MJLorton Solar Power and Electronic Measurement Equipment Forum
Youtube Video Episodes => YouTube Video Episodes => Topic started by: MJLorton on November 29, 2012, 11:44:33 PM
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Hi Folks,
All of Franky's inline power / watt meters arrived very quickly from Hong Kong.
Here is the video review: http://www.youtube.com/watch?v=cCd2DDoz38g
Below are some clips taken from the review. When Franky is ready he'll post some more details and pricing.
Cheers,
Martin.
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Regarding the pins and possibility of inserting it incorrectly, a drop of crazy glue on the non used receiver pin/hole is an easy cheap bodge.
PS. You must have dissed someone because I can't understand why you always get one dislike. He/she must have a grudge against you?
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Hi Martin,
Thank you for yet another interesting video.
I'm still watching it right now, (2nd meter almost done), but to me it seems that these meters have ADC's with insufficient resolution. This would be why even with a stable source voltage it jumps with ~6 counts.
Just out of curiosity, do you have the prices of these meters listed somewhere ? I'm wondering how the price/performance of these meters compares.
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Nice review Martin, as always!
Here are some instructions for calibrating the 3rd meter. It's not documented at all but I found these from a similar DIY kit and tried it myself and it worked.
1. Connect an accurate multimeter at the output end of the meter (the top 2 wires on the right) to measure voltage. Connect the variable power supply to the input wires (the bottom 2).
2. Hold that button on the left while you power up the meter. Release the button after a couple of seconds.
3. The screen shows 0V, make sure your power supply's output is turned off and the multimeter reads 0V.
4. Push the button again. The display now shows 2V.
5. Adjust the input voltage until the multimeter reads 2V.
6. Push the button again. Now the display shows 19V.
7. Adjust the input voltage until the multimeter reads 19V.
8. Push the button again. Now the display shows 0A.
9. Disconnect and reconnect the leads on the multimeter to the Amp range and switch to Amp measurement.
10 Switch off the power supply's output so the multimeter reads 0A.
11. Push the button again. Now the display shows 1.9A.
12. Adjust your power supply's current output until the multimeter reads 1.9A.
13. Push the button again. Done!
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As for pricing, the first 2 meters cost the same to me. You can find the SkyRC meter on eBay (other sellers) for just under $26 (without the temperature probe). I can just about offer the same price to members here, perhaps a buck or 2 less. Temperature probe will be an additional $4. The second meter will be priced the same (obviously it doesn't have the temperature option). However, at this point I'm still not sure I would even "sell" them as I just don't feel like they are worthy of the price given their performance. I do still have a few of those SkyRC's here so I might just go yard sale style to get rid of them :)
Now the 3rd meter actually costs only 1/3 of the price of the other 2. However, adding shipping and other costs the best that I can do is probably around $14 (shipping included) for forum members.
These prices are not final yet, but I just wanted to give people a rough idea first. I will be adding the 3rd meter in my eBay store next week.
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Hi Martin,
it will be nice if you can teardown these watt meter's, based on MCU ADC it easy to calculate real resolution. For example one with attiny26l have 10bit ADC so maximal resolution is only about 58mV for 60V range (Vrange/2^Nbits). So 3 or more digit after decimal point it's just impractical, unnecessary gadget.
Accuracy is basis on quality of parts used in voltage divider and quality of shunt resistor, cheap parts have significant temperature drift etc. Even if all resistors will be measured used 6.5 digit DMM and these values will be placed in EEPROM to increase measurements accuracy it's not possible to omit ADC resolution and variability under the influence of time and temperature.
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More information about the 3rd meter:
As far as I know this meter was designed and published by a Chinese electronics enthusiast some years ago and has since been made rather popular as DIY kits or semi-product in the Chinese market. After a little research I think I found his original website where he published the design: http://blog.21ic.com/user1/4577/archives/2007/43308.html It is all in Chinese but there's a schematic for those interested. In the article he also mentions something about how he's using the multiple differential ADC channels with the x1 and x20 gains to do the measurements and improve accuracy, etc. Unfortunately I don't have the technical expertise to understand or translate, but from what I gather he's doing something clever to improve accuracy and resolution meaningfully.
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Hey,
few min ago I have build this on a STK500 quickly. Software 40V/5A and a short ADC test. Without any Hardware. It is very easy to build, but under $US14 I can't competition with you.
btw u mean $US or Hongkong, Canadian, Australian, Bermuda Dollar ? The last four sounds much better for me :D
Here a few pics of my quick 'n dirty setup.
