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MEMS L3G4200D, by ST microelectronics, three axis gyro scopefor satellite dish alignment.
Are the micro electrical mechanical systems (MEMS) three axis, yaw, pitch and roll accuracy good enough to align a C or Ku bandsatellite dish? I will experiment with the L3G4200d gyro one I get the backordered circuit development board; it may be a month or more from now. Briefly,the L3G4200D gyro is ultra-stable three-axis digital output gyroscope with 16 bit-ratevalue data output.The L3G4200D gyro is the same deviceas found in the Apple iPad 2 and Samsung's Android based Galaxy tablet. Gyro compasses, yaw pitch and roll display has already been incorporated into "APPS"for these devices. Answers have been found, but virtually no documentation exists on details. In the hopes of gaining insight to the ST gyro, I pose thequestion in a group where dish alignment is often discussed. What I desire fromthe L3G2400D gyro is:
1. North seeking capability. This may take hours to complete, but the results hould provide high accuracy to establish true North without using a magnetic compass or GPS receiver. Accuracy should be better that one degree. My main problem is establishing due south within a degree or better. As simple as this sounds, it is nearly impossible without fancy surveying equipment. A magnetic compass is useless. Its accuracy is thrown off by the dish's metallic effect,even accounting for magnetic declination correction. A true north seeking gyro will provide a true reading, independent of metallic effect, and is easy toapply to the dish alignment result.
2. The L3G4200D must be capable of replacing traditional rotary encoders for motion control. It really simplifies mechanical design when asmall gyro can replace a rotary encoder. In this case the size of the L2G4200Dis 4x4 mm. Compare this size with a typical rotary encoder of over an inch in diameter or larger. Well may not be fair, the L3G4200D needs to be supported bya local CPU and support circuitry that also may exceed a one inch size, but is not dependent on the same constraints required for a rotary encoder's mounting requirements. There is more freedom with a gyro than a rotary encoder mounting requirements.
The L3G4200D three axis gyro is a rate device. It outputs to the external world degrees/second for yaw, pitch and roll. I need to convert the rate output values to position or degrees. A simple integrator will provide the conversion, however the time between reads must be precisely known. I do not know the best way of configuration the L3G4200D or the best time clock to use. I know windows supports a high performance clock mode with microsecond precision (and have used it often), but it's also affected by time to interrupt delay and other OS overhead. Ideally the L3G4200D gyro should provide a time stamp synchronized to the actual time of data capture.
For the L3G4200D, the basic concept is simple to understand; however, the details are difficult to unravel and understand. The most time is spent on the details, not the concept.
Ok back up! What the hell is this nut case trying to accomplish.
Ideally I am trying to replace the actuator pulse count with a rotary optical encoder mounted at the dish's axis of rotation. This is same axis found in HH motors for USALS motion. Using an optical encoder at the dish rotational axis can provide USALS capability even though actuator driven. Take this one step further; the optical encoder can be replaced by a MEMS gyroscope. The result is a polar mount structure than can be improved by a simple MEMS gyroscope. Use the actuator for C band dishes, its strong, rugged and dependable. But, use the MEMS gyro for precise control. Forget about the actuator pulse count; use the output from MEMs gyro for precise PID motion control. Even forget about modified declination tilt, use a small second actuator to provide exact tilt declination per satellite position using the MEMS gyro output. Only one axis is needed, but a second axis will provide conformation.
Sorry for being long winded, however this application has caught my attention with a fury.
I dream of the day when I can get my 6 foot dish aligned and tracking. So far only dismal results have been achieved. OH! My mounting poleis vertical from the ground, I have checked it many, many times using a level and two different types of digital levels; it is correct as well as all otheralignments. However there must be a mistake and I feel only more exotic methods will finally shed some light where the miss alignment is. Part of the problem is the extreme sloppy alignment method for aligning the C/Ku band LNB. Just a set screw? He guys, there must be a better method. Maybe a MEMS Gyro mounted onthe C/Ku band LNB will enable alignment. Watcha you think? Sorry for sarcasm,but when you have spent hours for only dismal results you have got to be annoyed.
Suggestions, corrections, criticisms, even flames are allappreciated.
