Single HD Gyro Image Stabilizer

Intro: Single HD Gyro Image Stabilizer

STEP 1: History

Before making my 2 Gyro stabilizerhttps://www.instructables.com/id/Universal-2-Gyro-Image-stabilizer/ from 2 hard disks, I had been thinking about the concept for about a year.

In an experiment, I connected a loose HD to a computer power supply, and felt the resistance to its change of  position. I figured a HD in the horizontal and one in the vertical plane (X- and Y- axis) would dampen almost all unwanted shaking.

The 2 Gyro stabilizer model is very successful, but practical use of the device is limited, due to bulk and weight.

A single Gyro has its theoretical limits. A strong Gyro in the front / back plane (Z - axis) could dampen shaking, but would not correct rotation. But if rotation around the optical axis is only a minor component of motion blur... , the advantage is less weight and power requirement.

STEP 2: Design

The camera is mounted on a hinge with fastening screw. The other part of the hinge mounts a HD.
The HD can be tilted in the vertical ( Y-) plane from way under the camera to a hugging position for storage.

(my understanding of...) the theory would indicate the best position of the axis of rotation is parallel to its optical axis.

But in this design, any position of the HD Gyro can be tested. It also makes storage and transport much easier than the 2 Gyro model.

STEP 3: Materials

For the gyro  I had a 80 Gb 7200 RPM single platter HD, still in use for external backups.

2 USB car phone chargers convert the 12 V lead cell input power into 5V, 800 mA max. (HDs need both 5 and 12 V, the newer SATA HDs need 3.3 V as well).

A simple hinge has the pin taken out. Instead a piece of M8 thread holds the hinge together. A small tube is put over it as a spacer and a knob at the end allows fixing the hinge in any desired position.

A small plate of aluminum is attached to the camera side of the hinge, to provide space for the HD in park position (not too thin, think about stability!).

A piece of poplar wood, from one of them knicknack wooden boxes, covers and protects the delicate backside of the HD.

STEP 4: Electronics

A HD needs 2 or 3 voltages (3-4 leads) to function( 12V, 5 V, the newer SATA disks also 3.3 V, and of course ground/ 0V).

Most older HDs, the ones with a Molex connection, only need 12V and 5V. Although the spinning motor needs only 12 V, the HD won't work unless it is supplied with both voltages.

Power requirements for any model HD can usually be found on the sticker at the top of the HD, or on the manufacturers' site.

Cheap (2 E) USB car phone chargers transform 12 V DC into 5 V DC. The output of a single charger is ca. 400 mA.

2 of these chargers were wired in parallel, to meet the start-up power spike requirements (the arm of the HD only makes a few moves during start-up; afterward it doesn't do nothing).

My power supply is a small 12 V lead acid battery. A ca. 1m (3 feet) flexible wire ending in a car 12 V socket supplies it to the device. The battery can be worn in a small shoulder bag or on a waist belt. Plugging it in or out is the 'on/ off' switch.
(Other types of 12V batteries are possible as well; with a setup looking quite different).

The car phone chargers come in a ' car plug' format. After the circuit boards were soldered in parallel, one plug was left intact, while part of the housing of the other one was put behind it. Some hot glue, duck-tape and a piece of bike inner tube made it more sturdy : almost like a laptop power supply!!!

STEP 5: Testing

The old (finished Sept 24th) 2 Gyro system provides a great stabilization, but is quite bulky. Not that easy to take into the field...

This 1 Gyro design is far more easy to handle in the field, cheaper, folds up, stores easily, uses less power and is easier to build.

Testing was done during  mid twilight. The camera was a Canon SX 110 IS, at 10X maximum zoom setting (330 mm focal length 35 mm equivalent).

Exposure was set at 1/ 15 sec: Impossible to avoid motion blur if held by hand.

DISCUSSION OF RESULTS:

With some training, this stabilizer performs almost as well as the far more bulkier 2 HD stabilizer.

Training is important: Holding the camera in a steady, horizontal (unrotated) position is easy. But when pressing the shutter button, a beginner like me tends to move his whole arm instead of just his finger.  Which results in rotation of the camera...