Sry for this bad quality. Its dark here and LCDs are not easy to shot.
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Nice job Fennec! Do you find the measurements accurate with your setup? EDIT: Just noticed you said there's no hardware, so I guess there wasn't any "real" measurement. But with your software test do you think the ADC is providing a real 3 decimal point resolution?
Oh, BTW, it was US$ I was talking about :)
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No, I only have checked the ADC if it works.
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@iloveelectronics - I would be interested in buying one of those un-cased Watt meters for $14 (I assume US$?)
Let me know how to pay etc.
Cheers
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@iloveelectronics - I would be interested in buying one of those un-cased Watt meters for $14 (I assume US$?)
Let me know how to pay etc.
Cheers
Thanks for the interest! This meter seems to be getting a lot of interest already, before I even put it up for sale at my eBay store!
I sent you a PM with my PayPal address. Please check.
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Maybe you can compare this one also.
http://www.hobbyking.com/hobbyking/store/__10080__Turnigy_130A_Watt_Meter_and_Power_Analyzer.html (http://www.hobbyking.com/hobbyking/store/__10080__Turnigy_130A_Watt_Meter_and_Power_Analyzer.html)
I use one for charging my electric bike and topping off cars batteries. I like it. Seems to show similar Ah reading compared to Cycle Analyst. One thing I don't like is the hard to read display. Got to look at it at the right angle. It has a backlight display.
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Regarding the pins and possibility of inserting it incorrectly, a drop of crazy glue on the non used receiver pin/hole is an easy cheap bodge.
PS. You must have dissed someone because I can't understand why you always get one dislike. He/she must have a grudge against you?
Thanks...good idea as I was thinking of ways to avoid that again.
Yup....not sure who or how I have dissed someone...
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Maybe you can compare this one also.
http://www.hobbyking.com/hobbyking/store/__10080__Turnigy_130A_Watt_Meter_and_Power_Analyzer.html (http://www.hobbyking.com/hobbyking/store/__10080__Turnigy_130A_Watt_Meter_and_Power_Analyzer.html)
I use one for charging my electric bike and topping off cars batteries. I like it. Seems to show similar Ah reading compared to Cycle Analyst. One thing I don't like is the hard to read display. Got to look at it at the right angle. It has a backlight display.
Not a bad idea, the Turnigy meter has caught my eye before....I'll see if I can get hold of one.
Thanks for the post.
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Hi Martin,
it will be nice if you can teardown these watt meter's, based on MCU ADC it easy to calculate real resolution. For example one with attiny26l have 10bit ADC so maximal resolution is only about 58mV for 60V range (Vrange/2^Nbits). So 3 or more digit after decimal point it's just impractical, unnecessary gadget.
Accuracy is basis on quality of parts used in voltage divider and quality of shunt resistor, cheap parts have significant temperature drift etc. Even if all resistors will be measured used 6.5 digit DMM and these values will be placed in EEPROM to increase measurements accuracy it's not possible to omit ADC resolution and variability under the influence of time and temperature.
Thanks for the input...let me try make some time for a look inside in the near future.
Cheers, Martin.
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I am also ready to go ahead and get the $14 Uncased Meter. If Franky is ready to sell Im ready to buy. My Email for PayPal address to send me is wyreless@gmail.com
Thanks Franky.
BTW, Hobby King has the TURNIGY 130 Amp Watt Meter equivalent to the WATTS UP for $23.95 and I was quoted at $5.99 for their International Airmail. So if you can get a hold of these and can match (or beat) that pricepoint, I know I'd rather give my money to one of Martins Preferred Vendors.
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I am also ready to go ahead and get the $14 Uncased Meter. If Franky is ready to sell Im ready to buy. My Email for PayPal address to send me is wyreless@gmail.com
Thanks Franky.
Yes, I'm always ready to sell :) The only thing is the meter doesn't come with any documentation or instructions and I was going to write something up, but I haven't got around doing that yet. If you don't mind referring back to Martin's video and also the calibration instructions on page 1 of this thread you are more than welcome to buy one. I'll send you a paypal money request shortly.
BTW, Hobby King has the TURNIGY 130 Amp Watt Meter equivalent to the WATTS UP for $23.95 and I was quoted at $5.99 for their International Airmail. So if you can get a hold of these and can match (or beat) that pricepoint, I know I'd rather give my money to one of Martins Preferred Vendors.
