it.

Offline dalecoy

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Re: New VP2 owner, need data logging cable
« Reply #3 on: May 24, 2011, 11:40:55 AM »
No I don't have the logger but I'm wondering where I should purchase one.  I have read DeKay's post and have considered making a direction serial connection.  I just find it hard to pay $125.00 for something that can be made for under $10.  I almost wish someone would start selling just the cable because I think you would have a market for it.

It's not just a simple cable.  And I don't remember anybody saying that a copy/equivalent can be made for under $10. 

Offline DanITman

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Re: New VP2 owner, need data logging cable
« Reply #4 on: May 24, 2011, 12:02:17 PM »
No I don't have the logger but I'm wondering where I should purchase one.  I have read DeKay's post and have considered making a direction serial connection.  I just find it hard to pay $125.00 for something that can be made for under $10.  I almost wish someone would start selling just the cable because I think you would have a market for it.

It's not just a simple cable.  And I don't remember anybody saying that a copy/equivalent can be made for under $10.  

It all depends on the type of cable you are building.  You could keep the cost low by just doing a serial cable.  If you want USB the cost of the cable goes up.  I've built a similar cable for another project and the cost was around the $10 mark.

Here is one piece you will need if you want USB.  The cost is $15

http://cgi.ebay.com/FTDI-USB-RS232-TTL-Converter-FT232-FT232RL-3-3V-/120648223859?pt=Vintage_Electronics_R2&hash=item1c1731cc73

« Last Edit: May 24, 2011, 12:03:57 PM by DanITman »

Offline Bushman

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Re: New VP2 owner, need data logging cable
« Reply #5 on: May 24, 2011, 12:08:49 PM »
TO reiterate, the Davis logger is NOT a simple serial/USB cable.  It contains logging circuitry to retain the data from the station.  If you build your or Dekay's cable you WILL NOT get that memory and if it burps, you lose the current data and subsequent till it feels better.

Offline SlowModem

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Re: New VP2 owner, need data logging cable
« Reply #6 on: May 24, 2011, 12:14:38 PM »
No I don't have the logger but I'm wondering where I should purchase one.  I have read DeKay's post and have considered making a direction serial connection.  I just find it hard to pay $125.00 for something that can be made for under $10.  I almost wish someone would start selling just the cable because I think you would have a market for it.

You know how you can buy a printer cheap but the toner is outrageous?  That's how Davis dataloggers are.  It's a pretty good racket for Davis.
Greg Whitehead
Ten Mile, TN USA

http://www.wattsbarweather.net


Offline SLOweather

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Re: New VP2 owner, need data logging cable
« Reply #7 on: May 24, 2011, 12:19:10 PM »
How are you planning on incorporating the data into your irrigation system? I use a home automation program called HomeSeer, and import the data into it from VWS to do similar control.

FWIW, I've made a simple RS-232 serial cable for the VP2 console for about $25 in parts. As Bushman points out, it doesn't include a logger, buy the app for which I built it doesn't use the logger data, at least not at this time.

I used an off-the-shelf 3.3 v logic level to RS-232 adapter and a 2mm dual row header from Digi-Key.

Offline DanITman

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Re: New VP2 owner, need data logging cable
« Reply #8 on: May 24, 2011, 01:34:41 PM »
How are you planning on incorporating the data into your irrigation system? I use a home automation program called HomeSeer, and import the data into it from VWS to do similar control.

FWIW, I've made a simple RS-232 serial cable for the VP2 console for about $25 in parts. As Bushman points out, it doesn't include a logger, buy the app for which I built it doesn't use the logger data, at least not at this time.

I used an off-the-shelf 3.3 v logic level to RS-232 adapter and a 2mm dual row header from Digi-Key.

