Gyro in Robonova-1 ?

[rossoe]

Anyone thinking of getting this little Dual Axis ?

http://www.sparkfun.com/commerce/produc ... cts_id=698

[KurtE]

Yesterday my shipment of add on componants arrived from SparkFun. This included one of the IDG-300 break out boards. It also included a BlueSMiRF and a MaxSonar-EZ1. Hopefully I will have time over the next couple of days to try to integrate these into my RN-1.

This will be the first time that I ever tried anything with a Gyro, so I would appreciate any hints anyone might have. Some issues that I need to resolve include.

1) This chip requires a 3.3 volt supply. What is the best way to archive this? I believe I read where someone here replaced their power regulator with a 3 volt variety. However some other things like the EZ1 requires 5 volts. Would a couple of resistors do the trick?

2) There are 5 pins going into this board. There appears to be three output signals and no inputs. So what do I do about the Gyro #1 and Gyro #2 inputs? The pins are as follows:
3.3V and GND -
Yout - Gyro #1 output (AD 0)
Vref - I believe this is 1.23V precision reference output
Xout - Gyro #2 output (AD 1)

3) There is no user controllable trimming! There are several pins to the actual chip that the description as reserved for factory trimming.

Do you think this chip/breakout board has a reasonable chance of working OK or would I be better off going to some more known Gyro such as the PG-03?

Again I would appreciate any suggestions you might have!

[yag-freak]

I have not done this by myself, so anyone correct me if I am wrong.

1) This chip requires a 3.3 volt supply. What is the best way to archive this? I believe I read where someone here replaced their power regulator with a 3 volt variety. However some other things like the EZ1 requires 5 volts. Would a couple of resistors do the trick?

I have the same problem in mind. A few Roboteers modified the Controllerboard to 3,3V. But I also have the issue that I have planned some sensors requiring 5V (with no 3,3V version available).

I think I will stay at 5 V and regulate down to to 3,3 V with some Voltageregulator for the few 3,3V devices. As I don't need much current it'll be OK.
You can get those regulators at the electronic-shop for a few cents. They smallest do 1A, which is more than enough. So they won't even get hot.

2) There are 5 pins going into this board. There appears to be three output signals and no inputs.

There is a difference between the gyro like the PK-03 and the IDG-300.

The PK-gyro gets a servo-signal from an receiver/controller as input. This is a pulsewidth modulated signal.
Then the gyro changes the pulse width when turned in space and outputs the modified PWM-signal.
So normaly you hook up the gyro to the receiver and the servo to the gyro.
example:
The receiver sends zero position to the servo (1500 pulse) and the gyro is not moved => servo goes to zero position.
If you move the gyro the pulse becomes modified (perhaps 1600 pulse) and the servo responds. If you have choosen the right direction, the servo brings back the system until gyro is in normal position and the gyro will again output the 1500 original signal.

So the controller has to output PWM to the gyro, gets back the modified signal and has to look for the difference between both.
Quite complicated, but you can use every cheap RC-gyro.


The IDG-300 just simply puts out an voltage analog to the tilt of the sensor. Look for the data-sheet.

So there is no input, just the output of the voltage.
You have to connect the IDG to an AD-Port of the controller and read out the voltage. That's your signal.

[KurtE]

Thanks for the input!

From your input, it looks like this chip will be a lot easier to work with then some others as you don't have to deal with all of the GYRO specific basic commands. Sounds like it should be fun!

Unfortunately I have been very busy the last few days on non-robot related issues and have not had a chance to do much yet.

I tried stopping at a local Radio Shack and they did not have any 3.3 volt regulators in stock. I will try a different store or order one online later. In the mean time I was wondering if it would make sense to hook this device up using a couple of resisters. My electrical design skills are rather rusty, but do you think something like this would work?

+5V---R1--X--R2--GND

Where X is the tap to get the voltage. If I use the formula (V1 * R1)/(R1+R2) = V2, then in this circuit if for example I choose R1=100 and R2=180, I believe my voltage at X should be 3.214 volts, which is in the target 3 to 3.3 volts. I know that there are many other chooses for R1 and R2 that would work. The question is how to choose these such that I can provide enough current to this chip that if I understand the specification correctly needs 9.5 mA, without wasting to much battery power. If I remember correctly V=IR, so if there was no tap here:

The current would be: 5/280 or about 18 mA.