Rob
Are the micro electrical mechanical systems (MEMS) three axis, yaw, pitch and roll accuracy good enough to align a C or Ku bandsatellite dish? I will experiment with the L3G4200d gyro one I get the backordered circuit development board; it may be a month or more from now. Briefly,the L3G4200D gyro is ultra-stable three-axis digital output gyroscope with 16 bit-ratevalue data output.The L3G4200D gyro is the same deviceas found in the Apple iPad 2 and Samsung's Android based Galaxy tablet. Gyro compasses, yaw pitch and roll display has already been incorporated into "APPS"for these devices. Answers have been found, but virtually no documentation exists on details. In the hopes of gaining insight to the ST gyro, I pose thequestion in a group where dish alignment is often discussed. What I desire fromthe L3G2400D gyro is:
1. North seeking capability. This may take hours to complete, but the results hould provide high accuracy to establish true North without using a magnetic compass or GPS receiver. Accuracy should be better that one degree. My main problem is establishing due south within a degree or better. As simple as this sounds, it is nearly impossible without fancy surveying equipment. A magnetic compass is useless. Its accuracy is thrown off by the dish's metallic effect,even accounting for magnetic declination correction. A true north seeking gyro will provide a true reading, independent of metallic effect, and is easy toapply to the dish alignment result.
2. The L3G4200D must be capable of replacing traditional rotary encoders for motion control. It really simplifies mechanical design when asmall gyro can replace a rotary encoder. In this case the size of the L2G4200Dis 4x4 mm. Compare this size with a typical rotary encoder of over an inch in diameter or larger. Well may not be fair, the L3G4200D needs to be supported bya local CPU and support circuitry that also may exceed a one inch size, but is not dependent on the same constraints required for a rotary encoder's mounting requirements. There is more freedom with a gyro than a rotary encoder mounting requirements.
The L3G4200D three axis gyro is a rate device. It outputs to the external world degrees/second for yaw, pitch and roll. I need to convert the rate output values to position or degrees. A simple integrator will provide the conversion, however the time between reads must be precisely known. I do not know the best way of configuration the L3G4200D or the best time clock to use. I know windows supports a high performance clock mode with microsecond precision (and have used it often), but it's also affected by time to interrupt delay and other OS overhead. Ideally the L3G4200D gyro should provide a time stamp synchronized to the actual time of data capture.
For the L3G4200D, the basic concept is simple to understand; however, the details are difficult to unravel and understand. The most time is spent on the details, not the concept.
Ok back up! What the hell is this nut case trying to accomplish.
Ideally I am trying to replace the actuator pulse count with a rotary optical encoder mounted at the dish's axis of rotation. This is same axis found in HH motors for USALS motion. Using an optical encoder at the dish rotational axis can provide USALS capability even though actuator driven. Take this one step further; the optical encoder can be replaced by a MEMS gyroscope. The result is a polar mount structure than can be improved by a simple MEMS gyroscope. Use the actuator for C band dishes, its strong, rugged and dependable. But, use the MEMS gyro for precise control. Forget about the actuator pulse count; use the output from MEMs gyro for precise PID motion control. Even forget about modified declination tilt, use a small second actuator to provide exact tilt declination per satellite position using the MEMS gyro output. Only one axis is needed, but a second axis will provide conformation.
Sorry for being long winded, however this application has caught my attention with a fury.
I dream of the day when I can get my 6 foot dish aligned and tracking. So far only dismal results have been achieved. OH! My mounting poleis vertical from the ground, I have checked it many, many times using a level and two different types of digital levels; it is correct as well as all otheralignments. However there must be a mistake and I feel only more exotic methods will finally shed some light where the miss alignment is. Part of the problem is the extreme sloppy alignment method for aligning the C/Ku band LNB. Just a set screw? He guys, there must be a better method. Maybe a MEMS Gyro mounted onthe C/Ku band LNB will enable alignment. Watcha you think? Sorry for sarcasm,but when you have spent hours for only dismal results you have got to be annoyed.
Suggestions, corrections, criticisms, even flames are allappreciated.
Rob
7 Replies
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3979 views
Other people have been able to align their 6' dishes.
... with regular common tools, and a bit of patience.
Yes, some of the one-screw scalars are unfriendly.