I'm glad you asked :)  I currently use a product called EtherRain.  Its and IP based irrigation controller that works very well.  It's has a well documented API and the guy who invented it wrote the Homeseer driver.  I've been playing with it for some time and I love it.

http://board.homeseer.com/showthread.php?t=136596

I want to use it to measure rain fall rates to determine when to water.  Right now I just use a rain sensor but I want something more accurate.  I can calculate how much water my lawn needs daily and then see how much rain it has received.  I would eventually like to calculate evapotranspiration as this is a more accurate number.  I think I'll need Solar Radiation Sensors to calculate this.

You can also use EtherRain in combination with their website lawncheck.com.  It allows you to set schedules and it uses Yahoo weather to predict rain and check rain fall rates. 
« Last Edit: May 24, 2011, 01:38:06 PM by DanITman »

Offline SLOweather

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Re: New VP2 owner, need data logging cable
« Reply #9 on: May 24, 2011, 02:25:34 PM »
Because of your interest in irrigation control, you might want to check out my SLOweather.com website. There you will see 2 different indexes, the Watering Index, and the Irrigation Index.

I created the Irrigation Index before I learned about the Watering Index.

The Irrigation Index is the running total of the last 7 days of rainfall subtracted from the running total of the last 7 days evapotranspiration or ET, as measured and calculated by the SLOweather weather station.

That tells you how much water in inches to put out this week.

The Watering Index was created by a California DWR engineer and is the percentage of the last 7 days running ET/highest weekly average ET for your area * 100.

On SLOweather, I've enhanced the WI by subtracting out the last 7 days rain from the ET to give a better representation.

Bottom line, get the solar sensor and use ET. You won't be sorry.



I'm glad you asked :)  I currently use a product called EtherRain.  Its and IP based irrigation controller that works very well.  It's has a well documented API and the guy who invented it wrote the Homeseer driver.  I've been playing with it for some time and I love it.

http://board.homeseer.com/showthread.php?t=136596

I want to use it to measure rain fall rates to determine when to water.  Right now I just use a rain sensor but I want something more accurate.  I can calculate how much water my lawn needs daily and then see how much rain it has received.  I would eventually like to calculate evapotranspiration as this is a more accurate number.  I think I'll need Solar Radiation Sensors to calculate this.

You can also use EtherRain in combination with their website lawncheck.com.  It allows you to set schedules and it uses Yahoo weather to predict rain and check rain fall rates. 

Offline DanITman

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Re: New VP2 owner, need data logging cable
« Reply #10 on: May 24, 2011, 03:02:17 PM »
Because of your interest in irrigation control, you might want to check out my SLOweather.com website. There you will see 2 different indexes, the Watering Index, and the Irrigation Index.

I created the Irrigation Index before I learned about the Watering Index.

The Irrigation Index is the running total of the last 7 days of rainfall subtracted from the running total of the last 7 days evapotranspiration or ET, as measured and calculated by the SLOweather weather station.

That tells you how much water in inches to put out this week.

The Watering Index was created by a California DWR engineer and is the percentage of the last 7 days running ET/highest weekly average ET for your area * 100.

On SLOweather, I've enhanced the WI by subtracting out the last 7 days rain from the ET to give a better representation.

Bottom line, get the solar sensor and use ET. You won't be sorry.



I'm glad you asked :)  I currently use a product called EtherRain.  Its and IP based irrigation controller that works very well.  It's has a well documented API and the guy who invented it wrote the Homeseer driver.  I've been playing with it for some time and I love it.

http://board.homeseer.com/showthread.php?t=136596

I want to use it to measure rain fall rates to determine when to water.  Right now I just use a rain sensor but I want something more accurate.  I can calculate how much water my lawn needs daily and then see how much rain it has received.  I would eventually like to calculate evapotranspiration as this is a more accurate number.  I think I'll need Solar Radiation Sensors to calculate this.

You can also use EtherRain in combination with their website lawncheck.com.  It allows you to set schedules and it uses Yahoo weather to predict rain and check rain fall rates.  

Very Cool, I love this.  What are you using to control your irrigation?  Do you need the UV sensor to calculate ET? Can you give me an example on how you would use the watering index % to determine how much to water your grass?