Does this make sense? Hopefully later today I will try bread boarding this to see if this works or not.

Thanks again.

[H3dude]

I've never installed a gyro before but I have seen it done here so I'm confident I have a Futaba G190 micro-piezo gyro and it is extremely small 22x22mm. I've got nothing but free time until monday so I'm going to try to hook it up now and see if I can get it to work. If anyone has any ideas or suggestions on how to wire it to the leg servos please let me know. Right now I'm thinking of a simple Y harness (splitter) on both ends.

here's info on the gyro- a bit pricier than the GWS but a LOT smaller and apparent;y much more sensitive.
http://www2.towerhobbies.com/cgi-bin/wti0001p.pgm?&P=PR&I=FUTM0830

Length: 0.87" (22.2mm)
Width: 0.90" (22.8mm)
Height: 0.35" (8.9mm)
Weight: 0.24oz (6.7g) including connector
Operating Voltage: 4.8 to 6.0VDC
Current Drain: 15mA at 4.8V
Operating Temperature Range: -5 to +45ºC
Functions: Sensitivity trimmer and LED monitor

wish me luck!

[H3dude]

Success Seems like it's working fine, and it's super-sensitive to boot. I've only managed to connect it to the one knee servo.

So here's a question for all: how I can use it on the knee servos of both legs without buying another gyro? I realize I can just split the output of the gyro and connect that to both knees, but that's going to mess up all my scripted leg movements obviously. Is there a trick or something that I'm missing?

[ucrobots]

Have a look on: http://robosavvy.com/Home/modules.php?n ... c&start=15

I think you should try GYROSET, GYROSENSE and GYRODIR.

[ANDYKONG]

I got reply from Hitec that my gyro can't be used in my robot. The problem is that it's a head-lock gyro. Does anyone know how to turn off the head-lock function? Thanks.

[dshinsel]

:) Thanks for the input!

From your input, it looks like this chip will be a lot easier to work with then some others as you don't have to deal with all of the GYRO specific basic commands. Sounds like it should be fun!

Unfortunately I have been very busy the last few days on non-robot related issues and have not had a chance to do much yet.

I tried stopping at a local Radio Shack and they did not have any 3.3 volt regulators in stock. I will try a different store or order one online later. In the mean time I was wondering if it would make sense to hook this device up using a couple of resisters. My electrical design skills are rather rusty, but do you think something like this would work?

+5V---R1--X--R2--GND

Where X is the tap to get the voltage. If I use the formula (V1 * R1)/(R1+R2) = V2, then in this circuit if for example I choose R1=100 and R2=180, I believe my voltage at X should be 3.214 volts, which is in the target 3 to 3.3 volts. I know that there are many other chooses for R1 and R2 that would work. The question is how to choose these such that I can provide enough current to this chip that if I understand the specification correctly needs 9.5 mA, without wasting to much battery power. If I remember correctly V=IR, so if there was no tap here:

The current would be: 5/280 or about 18 mA.

Does this make sense? Hopefully later today I will try bread boarding this to see if this works or not.

Thanks again.

I don't think this will work. The GYRO commands only work with PWM output gyros. I would guess that if you use AD() inputs, the reaction time would be WAY too slow for the Gyro to be effective.

[dshinsel]

Well, I finally got back to playing with my Gyros. As PEV mentioned a while back, I want to be able to turn the Gyro on and off.

When I try, it looks like the Gyro's can start OFF, but once turned ON, can not be turned OFF again! I think this may be a limitation of RoboBasic?

Can anyone can figure out how to make this work?

Here's what I'm doing:

gyro_off:
GYROSET G6A, 0, 0, 0, 0, 0, 0 ' set Gyro to use (0=no Gyro)
GYROSET G6D, 0, 0, 0, 0, 0, 0 ' set Gyro to use (0=no Gyro)
GYROSENSE G6A, 0,0,0, 0, 0, 0
GYROSENSE G6D, 0,0,0, 0, 0, 0
RETURN

gyro_on:
GYROSET G6A, 0, 2, 2, 0, 0, 0
GYROSET G6D, 0, 2, 2, 0, 0, 0
GYRODIR G6A, 1, 0, 0, 1, 0, 0
GYRODIR G6D, 1, 0, 0, 1, 0, 0
GYROSENSE G6A, 0,150,150, 0, 0, 0
GYROSENSE G6D, 0,150,150, 0, 0, 0
RETURN

[Pev]

Well, I finally got back to playing with my Gyros. As PEV mentioned a while back, I want to be able to turn the Gyro on and off.

