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Old May 24, 2011, 11:20 PM
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Leader Hobby GY520 MEMS Gyro

Received this gyro from Leader Hobby yesterday:
http://www.leaderhobby.com/product.asp?ID=9394001220733

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It boasts that it is a MEMS PID fuzzy logic gyro. Analog and digital servo support. It cost me $12.50 + shipping, on sale.

Update: Uses the InvenSense ISZ-650 MEMS sensor

There are no labels on the plastic case. The display is a single tri-color LED, which is clearly seen through the plastic case, when lit.

Manual:
http://www.leaderhobby.com/img/menu/GY520Manual.pdf

HX900 manual: (easier to understand, thanks to monkeyhanger)
http://queenhobby.com/imageupload/3661/HX900Manual.pdf

It's about the same size as the Turnigy Mini MEMS gyro. It uses the conventional two plugs for the receiver and a shorter flying lead for the servo. The wires are a good size and look to be strong. The Gain plug has two sockets in it even though only one wire is connected. This helps to stop the plug from falling out.

Unfortunately there was no mounting hardware supplied.

Picture of inside:
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Some components appear to be hand soldered. The MEMS sensor appears to be on the bottom covered in black silicone.

When I opened the case the board was not level in the case, and needed to be pressed in further. I will be gluing the board in with E6000 and adding E6000 to the wire solder joints.

On the bench the gyro appears to work well.

Note:
- Make sure your rudder EPAs are set to 100 or higher and you dual rates are at 100% before attempting to program the gyro.
- Leave the tail servo disconnected until servo type has been set. The default is digital 1520us 280Hz.
- Leave the tail control pushrod disconnected until each limit is set.
- If you can't get into programming mode, try setting the rudder trim to full in the direction you are pushing and holding the stick. This is known to fix a problem with the Walkera TX2603 getting into program mode.

- The yellow parameter color is not obvious. It's more of a green with a touch of red.
- Option 3 is set to 1 by default (not 3, as stated in the manual). I was surprised 3 and 4 were not the other way around (3 = 3 and 4 = 1), especially with it defaulting to a digital servo.
- Don't be fooled by the pause in the parameter value flash. There is a longer off period for the end of value, as opposed to the pause after every two counts (see page 9 of the manual).

The manual is quite hard to read. Here are some simplified programming instructions.

Programming:
- In rate mode (green led) hold the rudder stick at full right or left until the LED turns red, and then release quickly to center. This is option 1 (Servo type).
- The LED will flash the parameter value (i.e. -- -- - is 5). The default for the servo type is 2 flashes (1520us 280Hz).
- Push the rudder stick a short distance to the right or left (under half) and return to center, to change the parameter value. Check the flash count.
- Hold the rudder stick at full right or left to change to the next parameter and release to center. If the previous value was changed it will be saved. Holding the rudder at full right or left, will cycle through the parameters at a fast rate.
- To exit program mode switch to heading hold mode or move to a new parameter and power down the gyro.

Note:
- When the left or right limit parameter is reached, the first time, the servo goes to full travel. Make sure your pushrod is disconnected, until you have both the left and right limit lowered. The limit cannot be changed quickly and may damage your servo
- To adjust the limit parameter, push the rudder stick a short distance to the right or left (under half) and return to center. The servo will move a fixed step, each time this is done.
- Subtrim can be used with this gyro to center the servo. It will learn the new center at switch on.
- The gyro will not initialize until it sees servo data from the Rx.

