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Old Mar 01, 2008, 03:23 PM
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Gyro gain control without transmitter

Can I make a litle control for gyro gain ?
I use the gyro all the time in HH mode and I use 1 channel from reciver for gyro gain control. I need a litle generator for control this channel and use this free channel to control another function.
Also like servo tester but more litle for mount in hely.
Pic servo terster not work because not save pozition when cut power.
Analog solution with 555 is not too precise.
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Old Mar 01, 2008, 07:27 PM
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Quote:
Originally Posted by ciufuliciboy
Can I make a litle control for gyro gain ?
I use the gyro all the time in HH mode and I use 1 channel from reciver for gyro gain control. I need a litle generator for control this channel and use this free channel to control another function.
Also like servo tester but more litle for mount in hely.
Pic servo terster not work because not save pozition when cut power.
Analog solution with 555 is not too precise.
How would you want to set the gain? It would be easy to make something like this from a PIC (with EEPROM memory), but you would have to say how you would want to set it.

Mike
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Old Mar 01, 2008, 10:24 PM
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Originally Posted by mike50
How would you want to set the gain? It would be easy to make something like this from a PIC (with EEPROM memory), but you would have to say how you would want to set it.

Mike
Sounds like overkill.

http://www.uoguelph.ca/~antoon/gadgets/servo3.htm
http://www.tuug.fi/~isaarine/electronics/servo-test/

Toshi
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Old Mar 01, 2008, 11:03 PM
"Simplify, then add lightness"
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What do you mean "555 is not too precise"? A 555 will be as precise as anything you set with a pot. If you meant stability, the 555 will be very stable when built with temperature stable resistors and caps.
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Old Mar 01, 2008, 11:08 PM
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Overkill? The solutions you linked to are far more complex than a PIC solution. A PIC "servo tester" circuit can be done with fewer parts and more cheaply.

Mike
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Old Mar 02, 2008, 12:01 AM
"Simplify, then add lightness"
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Cost for any of the solutions would be so low as to be negligible. The analog solutions would take a few more resistors and caps, but even if he were an expert programmer and all set up to program PIC's I bet it would take longer to write the code and debug it than it would take to wire in the extra r's and c's. If he were an expert programmer and all set up to program PIC's, then he wouldn't have even needed to post the question.
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Old Mar 02, 2008, 04:07 AM
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Quote:
Originally Posted by mike50
How would you want to set the gain? It would be easy to make something like this from a PIC (with EEPROM memory), but you would have to say how you would want to set it.

Mike
Manualy, with up/down button or with semireglabil rezistor.

I am electronic tehnician but not programmer.
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Old Mar 02, 2008, 09:07 AM
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Quote:
Originally Posted by ciufuliciboy
Manualy, with up/down button or with semireglabil rezistor.

I am electronic tehnician but not programmer.
If you are looking for the lightest solution, you could make it so that it could be set from the transmitter. It could be made so that it could be plugged into the receiver, and to pass through whatever signal it got from the transmitter. It would remember the last signal it got, so that if it gets no signal it would use the last remembered value...and this could be remembered across turning the power off.

So after setting up the gain from the transmitter, then the circuit would maintain that value even when not plugged into the receiver.

This could be made easily with a PIC (such as 12F683) which has EEPROM to store the value across power off.

Mike
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Old Mar 02, 2008, 12:10 PM
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Quote:
Originally Posted by mike50
If you are looking for the lightest solution, you could make it so that it could be set from the transmitter. It could be made so that it could be plugged into the receiver, and to pass through whatever signal it got from the transmitter. It would remember the last signal it got, so that if it gets no signal it would use the last remembered value...and this could be remembered across turning the power off.

So after setting up the gain from the transmitter, then the circuit would maintain that value even when not plugged into the receiver.

This could be made easily with a PIC (such as 12F683) which has EEPROM to store the value across power off.

Mike
Very good solutioun but I am not programmer
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Old Mar 03, 2008, 10:15 AM
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I am starting work on a different project that will be using a PIC 12F683 and I am pretty sure that the hardware setup for that project would work for yours. Since I am designing and building this circuit anyway, I could build you one just for the cost of the components (about $5 US) and shipping. It would just require a different program...which is easy for me. I would do that for fun.

Have you actually tried using a servo tester to control the gain? Does that work?
It is possible that some gyros need the gain signal to come at the same frame rate as the signal being controlled. With an external device like a servo tester the signals will come at independent rates, which might confuse the gyro.

Mike
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Old Mar 04, 2008, 04:22 PM
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Originally Posted by mike50
Overkill? The solutions you linked to are far more complex than a PIC solution. A PIC "servo tester" circuit can be done with fewer parts and more cheaply.

Mike
As far as I know, in order to use a PIC, you need a PIC programmer.

So if you include the cost of the PIC programmer, then a solution using a PIC is probably more expensive.

Toshi
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Old Mar 04, 2008, 05:38 PM
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Originally Posted by TMorita
As far as I know, in order to use a PIC, you need a PIC programmer.

So if you include the cost of the PIC programmer, then a solution using a PIC is probably more expensive.

Toshi
The same need solder , flux . cable , connectors .......... etc.
Very constructive your help.........
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Old Mar 05, 2008, 05:36 AM
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Quote:
Originally Posted by ciufuliciboy
Can I make a litle control for gyro gain ?
I use the gyro all the time in HH mode and I use 1 channel from reciver for gyro gain control. I need a litle generator for control this channel and use this free channel to control another function.
Yes!

I did exactly this a few months ago. See this post for a picture of the finished controller. Cost about $5, weighs 5 grams.

I used this 555-based circuit. I am no electronics technician, but I can read a diagram and use a soldering iron. A PIC would take much longer, and will not be any more "precise". But if you really need up/down buttons, I guess a PIC is your best bet.

My controller is currently attached to a Logictech 2100t, which works beautifully because that gyro has a row of indicator LEDs. As I turn the pot, the LEDs update in real time to show the mode and percentage of gain. I am ~very~ glad the 2100t has this readout - it made it practical to use a tiny pot!

FWIW I also found this prefab driver,. But I was determined to do it myself. The result was both cheaper and lighter.

I still have a Jameco invoice in my parts bin. Lemme know if you want the component numbers.

Quote:
Originally Posted by mike50
It is possible that some gyros need the gain signal to come at the same frame rate as the signal being controlled. With an external device like a servo tester the signals will come at independent rates, which might confuse the gyro.
I doubt this would be a problem with any RC gyro you are likely to find. Anyway, I can confirm empirically that my ~50hz gain controller works with a Logictech 2100t that is sending a 270hz signal to the servo.

-Jeff
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Old Mar 05, 2008, 12:20 PM
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I will try to use 555 chip.
Thanks spinup for your help. My gyro is the same 2100T.
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Old Mar 08, 2008, 05:18 AM
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I tested 555 schematics and gain led from gyro ( 2100T ) it is stable in one point but with litle up/down fluctuation .
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