Unfortunately I don't have low cost access to the Turnigy meters, and that is one really low price to beat! However, I have found something that looks almost identical to it and I have ordered one and I will see if it offers the accuracy and resolution it claims. It is called the "G.T.Power 130A Watt Meter" http://www.youtube.com/watch?v=y7-iaxjqyOk. I must admit the $23.95 price is really hard to beat though even with this "clone"!
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For example one with attiny26l have 10bit ADC so maximal resolution is only about 58mV for 60V range (Vrange/2^Nbits). So 3 or more digit after decimal point it's just impractical, unnecessary gadget.
Not really. You can calculate with "fixed point arithmetic" and simple diplay, with a 10Bit ADC , maybe 10µV resulution.
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Just wanted to give a quick update on the status of the uncased watt meter that sold out quicker than I had time to even list it on eBay. The original supplier initially told me they couldn't source the bigger LCD at the price point they had, so they had to revise the design and change to a smaller (standard sized) LCD. I've been trying to follow up with them in the past weeks to see if I can get a bunch of the new meters when they become available again but unfortunately their latest response is that they have been flooded with other orders and have decided to discontinue this product :(
I have since tried to find similar kits/products and am in the process of evaluating a few alternatives. I actually just assembled a kit today which is based on the same schematics (different PCB design), but has an older firmware. It uses a DIP packaged (using socket) ATTiny26L so I should be able to upgrade the firmware myself, once I've learned how to do it :D
I'll post another update when I have found a viable alternative that works well.
It would also be nice to hear some feedback from those who have purchased the meter from me.
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Hi everyone, just reviving this old thread. Was wondering if Martin ever replaced the lcd in the uncased watt meter ???
I have just ordered one from Franky and a Watts Up from Martin's Amazon store. Franky is sending me an extra back-lit lcd and I am going to try and flash the firmware myself. Does any one know if PonyProg is compatible with the ATtiny26L ? I would assume it would be since it is with the ATtiny26, but I'm unsure what the L designates.
Would be interested in hearing from any one who has dabbled around with these kits, I see a lot of potential once we get things sused out in English :)
Thanks Franky!!!!
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Does any one know if PonyProg is compatible with the ATtiny26L ? I would assume it would be since it is with the ATtiny26, but I'm unsure what the L designates.
I think the L and non L versions only differ in the operating voltage: http://www.atmel.com/Images/doc1477.pdf
I don't know much about flashing firmware yet but I believe PonyPorg would work fine as the watt meter's designer's website has screenshot of the program: http://blog.21ic.com/user1/4577/archives/2007/43308.html#47474
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Thanks Franky,
Hopefully in a few weeks I'll be able to explain how to do it, but don't hold your breath :)
Thanks Franky, enjoy the holidays!!
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Does anyone know which of the three pins at the input side of the Po8er housing to use for plus and minus auxillary power?
I bought one of these on eBay, and it lacks the little connection cable for that.
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Does anyone know which of the three pins at the input side of the Po8er housing to use for plus and minus auxillary power?
I bought one of these on eBay, and it lacks the little connection cable for that.
What I found with mine was that the top pin is ground. Middle pin is for any positive voltage above about 7V, a 9V battery works well. I have no idea what the 3rd pin does.
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I had someone email and ask the same question. I sent this to him with the pictures.:
"The attached two photos show the auxiliary power is the top two pins (1st negative and 2nd positive). I believe if the 3rd pin is connected to negative (push button) it will reset the meter without having to disconnect the power. The voltage range is 4-60v DC."
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Hi all,
Does anyone know if there is a dialect of the Po8er design family (or any of the others in this video) , allowing it to measure and display not only OUTGOING Ampere, but also INCOMING.
Thus, the Ah readout would not only increase at consumption, but also decrease at charging.
This situation is common both for boats where Amps from solar charger and to gadgets is an ever changing battle. Another example is electric vehicles where electric regenerating braking is applied.
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Hi Timothy,
I have an in line power meter called the Medusa Power Analyzer Pro which does bi-directional measurements and I think does what you are asking...it even data logs with an added module. However...it is no longer produced...a pity.
You next best option unless someone else knows of another meter is a battery monitor...like the one I did a tutorial on for Victron: https://www.youtube.com/watch?v=JO8AGV4Z7K0
Cheers,
Martin.