I added a little metal bracket/tab to mine, and filed the tip of the screw flat.
Expecting a pile of uncalibrated, unaligned, hardware to suddenly find the magic signal,
is a bit unlikely.
You might as well build signal-hunting into this robo-dish.
There is a company who makes the Arc-Set alignment tool.
You might want to invest in one of those.
Personally, I think it's overpriced snake oil, but that's just my opinion.
Search the forum for some recent (2011) discussion on the device.
The one interesting idea, is the use of a gyro for position feedback on a dish.
Not sure what happens when you loose power, though.
Maybe some brainstorming on the matter would prove fruitful. (?)
Or at least fanciful.
The thing is, I found a rotary shaft encoder for a reasonable price, with around 2000 counts per revolution.
At the time, I dismissed it for a hand full of reasons... most of which apply to a gyro as well.
At least, the shaft encoder would have been a lot less trouble to install and operate. :up
... with regular common tools, and a bit of patience.
Yes, some of the one-screw scalars are unfriendly.
I added a little metal bracket/tab to mine, and filed the tip of the screw flat.
Expecting a pile of uncalibrated, unaligned, hardware to suddenly find the magic signal,
is a bit unlikely.
You might as well build signal-hunting into this robo-dish.
There is a company who makes the Arc-Set alignment tool.
You might want to invest in one of those.
Personally, I think it's overpriced snake oil, but that's just my opinion.
Search the forum for some recent (2011) discussion on the device.
The one interesting idea, is the use of a gyro for position feedback on a dish.
Not sure what happens when you loose power, though.
Maybe some brainstorming on the matter would prove fruitful. (?)
Or at least fanciful.
The thing is, I found a rotary shaft encoder for a reasonable price, with around 2000 counts per revolution.
At the time, I dismissed it for a hand full of reasons... most of which apply to a gyro as well.
At least, the shaft encoder would have been a lot less trouble to install and operate. :up
R
Thank you for your comments.
It's the problem and the journey to find a solution I find interesting. I know others can get their dish aligned without too much fuss using ordinary tools. However I prefer as you say "robo-dish" alignment
Losing power is no different than losing power with an actuator system. The G-BOX will maintain the position count. The same is true for a GYRO or rotary shaft encoder. The control box could be a G-Box or a custom designed one for enhanced features; USALS for instance, would be nice.
Thank you for your comments.
It's the problem and the journey to find a solution I find interesting. I know others can get their dish aligned without too much fuss using ordinary tools. However I prefer as you say "robo-dish" alignment
Losing power is no different than losing power with an actuator system. The G-BOX will maintain the position count. The same is true for a GYRO or rotary shaft encoder. The control box could be a G-Box or a custom designed one for enhanced features; USALS for instance, would be nice.
I have Dish with Hopper3. I choose to get local channels OTA and had a "guide list" established at my previous home. Having moved a few miles away, I wanted to update the list by appending a couple new stations via a rescan. As many would know, some stations come in with the UHF/VHF antenna aimed in one direction, while others come in better with a different direction.
Unfortunately, when a scan is done (bringing in 25-30 stations for that particular antenna aim), the dialog screen does not present the established guide list; it presents an empty field to the right that the scanned stations may be selected one by one and added to the empty guide. But because of antenna aim, some stations originally saved are missing, and would have to be retrieved with a different antenna aim. But as I explain, if a 2nd scan is done with a different antenna aim, the stations saved from the first scan are lost.
It troubles me that Dish didn't develop software that would allow a user to simply append only 1 or 2 channels to the established list.
Any thought on this? Has anyone experienced this or heard of this from others?
Unfortunately, when a scan is done (bringing in 25-30 stations for that particular antenna aim), the dialog screen does not present the established guide list; it presents an empty field to the right that the scanned stations may be selected one by one and added to the empty guide. But because of antenna aim, some stations originally saved are missing, and would have to be retrieved with a different antenna aim. But as I explain, if a 2nd scan is done with a different antenna aim, the stations saved from the first scan are lost.
It troubles me that Dish didn't develop software that would allow a user to simply append only 1 or 2 channels to the established list.
Any thought on this? Has anyone experienced this or heard of this from others?