I also notice you are comparing 10 years worth of ET.  Are those the numbers you have collected?

« Last Edit: May 24, 2011, 03:06:25 PM by DanITman »

Offline SLOweather

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Re: New VP2 owner, need data logging cable
« Reply #11 on: May 24, 2011, 04:58:22 PM »

Very Cool, I love this.  What are you using to control your irrigation?  

Right now, an old controller that HS turns on and off. I think I'm going to check out your EtherRain referral, though. :)

Quote
Do you need the UV sensor to calculate ET? Can you give me an example on how you would use the watering index % to determine how much to water your grass?

All you need is the solar sensor, not UV. The Davis ET calc uses solar irradiance, wind, RH, and BP to calculate the running daily ET value from midnight.

For people with newer controllers than mine, it's pretty easy. The controller is set to water 100% for the highest weekly average ET. Here in California, that's usually in July.

Then, once a week, check the Watering Index, and set the knob or whatever on the controller to that percentage. The controller automatically adjusts each station accordingly.

I haven't gone overboard with getting my adjustments just right yet, because we only water about 100 square feet of turf for the dogs, some raised beds for veggies and flowers, and a native plant bird-and-butterfly garden that requires almost no supplemental water in the summer.

In HomeSeer, it's easy to pick up the station data from VWS and then script to control relays directly, or, like I do, just keep the controller from opening the solenoids.

Quote
I also notice you are comparing 10 years worth of ET.  Are those the numbers you have collected?

The State of California has a listing somewhere on-line of highest average ETs for various locations in the state. I got my info from there.

EDIT: Found the map... It's big, so here's the link:

http://www.cimis.water.ca.gov/cimis/cimiSatEtoZones.jsp

« Last Edit: May 24, 2011, 05:21:27 PM by SLOweather »

Offline DanITman

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Re: New VP2 owner, need data logging cable
« Reply #12 on: May 26, 2011, 03:22:09 PM »
TO reiterate, the Davis logger is NOT a simple serial/USB cable.  It contains logging circuitry to retain the data from the station.  If you build your or Dekay's cable you WILL NOT get that memory and if it burps, you lose the current data and subsequent till it feels better.

Has anyone actually taken one of these apart?  I have a feeling they are just a cable.  Isn't it the counsel that is keeping the history in memory?  I have a feeling the only components in the USB cable is a USB to serial converter.   Once I get my serial cable I'll open it up and take a look.

Offline Bushman

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Re: New VP2 owner, need data logging cable
« Reply #13 on: May 26, 2011, 03:41:21 PM »
Knock yourself out and possibly ruin the logger in the process.  If there was a console memory Dekay's simple direct connect cable would be passing data from memory in the console and not streaming data (whoch it does).

Offline SLOweather

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Re: New VP2 owner, need data logging cable
« Reply #14 on: May 26, 2011, 03:53:01 PM »
Has anyone actually taken one of these apart?  I have a feeling they are just a cable.  Isn't it the counsel that is keeping the history in memory?  I have a feeling the only components in the USB cable is a USB to serial converter.   Once I get my serial cable I'll open it up and take a look.

Good luck with that. The board is encapsulated in a hard rubber-like molding. It's certainly possible to cut away at it, I suppose. However, that cable pigtail is molded into it.

I'm sure that someone at some time has extracted the board from the molding, but, to my knowledge, that hasn't been reported here.

OTOH, it would be easier to connect a console with a true serial-only cable like the one I built, and see what happens when one tried to access the archive memory.

Remember, back when these were first designed, memory was more expensive, and it would have made sense to only put it in the interface cable.