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The victron typically sells for about 140 USD/pcs
The meters I look for are priced 15-30 USD/pcs
The closest found so far is this family of gadgets:
http://www.ebay.com/itm/90V-30A-Volt-Amp-Battery-Capacity-Power-Combo-Meter-Charge-Discharge-Indicator-/180956352800?pt=LH_DefaultDomain_0&hash=item2a21d6d120 (http://www.ebay.com/itm/90V-30A-Volt-Amp-Battery-Capacity-Power-Combo-Meter-Charge-Discharge-Indicator-/180956352800?pt=LH_DefaultDomain_0&hash=item2a21d6d120)
Admittedly, these simpler meters do not take the Peukert effect into account, but for i.e. use cases where it is frequently known when the battery bank is fully charged, the charge and discharge currents are low compared to the bank capacity, frequent resetting will do fine.
As you certainly know, the golden rule for good engineering is: Better reasonably right than exactly wrong.
Fiddling with battery aging and Peukert effect coefficients without resetting frequently is not better.....
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Finally an update on this :) I now know how to flash the new firmware into the chips so I'm ready to sell the watt meter kit I've mentioned months ago in the following post. I'll make another post later tonight in the buy/sell forum with some pictures. The kit will be priced at $14 (air mail shipping included with no tracking) for forum members.
Just wanted to give a quick update on the status of the uncased watt meter that sold out quicker than I had time to even list it on eBay. The original supplier initially told me they couldn't source the bigger LCD at the price point they had, so they had to revise the design and change to a smaller (standard sized) LCD. I've been trying to follow up with them in the past weeks to see if I can get a bunch of the new meters when they become available again but unfortunately their latest response is that they have been flooded with other orders and have decided to discontinue this product :(
I have since tried to find similar kits/products and am in the process of evaluating a few alternatives. I actually just assembled a kit today which is based on the same schematics (different PCB design), but has an older firmware. It uses a DIP packaged (using socket) ATTiny26L so I should be able to upgrade the firmware myself, once I've learned how to do it :D
I'll post another update when I have found a viable alternative that works well.
It would also be nice to hear some feedback from those who have purchased the meter from me.
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Finally an update on this :) I now know how to flash the new firmware into the chips so I'm ready to sell the watt meter kit I've mentioned months ago in the following post. I'll make another post later tonight in the buy/sell forum with some pictures. The kit will be priced at $14 (air mail shipping included with no tracking) for forum members.
Just wanted to give a quick update on the status of the uncased watt meter that sold out quicker than I had time to even list it on eBay. The original supplier initially told me they couldn't source the bigger LCD at the price point they had, so they had to revise the design and change to a smaller (standard sized) LCD. I've been trying to follow up with them in the past weeks to see if I can get a bunch of the new meters when they become available again but unfortunately their latest response is that they have been flooded with other orders and have decided to discontinue this product :(
I have since tried to find similar kits/products and am in the process of evaluating a few alternatives. I actually just assembled a kit today which is based on the same schematics (different PCB design), but has an older firmware. It uses a DIP packaged (using socket) ATTiny26L so I should be able to upgrade the firmware myself, once I've learned how to do it :D
I'll post another update when I have found a viable alternative that works well.
It would also be nice to hear some feedback from those who have purchased the meter from me.
I've ben talking with you, and know I'm waiting your buy/sell fórum post in order to make you an order (I will review the specs, just in case)
I think you are very responsable in your work and you show me that you are a good seller.
THANKS,
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Hi Martin
At the beginning I'd like to say hello all the way from Warsaw in Poland as I am a new fan of your videos. They are just great! Love not just what you tell an how yoy tell but allso the great neatnes and scruptulousity how you mount them. The picture quality, the appropriate lightning, all makes your videos just a pure pleasure to watch.
But let's get to the point. A few days before (a pitty) I discoverd the wideo of this thread I ordered form ebay a clone of the second meter in your film (Po8er). I,ve build DIY solar panel.Wish I had a fev pictures - maby if you'd like to see them I'll send them next time. Didn't care about the long time duration, however it is nicely encapsulated in electrotechnical sylicone. I' ve build it purely for my edycational purposes and to get my new hobby runing. It is about 6v and 2amps open circut. From your video I've discoverd that the Po8er power meter switches off without aux power just below 7v although the user manual (think it can be even seen on your video) says it don't require aux power even when supplyed with just over 4V. Now, it seems it won't work in my instalation without aux power. Sorry if it's a stupid question, but I'm totally new to electricity topics.
Can I split the wires coming from my solar panel and conect them to source and to aux?
And the second question: what type of plug is it that can be plugged into aux inlet in that meter - cause it seems I will have to buy it separately.