Rotation around the optical axis is the only unstabilized motion in this design.

Fortunately, with some practice, pressing the shutter button while holding the camera steady, is easily learnt.

I would have preferred the multi platter HD. The gyro power of this particular HD feels a bit light.

STEP 6: Possible Further Improvements

1) Making a strap: too many devices! Camera, battery, stabilizer and bag. After use, stuff needs to be taken apart and stored. Normally, the 'feel' of the camera weight  make sure things are properly taken care of. The presence of yet another device is hard to notice.  This confusion makes it easy to drop things (I almost dropped it when taking the camera off)!

2) The HD could be be protected by rubber or insulation foam strips. A serious, multi- platter HD can carry many images, videos or data, as an 'image tank'.  Wiring kits to convert the HD into an external storage device are cheap. But, if taking the stabilizer into the field, one should really have another backup...  (Of course, this depends somewhat on what one considers ' the field': is it your back yard or a war zone?).

3) Making sure all connections are tight and water proof.

On stronger motors: CD/DVD and HDD spindle motors are being hacked by the RC model plane community. With thicker wiring and replacing the ceramic magnet ring with Neodymium magnets they seem to reach up to a whopping 400 W output. Machining of a new rotor (bell) and controller ('esc') is required +a high output battery pack (LiPo), which would make a gyro project no longer low budget nor fast to assemble. It could provide another dramatic reduction in size and weight though. Link:www.flyelectric.ukgateway.net/machin.htm

Comments

[mchazlitt]

How do you keep the HD from spinning down?

I have some HDs coming, I want to take the spacers out and replace with more platters, to increase the inertia.

[RachaelSP]

Have you considered trying a 2.5" hard drive from a laptop? I wonder if it would produce enough force to provide stability for a camera. They run on 5 volts so the 12 volt supply could be eliminated.

I'm curious what voltage is actually used for the platter motor, if I can find another junker drive at work I'll check. I just trashed 5 old scsi drives last week... Perhaps you could still eliminate one of the voltages with a 3.5" drive. You should be able to get rid of the PCB as well, and run the power straight to the motor. The magnets and head assy can be removed. The magnets and their mounting plates add quite a bit of weight.

Good idea, its a good use for a bad hard drive.

[yaly]

weight is good as long as it's comfortable to hold

[patrickcleary]

You can't run the power straight to the motor, it's a DC brushless spindle motor. You need the driver circuit on the controller board to run it, unless you make your own driver circuit. Also, a laptop drive would theoretically work, except that you'd have smaller, lighter discs. Today I finished putting my own hard drive gyro together, but I eliminated the spacers and the read/write assembly and packed it with as many platters as could fit (9 in my case) and super glued them all together. Now for the driver circuit!

[yaly]

I guess a microdrive such as the 1.8" in iPod Classic would be nice, they're 4200 RPM drives, the only need 3.3 volts, so a much smaller battery is needed. Although they use a ZIF connector which is hard to find somehow, there are two soldering pads next to the ZIF socket on many of them for auxiliary power. Please tell me if anyone had any success with that.

[fizzzbang]

Wonder if laptop drives would work but I guess you need the spinning mass right?

[noahspurrier]

The kinetic energy in a gyro is proportional to the square of the angular velocity, but only linear in proportion to the mass, so the speed of rotation is the significant factor.

[Pikaubanitro]

Brushless motor for RC helicopter!
http://www.hobbyking.com/hobbyking/store/__17922__NX_4005_650kv_Brushless_Quadcopter_Motor.html

[mpritchard4]

SATA drives ought to still run on 5V and 12V, otherwise the Molex-to-SATA converter leads wouldn't work. Nice tutorial!

I've been playing with an old Seagate five-platter SCSI drive today, poking and prodding the TPIC1533 motor drive IC. Unfortunately whilst the motor runs on 12 volts, and one side of each driver (pulling the motor wire down to ground) uses 12 volt pulses, the other side of the driver (pulling the motor wire up to 12 volts) uses pulses of 24 volts so that's yet another supply rail to deal with! Obviously other drives may be easier (or harder) to control, but for this old Seagate I need a 6 phase, 480Hz, 12/24 volt power supply so it's a job best left to the drive itself!