13 Replies
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469 views
Pub Member / Supporter
12 Replies
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244 views
Apparently I'm not a big enough nerd
since I did not read every Marvel Comic Book ever published. If I had, I might be comparing the comics' version of events compared to what's transpiring in "Visionquest". So, I am enjoying the series a lot, not weighed down by previous expectations, knowing only the Avengers MCU movies and the "Wandavision" / "Agatha All Along" TV series.
I found the Mr Know-it-All channel from his discussion about "Star Trek: Strange New Worlds" and he's been gleefully picking these episodes apart, referencing the Marvel comics from the 1939 on. Turns out A.I. has been around since before World War II, at least in the comics. (Robots before that, yes, yes.) This show is going back into the archives.
since I did not read every Marvel Comic Book ever published. If I had, I might be comparing the comics' version of events compared to what's transpiring in "Visionquest". So, I am enjoying the series a lot, not weighed down by previous expectations, knowing only the Avengers MCU movies and the "Wandavision" / "Agatha All Along" TV series.I found the Mr Know-it-All channel from his discussion about "Star Trek: Strange New Worlds" and he's been gleefully picking these episodes apart, referencing the Marvel comics from the 1939 on. Turns out A.I. has been around since before World War II, at least in the comics. (Robots before that, yes, yes.) This show is going back into the archives.
I thought they were effectively releasing a longer episode 7 and 8 instead of shorter episodes 7 & 8 this week and 9 & 10 next week. It felt like they were packing more into this episode.
edit: But you're right, the run time of the first three pairs of episodes was 100 minutes on average. Episode 7 clocks in at 65 minutes.
Staff member
HERE TO HELP YOU!
Cutting Edge
Sometimes a thread gets so many posts in it that is can cause issues for the server so that why today we introduce The Song Name Game Part 3!
So let the game continue!
The last song was added by Bobby who posted...
One Meat Ball - Andrews Sisters
CONTINUE ON AND HAVE FUN! WELCOME HOME TO SATELLITEGUYS.US!
Here are the original rules for the game as posted by WebbyDude back in 2006. http://www.satelliteguys.us/threads/68645-Song-Name-Game
Just name a song title and the band who performed it. The next person does the same thing, but needs to list a song title or band name which includes a word from the previous entry. Pick songs from any genre.
Example:
Long Live Rock and Roll -- Rainbow
Rainbow in the Dark -- Dio
Another example:
Ride the Lightning -- Metallica
Lightning Strikes -- Ozzy Osbourne
Get it?
An additional note: we all know that song titles, sometimes, use profane words. Because this is a family friendly website it is advised that you clean up that title up a bit. This is accomplished by using something like sh!t instead of the real word. Thanks....
So let the game continue!
The last song was added by Bobby who posted...
One Meat Ball - Andrews Sisters
CONTINUE ON AND HAVE FUN! WELCOME HOME TO SATELLITEGUYS.US!
Here are the original rules for the game as posted by WebbyDude back in 2006. http://www.satelliteguys.us/threads/68645-Song-Name-Game
Just name a song title and the band who performed it. The next person does the same thing, but needs to list a song title or band name which includes a word from the previous entry. Pick songs from any genre.
Example:
Long Live Rock and Roll -- Rainbow
Rainbow in the Dark -- Dio
Another example:
Ride the Lightning -- Metallica
Lightning Strikes -- Ozzy Osbourne
Get it?
An additional note: we all know that song titles, sometimes, use profane words. Because this is a family friendly website it is advised that you clean up that title up a bit. This is accomplished by using something like sh!t instead of the real word. Thanks....
68756 Replies
·
2684849 views
Staff member
HERE TO HELP YOU!
Cutting Edge
The following is from Reddit. -
View: https://www.reddit.com/r/DirectvStream/s/orzHBkmqQW
There appears to be a new DIRECTV Gemini OTT box, the C81KW-650.
The FCC listing is partially available, and a Geekbench entry confirms it uses an Amlogic S905X5, a solid SoC for a set-top box.
I also see 4GB of RAM, and the manufacturer is SEI Robotics.