Just if you're interested the panel is to charge (project not finished yet) a 3,7 V battery through a small protection board (don't know yet but allso mayby through a LDO 5V voltage regulator. And then the 3,7 V battery will supply through a this step up converter :
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=141060955093
to which I will plug my mobile phone. So generally it is a mobile phone charger with some features build in like possibility to charge a phone during night time and a voltage regulation against both to high and to low voltage supply.
All the philosofy of this projest is to make it copletly standalone from any external power source. So it would really ruine my day if I had to use a simple AA or AAA batteries to supply the aux because the batteries would most probbably be charged from a grid socket. So what's the sense of making solar charger if you had to power the power meter controling it's performance with the electricity from your grid socket right? ;) (However on the second thought the aux could allso be supplyed with the 3,7v battery wich the solar panel first charges, can't it? But then I would have to use some step up converter because I see from your video that the minimum aux input voltage is 4V)
Anyway. Thanks again for GREAT videos
Best Regards
Konrad Hanc
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Hello Konrad,
Thanks for the feedback and great to hear you are having fun experimenting and building.
So to your question...don't worry about splitting the output from your solar panel to the aux....if there's enough voltage / power from the solar it will power up....and connecting to the Aux won't help.
The plugs that will fit are the JST 2 or 3 pin types:
http://www.amazon.com/Gino-Remote-Control-Servo-Extension/dp/B007SUKUXM/ref=pd_sim_sbs_hi_3
http://www.amazon.com/pairs-Plug-Connector-Battery-Female/dp/B0089RAXB2/ref=pd_sim_sbs_hi_6
I'm afraid it's going to be a challenge using that meter and keeping it powered from the battery without an AC adapter...
Are you using it to read power or just the voltage?
Martin.
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Hi Martin
Great thanks for your response. I know you're busy.
I'm still waiting for the power meter to arrive. I was hoping to use it for power reading. Do you think using a 3,7V Li-ion or Li-Polymer polymer with step up converter to lets say 7v won't work? Why? Is it because the power meter uses so much power itself that it would drain the battery fast? Or is it for some other reason? I will post my progress in Solads. Power part of your forum in birrbert's thread as we are making exactly the same project and exchanging experiences:)
Best regards.
Konrad Hanc
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Hi Konrad,
It will work. My meter needs 7.8 volt at 9 mA to operate. So that means 216 mAh per day. If you need to use a DC-DC converter you'll have to more than double that figure so it'll be more like 500 mAh per day...so if left on permanently adds up fast.
Hope that helps.
Cheers,
Martin.
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Hi Martin,
Thanks for the review of these in-line watt meters. I wish I bumped to your review before I bought one of them.
During your review, have you ever measured the accuracy of the actual Ah and Wh reading? I bought the 150A watt meter (I bought this from eBay, but the product is exactly like http://www.dragonrc.com.au/150A-High-Precision-Watt-Meter-and-Power-Analyser-p/sftrc-wm150a.htm (http://www.dragonrc.com.au/150A-High-Precision-Watt-Meter-and-Power-Analyser-p/sftrc-wm150a.htm)), and having major problem with the Ah and Wh readings.
The problem is my Ah and Wh does not compute properly, i.e. it actually goes backwards :o (instead of accumulating) when the output current drops. It also resets to '0' if the load goes to 0A. I wonder whether this problem pertinent to this model (150A), or just my batch.
Background: I was too stingy to get a proper MPPT lithium-ion charger (like the one made by Genasun), but using cheap CC-CV converter with Wh meter to monitor my e-Bike battery charging instead (using solar panel).
Your review confirms my finding of the inaccuracy of these units ('high precision' label does mean nothing). Lucky I did some test first before I start charging my Lithium pack.
Again, thanks heaps for your time.
Rusdy
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Hi Rusdy,
Thanks for the feedback, I'm glad the review was helpful.
You raise a good question about measuring the actual consumption figures as a check. There are certainly ways I could do it with the equipment I have.
I would however like to find a good device that directly measures power consumption (Wh and Ah) accurately. Not too many about for DC.
Cheers,
Martin.
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Nice review Martin, as always!
Now: What is that, this "surprise-O-meter" and how can I get one?
really interested ... but sofar no hint where you can find it!
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Nice review Martin, as always!
Now: What is that, this "surprise-O-meter" and how can I get one?
really interested ... but sofar no hint where you can find it!
http://mjlorton.com/forum/index.php?topic=288.0