Swings and roundabouts with faster drives, too. 10K drives have slightly smaller platters, 15K drives smaller still (think 2.5" platters in a 3.5" drive and you get the idea) so the increased gyro speed (and whine) is countered by the decreased spinning mass.

[Morgantao]

I tried to do the same kind of gyro a while ago, with 3 different HDs (two Wenstern Digitals and one Seagate), and all gave me the same problem...
When I connect them to a PSU the spin for a few seconds and then stop. the only way to start them spinning again is to disconnect them from the PSU and reconnect.
How do I keep them spinning for more than a few seconds at a time?

[bknight2]

I used two rumble motors from a game controller,
took off the weights,
mounted two at vert and horiz,
two 9volt batteries in a small plastic box with foam to hold in place,
and velcro'd it onto my DIY steadycam rig and it kept the rig more stable than without. I thought it would be too small to have any effect, but, it worked a little bit.
I got the idea from this very article or "ible".
Thanks.
You can use just a couple of small electric motors, cheapo units that are bigger than two fingers, it will work.

[lavmal]

Great what you "invented"/discovered yourself. Would be great, if you can transfer images right to the HD:D

[southa]

The Kenyon stabilisers work differently to this - see the original patent: http://www.google.com/patents?id=VI9NAAAAEBAJ A gyroscope on its own just turns a force in one direction into movement in another. I'm guessing that the gimbals shown in the patent are important.

[arikyeo]

 use a car battery?! that removes the portability! maybe use a few batteries with a step-up transformer?

[BobS]

You know, when taking it into the field for a few times, these things come into consideration. Right now, I'm quite happy to put this small scooter battery in my inseparable shoulder bag. When still doing experiments, the last thing one wants is to have to go back home because the power source ran out of juice! A rechargable NiCd battery in decent shape could be substituted.

For video, or when going on a long trip, I think this is still one of the better solutions.

For urban use your suggestion seems excellent. I think a cell phone battery (Li-ion) would be the best candidate.

[patrickcleary]

I just finished wiring up 12 D-size batteries, but they don't seem to provide enough amperage to start the spindle. When I tested mine (granted, much more massive spindle due to more platters), the motor drew a peak of a bit over an amp! What to do about the power supply??

[dave950]

You bet me too it, I was going to do this. Where else can you find something that spins at high RPM and is balanced?

[bazeemuth]

Do you notice much difference in the behavior of your one- and two-gyro models?  According to what I remember from physics, two gyros should act the same as one gyro, with the two gyros adding up to the effect of a single gyro oriented at 45 degrees (halfway) between the two.

[BobS]

Could very well be! Now spring is coming, I hope to take the camera +rig out and find out...

[amclaussen]

Excellent Instructable  Bob!
I cannot add any suggestion at this moment to improve it. Reading about your comment on your difficulty of holding your camerasteady when shutting, I remembered an Idea that I use to train people onhow to properly hold as camera and softly press the shutter button, itis by using a laser pointer temporarily attached to the camera to showhow much movement is done when pushing the shutter button down. Keep practicing until the laser dot projected onto a wall lookssteady.  The tool-like lasers like the Black and Decker can projecta pair of lines at 90 degrees, which helps in developing a sense ofhorizontality to properly level the camera too.

Finally, practice placing your finger laying on the camera body top, andusing ONLY the fingertip to SLOWLY squeeze the shutter,avoiding pushing the whole camera when operating the shutter.  Theold rule of thumb in 35 mm photography was to select a shutter speedreciprocal of the lens focal distance; that is, if using a 135 mm shorttelephoto, one should use at least 1/125 second exposure with hand heldexposures.  But with modern image stabilized lens or sensor, anaverage two stops can be saved (that would be 1/30 sec.) Now, using yourHard disk stabilizer can add at least one more stop. This is anexcellent idea and I truly commend you for your approach. Keep-up thegoog work!
amclaussen, Mexico City.