Videos:
Setup video (thanks to Rob2160): http://www.rcgroups.com/forums/showp...&postcount=230
250 flight: http://www.rcgroups.com/forums/showp...&postcount=165
250 flight (thanks sp00fman): http://www.rcgroups.com/forums/showp...&postcount=360
450 flight (thanks sgbfly): http://www.rcgroups.com/forums/showp...&postcount=200
450 flight (thanks Rob2160): http://www.rcgroups.com/forums/showp...&postcount=225
450 flight (thanks sp00fman): http://www.rcgroups.com/forums/showp...&postcount=356
450 flight (thanks Arey): http://www.rcgroups.com/forums/showp...&postcount=370
450 flight (thanks sp00fman): http://www.rcgroups.com/forums/showp...&postcount=459

My settings:
250
1 = 760us 560Hz (DS95i)
2 = Normal
3 = 2 (direction speed)
4 = 1 (delay)
Rudder dual rates (L:55%, R:65%)
Expo 15%
Gain 24
7mm ball position
40mm blades
Tail pitch slider has full travel

450
1 = 1520us 280Hz (D261HB)
2 = Reverse
3 = 3 (direction speed)
4 = 1 (delay)
Expo 40%
Gain 32
10mm ball position (recommend starting with 7-8mm)
Pro tail blades
Tail pitch slider has full travel


Testing will be on a HK450 V2 with pro head and belt pro tail. The tail servo is an Ino-Lab HG D261HB with a 10mm ball position. Currently the tail is rock solid with a GP780.

Test mount:
----------- Single sided foam
======= metal plate
-- ....... -- Two strips of double sided foam (Velcro strap goes through here)
======= metal plate
----------- double sided foam

The gyro will be strapped to the 1/16 single sided foam on the top, which will allow quick removal, for testing other gyros.

ebay link (USD$14.48 + ship):
http://cgi.ebay.com/GY520-Head-Lock-...item2312981330

Also sold as a FMT-40 from FMT Model:
http://www.ebay.com/itm/F01874-FMT-4...-/270818131078

Now appears to be sold as a Tarot GY550, with a nice thin case, but more expensive:
http://www.rcgroups.com/forums/showt...2#post19333112
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Last edited by beenflying; Nov 18, 2011 at 03:34 AM.
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Old May 24, 2011, 11:35 PM
OlliW
Joined Sep 2009
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Hey beenflying,

very interesting, thanks for the report.

I would be most interested about learning a bit more about the hardware. You said, "The MEMS sensor appears to be on the bottom covered in black silicone.", not sure how to interpret that, I would have thought that the "black square" in the left corner in your picture would be the MEMS sensor (looks like an Invensense). Could you take two closer-up photos from both sides of the print board?

Olli

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Old May 24, 2011, 11:49 PM
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I assumed the top chip was the MPU, since the bottom chip (similar size), had the silicon. The top chip's number is too hard to read, even with a 7x loop. I suspect there would be nothing more to see in the pictures.
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Old May 25, 2011, 12:20 AM
OlliW
Joined Sep 2009
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thx for your quick reply

"The top chip's number is too hard to read, even with a 7x loop. I suspect there would be nothing more to see in the pictures."
maybe not the numbers, but often the layout around a chip tells a lot about the chip...

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Old May 25, 2011, 12:25 AM
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Quote:
Originally Posted by OlliW View Post
thx for your quick reply

"The top chip's number is too hard to read, even with a 7x loop. I suspect there would be nothing more to see in the pictures."
maybe not the numbers, but often the layout around a chip tells a lot about the chip...

___________
www.olliw.eu
I'll see what i can do.

FYI, someone on Leader Hobbies site has already said this:
Quote:
this is a cheapest gyro with a MEMS-sensor (Invensense ISZ-650)! very, very interesting.
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Old May 25, 2011, 12:47 AM
OlliW
Joined Sep 2009
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Quote:
I'll see what i can do.
cool, thanks

Quote:
this is a cheapest gyro with a MEMS-sensor (Invensense ISZ-650)! very, very interesting.
ahh... thanks a lot for this info...

but it's then NOT the cheapest MEMS gyro, and not the cheapest with a ISZ-650...
... the GA250 is significantly cheaper and it also uses an ISZ-650:
http://www.olliw.eu/uploads/gyro-GA250-withanno-wp.jpg
http://www.olliw.eu/uploads/gyro-GA250-circuit.png



Thx, Olli

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Old May 25, 2011, 01:08 AM
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Yeah I know that, but the GA250 also has some major flaws. I know from experience.