Offline wxtech

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Re: New VP2 owner, need data logging cable
« Reply #15 on: May 26, 2011, 05:28:48 PM »
Don't bother whittling on your data logger.  I opened one several years ago.  I didn't post pictures then out of respect for Davis propriety rights for the device.  I've hacked most of the parts of the VP & VP2, and made modifications to most.
I can't find the old pictures but on the data logger circuit board, I see two IC's, a regulator, 2 diodes, 3 resistors, 11 capacitors plus J1 the 20 pin connector.  The black cable is soldered to 4 pads.  I'll have to get creative to read the IC part numbers. I don't know how many layers the circuit board has.  I didn't uncover the foil side of the circuit board.  I'll post a picture later.
Al
Al Washington, Lexington, Ga.,  NWS Coop station=LXTG1, Fischer Porter, SRG, MMTS. 
CoCoRaHS=GA-OG-1. CWOP=CW2074.  Davis VP2+ WLIP 5.9.2, VP(original) serial, VWS v15.00 p02. ImageSalsa, Win7 & Win8 all-in-one.

Offline Bushman

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Re: New VP2 owner, need data logging cable
« Reply #16 on: May 26, 2011, 05:51:36 PM »
It is not that difficult to make your own data logger.  heck t you can use a Casio or Ti calculator to log temps!  But for $120 bucks...

Offline wxtech

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Re: New VP2 owner, need data logging cable
« Reply #17 on: May 26, 2011, 05:57:15 PM »
On the datalogger circuit board,
U1 is an Atmel 45DB memory http://www.atmel.com/dyn/resources/prod_documents/doc3688.pdf,
U2 is a Maxim MAX3221E RS-232 Transceiver http://www.maxim-ic.com/datasheet/index.mvp/id/1781/t/do
U3 is probably a voltage regulator, it is unmarked.  All the other components are passive resistors, capacitors, diodes and a connector.
If anyone wishes to pursue this further, I'll trade this one for a new datalogger.   :lol:
« Last Edit: May 26, 2011, 05:58:51 PM by wxtech »
Al Washington, Lexington, Ga.,  NWS Coop station=LXTG1, Fischer Porter, SRG, MMTS. 
CoCoRaHS=GA-OG-1. CWOP=CW2074.  Davis VP2+ WLIP 5.9.2, VP(original) serial, VWS v15.00 p02. ImageSalsa, Win7 & Win8 all-in-one.

Offline SLOweather

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Re: New VP2 owner, need data logging cable
« Reply #18 on: May 26, 2011, 06:51:34 PM »
Thanks for posting that, Wxtech. That will quell a lot of wondering and speculation.

Offline wxtech

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Re: New VP2 owner, need data logging cable
« Reply #19 on: May 26, 2011, 08:37:35 PM »
I also have a Temp/Hum circuit board sensor opened to see what components are used.  I'll round that up and take new pictures of both devices that were previously encapsulated.
Al Washington, Lexington, Ga.,  NWS Coop station=LXTG1, Fischer Porter, SRG, MMTS. 
CoCoRaHS=GA-OG-1. CWOP=CW2074.  Davis VP2+ WLIP 5.9.2, VP(original) serial, VWS v15.00 p02. ImageSalsa, Win7 & Win8 all-in-one.

Offline DeKay

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Re: New VP2 owner, need data logging cable
« Reply #20 on: May 28, 2011, 05:01:55 PM »
On the datalogger circuit board,
U1 is an Atmel 45DB memory http://www.atmel.com/dyn/resources/prod_documents/doc3688.pdf,
U2 is a Maxim MAX3221E RS-232 Transceiver http://www.maxim-ic.com/datasheet/index.mvp/id/1781/t/do
U3 is probably a voltage regulator, it is unmarked.  All the other components are passive resistors, capacitors, diodes and a connector.
If anyone wishes to pursue this further, I'll trade this one for a new datalogger.   :lol:

NICE!  This is great information!  I was speculating that the dongle contained a small micro that managed storage of the data to a bit of on-chip memory.  But what you've proven is that the console itself does the work of writing the data to what is basically just a simple memory expansion that you could buy for less than a dollar!!!  That would also explain why Davis brings out the SPI lines to the expansion port.