DIRECTV C81KW OTT Box - Android TV Guide
Ok found a picture of the Box too on Reddit:
View: https://www.reddit.com/r/DirectvStream/comments/1twlex0/comment/opzeqi1/
View: https://www.reddit.com/r/DirectvStream/s/orzHBkmqQW
There appears to be a new DIRECTV Gemini OTT box, the C81KW-650.
The FCC listing is partially available, and a Geekbench entry confirms it uses an Amlogic S905X5, a solid SoC for a set-top box.
I also see 4GB of RAM, and the manufacturer is SEI Robotics.
DIRECTV C81KW OTT Box - Android TV Guide
Ok found a picture of the Box too on Reddit:
View: https://www.reddit.com/r/DirectvStream/comments/1twlex0/comment/opzeqi1/
25 Replies
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1380 views
iJustine
Time for another AWESOME video from iJustine!
View: https://www.youtube.com/shorts/LQT8wzemsLU
Direct YouTube Link - New (OLD?) Sony Walkman Headphones! MDR-3R!
The official iJustine Website's Website
Buy her book!
View: https://www.youtube.com/shorts/LQT8wzemsLU
Direct YouTube Link - New (OLD?) Sony Walkman Headphones! MDR-3R!
The official iJustine Website's Website
Buy her book!
0 Replies
·
9 views
Staff member
Pub Member / Supporter
Cutting Edge
The TPN Map Excel Presents all DIRECTV Channels:
Understanding the TPN Map
Making Sense of the TPN Map Display Conventions
National (50-States or wide/NAT+PR beams)
Local (Local-Into-Local or narrow/Spot beams)
Local (Local-Into-Local or narrow/Spot beams)
Additional tabs provide:
OTA the (Over-The-Air) Database
VOD (Video On_Demand) Records
Offline Records
Engr Records
Net Decoder a graphic presentation of all satellites and transponders
VOD (Video On_Demand) Records
Offline Records
Engr Records
Net Decoder a graphic presentation of all satellites and transponders
Domestic Satellites
@99W...... D11, D14
@101W.... D16
@103W.... D12, D15
@110W.... D5
@119W.... D8
@99W...... D11, D14
@101W.... D16
@103W.... D12, D15
@110W.... D5
@119W.... D8
Understanding the TPN Map
Making Sense of the TPN Map Display Conventions
2178 Replies
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952746 views
iJustine
Time for another AWESOME video from iJustine!
View: https://www.youtube.com/shorts/IxhDzSdSxZo
Direct YouTube Link - New LIGHT UP Apple Logo!
The official iJustine Website's Website
Buy her book!
View: https://www.youtube.com/shorts/IxhDzSdSxZo
Direct YouTube Link - New LIGHT UP Apple Logo!
The official iJustine Website's Website
Buy her book!
0 Replies
·
13 views
TWiT Tech Podcast Network
Time for another AWESOME video from the TWIT Network!
View: https://www.youtube.com/watch?v=bYMNztkdF6I
Direct YouTube Link - Tech News Weekly 462
TWIT's Website
TWIT Live Feed
View: https://www.youtube.com/watch?v=bYMNztkdF6I
Direct YouTube Link - Tech News Weekly 462
TWIT's Website
TWIT Live Feed
0 Replies
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12 views
Linus Tech Tips
Time for another AWESOME video from Linus Tech Tips!
View: https://www.youtube.com/watch?v=Ao9IQyaH0fk
Direct YouTube Link - "Tesla Hater" Finally Tries Full Self Driving
Linus on Facebook
The LTT Store
View: https://www.youtube.com/watch?v=Ao9IQyaH0fk
Direct YouTube Link - "Tesla Hater" Finally Tries Full Self Driving
Linus on Facebook
The LTT Store
0 Replies
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14 views
Lifetime Supporter
Looks like dish is Bankrupt. Filling tomorrow Tuesday June 30th
451 Replies
·
15477 views
Can't remember where or who I saw predict this.
It wouldn't surprise me to see Elon soon own all of DISH / Echostar in the future.
SpaceX boldly goes into 'huge' 5G network rollout with Qualcomm
After trying satellites and small cells, Elon Musk's SpaceX is to build a terrestrial mobile network across tens of thousands of sites with Qualcomm.
www.lightreading.com
M
Is Dish like Iran in one way...they both will totally collapse by end of week