Even ASSAN is now admitting the GA-250 is just for beginners.

Edit: Seven dollars is hardly "significantly more", when it comes to the price of gyros, especially if it gives someone a gyro solution that will take them further.
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Old May 25, 2011, 01:10 AM
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Nice work by the way olliW in identifying the components and doing the schematic. What is your final purpose in this?
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Old May 25, 2011, 09:13 AM
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Quote:
Originally Posted by beenflying View Post
Yeah I know that, but the GA250 also has some major flaws. I know from experience.

Even ASSAN is now admitting the GA-250 is just for beginners.
What flaws have you found with the GA-250?

Quote:
Originally Posted by beenflying View Post
It boasts that it is a MEMS PID fuzzy logic gyro.
I feel like most days my logic is pretty fuzzy too!
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Old May 25, 2011, 11:36 AM
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Originally Posted by mountainsax View Post
What flaws have you found with the GA-250?
well here is one major flaw that deters me from going with assan until this can be resolved and brian is no beginner either although in the vid flying was just regular so in this case 50 bucks is NOT "significantly more"



ASSAN GA-250 Wag of Death and Crash - HK-250GT (1 min 0 sec)
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Old May 25, 2011, 12:16 PM
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>well here is one major flaw that deters me from going with assan until this can be resolved and brian is no beginner either although in the vid flying was just regular so in this case 50 bucks is NOT "significantly more"

If you read the Spartan groups, there's no shortage of people having exactly the same issues with those gyros. It's not a gyro problem, it's just that tail setup on a 250 is very very finicky. I had exactly the same sort of wag when I first got my GA250, but kept playing around with the gain until I got it just right. A change of 2 or 3% in gyro gain can make all the difference.
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Old May 25, 2011, 12:56 PM
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The Assan gyro is flawed because they are doing a public Alpha test with the GA-250.


I am very interested in these new alternative gyro's.
On what helicopters are you planning to test this one?
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Old May 25, 2011, 01:26 PM
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Quote:
Originally Posted by sp00fman View Post
The Assan gyro is flawed because they are doing a public Alpha test with the GA-250.


I am very interested in these new alternative gyro's.
On what helicopters are you planning to test this one?
If its a public alpha test then its pretty good

My GA-250 has held alot better than I could ever get my Hk401B to hold. And huess what its cheaper with no drift. how can you complain about a gyro that costs $10 and when setup correctly has no problems with the "Wag Of Death"
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Old May 25, 2011, 03:28 PM
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Quote:
Originally Posted by mountainsax View Post
What flaws have you found with the GA-250?
I flew the GA-250 on the two 450's, one from the first batch and one from the second batch. The GA-250 had stop problems on both heli's and on one heli, the servo fried (one I've been using for some time on two other heli's). I ran some servo temperature tests and the GA-250 was the hardest on the servos. I fitted GP780's to both of these heli's and they now fly perfectly.

The GA-250 is also known to blow out on reverse flight, something that will definitely cause a novice to crash, when they get in trouble.

Anyway this thread is about the Leader Hobby GY520. There is another thread for the GA-250.
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Old May 25, 2011, 03:29 PM
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Quote:
Originally Posted by sp00fman View Post
...I am very interested in these new alternative gyro's.
On what helicopters are you planning to test this one?
Bottom of the first post:
Quote:
Originally Posted by beenflying View Post
Testing will be on a HK450 V2 with pro head and belt pro tail. The tail servo is an Ino-Lab HG D261HB with a 10mm ball position. Currently the tail is rock solid with a GP780.

Test mount:
----------- Single sided foam
====== metal plate
-- ....... -- Two strips of double sided foam (Velcro strap goes through here)
====== metal plate
----------- double sided foam

The gyro will be strapped to the 1/16 single sided foam on the top, which will allow quick removal, for testing other gyros.
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