If you were to pin out the connection between the expansion port and the dongle like I did between the processor and the expansion port, that would enable us to build our own dongles at a huge cost saving.  It would be simple to use a multimeter to do this without you even needing to uncover the foil side.

Heck, even without doing that, the pinout is mostly obvious if you take a look at the datasheet and my diagram above.  The trick (I'm guessing) is that the dongle likely has a short between a couple of the pins that lets the console sense the dongle is there and plugged in.  And I can even narrow that down: it should be between PB4, PE2, PE3, and PC4. 

It is possible too that none of them are and it would just work if this chip were connected up.  Wxtech, if you, or anybody else for that matter, would care to figure out which of these two pins are shorted together, that would be huge.  I'd be willing to take a shot at building one and sharing what I learn as I've done before.

And to DanITman: Bushman is right.  Unless you use a USB->Serial converter that converts to 0V -> 3.3V LVTTL levels rather than +/-10V (or whatever), you'll very likely fry your console.  Read the link in the last paragraph to see why.

Offline DeKay

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Re: New VP2 owner, need data logging cable
« Reply #21 on: May 28, 2011, 05:08:44 PM »
And of course, just after posting, it occurred to me that PB4, PE2, PE3, or PC4 could also either be pulled down to ground or pulled up to Vcc.  That should be checked for as well.

A general question to folks with the logger: is there an indication somewhere on the console display if a logger is plugged in?  Does the logger have to be plugged in when the console is powered up for it to be recognized, or can you plug it in anytime?

Offline dalecoy

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Re: New VP2 owner, need data logging cable
« Reply #22 on: May 28, 2011, 05:56:49 PM »
A general question to folks with the logger: is there an indication somewhere on the console display if a logger is plugged in?  Does the logger have to be plugged in when the console is powered up for it to be recognized, or can you plug it in anytime?

I don't know the precise answer to this question.  However, I do know that doing one or both of the following can (and usually does) cause the console to get "confused".

A.  Unplugging the logger when the console is powered.
B.  Plugging in the logger when the console is powered.

In particular, it is usually the case that - if the console is powered up - unplugging the logger and plugging it back in will cause logging to cease until there is a complete power reset.

"Powered" in the above seems to mean "power available" (that is, including the batteries).   

Offline DeKay

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Re: New VP2 owner, need data logging cable
« Reply #23 on: May 28, 2011, 07:50:04 PM »
In particular, it is usually the case that - if the console is powered up - unplugging the logger and plugging it back in will cause logging to cease until there is a complete power reset.

"Powered" in the above seems to mean "power available" (that is, including the batteries).   

This is good to know.   When I was sniffing the data interchange between the processor and the RF chip, I saw some other traffic just when the console was reset that I couldn't explain and that I didn't see afterward.  I now suspect that was the console trying to talk to the memory chip on the same "SPI" bus.  It got no answer back so it didn't try again afterward.

Wxtech, what package was the 45DB memory chip: the SOIC version with just eight pins?

Offline wxtech

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Re: New VP2 owner, need data logging cable
« Reply #24 on: May 28, 2011, 08:53:18 PM »
The package is soic.  The P/N looks like 450B011B but I couldn't match that with a part, so I settled on 45DB011B.  The top line is Atmel 0321 which is date 2003, 21st week.
Is this just a hobby or does anyone intend to build one?  I designed an anemometer replacement for the VP2 and no one built one.  No one seems to have electronics skills.  I think the Davis datalogger is a value priced item.  I'll build you one for $300.00.   
Al Washington, Lexington, Ga.,  NWS Coop station=LXTG1, Fischer Porter, SRG, MMTS. 
CoCoRaHS=GA-OG-1. CWOP=CW2074.  Davis VP2+ WLIP 5.9.2, VP(original) serial, VWS v15.00 p02. ImageSalsa, Win7 & Win8 all-in-one.

 

anything