When I try, it looks like the Gyro's can start OFF, but once turned ON, can not be turned OFF again! I think this may be a limitation of RoboBasic?

Can anyone can figure out how to make this work?

Here's what I'm doing:

gyro_off:
GYROSET G6A, 0, 0, 0, 0, 0, 0 ' set Gyro to use (0=no Gyro)
GYROSET G6D, 0, 0, 0, 0, 0, 0 ' set Gyro to use (0=no Gyro)
GYROSENSE G6A, 0,0,0, 0, 0, 0
GYROSENSE G6D, 0,0,0, 0, 0, 0
RETURN

gyro_on:
GYROSET G6A, 0, 2, 2, 0, 0, 0
GYROSET G6D, 0, 2, 2, 0, 0, 0
GYRODIR G6A, 1, 0, 0, 1, 0, 0
GYRODIR G6D, 1, 0, 0, 1, 0, 0
GYROSENSE G6A, 0,150,150, 0, 0, 0
GYROSENSE G6D, 0,150,150, 0, 0, 0
RETURN

Hi,

I am basically doing the same as you:

Gyro_On:

GYROSET G6A,0,1,1,0,0,0
GYROSET G6D,0,1,1,0,0,0

RETURN

Gyro_Off:

GYROSET G6A,0,0,0,0,0,0
GYROSET G6D,0,0,0,0,0,0

RETURN

And you are right it doesn't seem to completley turn off the gyro. I find it reduces it's sensitivity but not right the way. I have used this code to allow me to do the sitting down motion without the jumping about. I posted a video of the sitting issue with the gyro turned on previously, and here's the link to it:

http://robosavvy.com/Builders/Pev/rn1sitting.wmv

As I mentioned using the code above I can turn off the gyro enough to allow this sitting motion without the wild jumping about.

Hope this Helps

Pev

[H3dude]

Hey guys I need a little help with my gyro setup. Some clarification really, specifically on why are you guys are using the AD ports to connect the gyros to. I think, if I understand this correctly, that the AD ports are controlling the 4 groups- rt leg, lft leg, rt arm, lft arm. Is this correct?

So by running a separate gyro to each leg group you guys are achieving your results? Am I totally off???

Thanks

-v

[Pev]

Hey guys I need a little help with my gyro setup. Some clarification really, specifically on why are you guys are using the AD ports to connect the gyros to. I think, if I understand this correctly, that the AD ports are controlling the 4 groups- rt leg, lft leg, rt arm, lft arm. Is this correct?

So by running a separate gyro to each leg group you guys are achieving your results? Am I totally off???

Thanks

-v

Hi

I hope this helps but basically I run 1 gyro controlling both leg groups. The gyro is set up on gyro port 1 which is AD ports 0 and 4. The setup code is as follows:

'Gyro Setup
GYROSET G6A,0,1,1,0,0,0
GYROSET G6D,0,1,1,0,0,0

GYRODIR G6A,0,1,1,0,0,0
GYRODIR G6D,0,1,1,0,0,0

GYROSENSE G6A,0,200,200,00,0,0
GYROSENSE G6D,0,200,200,00,0,0

The GYROSET command tells the system what group is being controlled and the 1's in the comma separated string say which servos to effect by which gyro. As I only have 1 gyro on port 1 the value is always 1 to turn the gyro on for a given servo. So you can see from my setup I am controlling the upper ankle and knee servos for both the A group and D group (the two legs)

The gyro direction sets which way a servo will move in reaction to the gyro sensing movement.

Finally the GYROSENSE command sets the amount of movement per servo. Any value from 0 to 255 can be used - mine are set to 200. Again this relates to the servo in the group.

I hope that is a bit clearer but feel free to pm me if all I've done is confuse.

Pev

[H3dude]

Pev, now I understand Thanks so much for clarifying that for me.
So an additional servo for the 2nd leg group isn't necessary, correct?

[Pev]

Pev, now I understand Thanks so much for clarifying that for me.
So an additional servo for the 2nd leg group isn't necessary, correct?

Your right you don't need a second gyro (I am guessing you meant gyro rather than servo) infact you can move all the groups with one gyro including the arms - might be useful for counterbalance but I haven't had a chance to play that one out yet.

Pev