LED & Speed ​​Meter Power Ball / Wrist Ball

Power Ball - simulator
A work colleague bought a simulator for the hand. The whole department trained their hands. What came of it ...
The principle of operation of this simulator is based onprinciples of gyroscope. Everyone remembers Yulia (top), which is also built on the principle of a gyroscope. In a nutshell, the simplest gyroscope is a device in the form of a body rotating on a vertically standing axis, which serves to maintain the balance of some objects.

Powerball - a unique sports simulator. It replaces the expander, dumbbells and boring workouts. Moreover, I fully confirm that it is useful and not boring to train. Firstly, the competitive moment (both with friends and with oneself) pushes you to practice this simulator. Secondly, a lot of time training does not take.
Here are some Internet excerpts:

Gyro - Big Soviet Encyclopedia

The colleague did not save the box from the simulator (he said that she is the same as the photos from the site)
A complete set - the exercise machine, a rope for start and a lace for deduction of the exercise machine.
I will describe a little simulator.
In a plastic ball, two tops are cut off: instead of one, a plug with a microcomputer screen is inserted, and in the other, a gyroscope rotor is visible, which can be untwisted. On the side of the ball across the entire surface is a strip of rubberized material.
View from the side of the microcomputer (top)

Side part

Bottom part

Here is the rotor. There are holes (3-4 pieces) and a groove for laying the rope in the circumference (needed to start the rotor).
The rotor starts simply. Rope with one end inserted into the hole, rotate the rotor and put the rope in the groove. After the rope is fully laid, take the simulator in your hand (the upper part should be in the palm of your hand), and pull out the rope with your second hand. The rotor begins to spin. With a hand, we begin to smoothly make rotational movements, approximately one revolution per second. Then gradually increase the speed with a brush, seeking the promotion of the rotor. The stronger the rotor spin, the harder it is to hold the simulator.
Talk a little about the microcomputer
On it is a digital display that shows 5 numbers and 5 icons. Each icon shows which parameter is displayed.
In total, the computer has 2 buttons. The first button is the switching of the operating modes, the second is the switching on / off the device. If you press the second button for a long time, the current value on the microcomputer screen is reset.
View near the microcomputer screen

It shows 5 icons
The first icon (a dot, and around it in a circle are three arrows)
The numbers show the number of revolutions multiplied by 100 since the reset. The photo shows that the rotor made almost 16 thousand revolutions after the last reset.

The second icon (three arrows in a circle)
The numbers show the current speed of the simulator per minute

Third icon (curved arrow from bottom to top)
Shows the maximum number of rotor revolutions after reset

If you switch to this mode when the rotor is spinning,then instead of the third icon, the fourth icon will appear (curved arrow in a circle). The numbers in this mode show the maximum speed during the current promotion.
The fifth icon (curved hand). Shows how much time will be taken testimony. During the rotation of the rotor, this value is reduced by one in one second. This parameter has three values ​​of 30/60/90 seconds.

A dynamo is built into the rotor, which is connected to the LEDs. During rotation, the diodes flash red and green. It looks beautiful in the dark.
On the side surface there is a groove for fastening the lace

Here is the video where I spin the powerball.
The video could not be inserted here. Here is a link to youtube
In this video I rotated the rotor to 8778 rev / min. Not a good result.

Such devices can be bought offline. For example, we in SportMaster-e training apparatus sold at a price of 390 rubles. But he doesn’t have a computer and it’s almost doubled. In addition, the simulator is completely made of plastic (inconvenient to hold).
A similar simulator can be purchased at Tinydeal for $ 7.38
Add a link from the comments:
Simulator on buyincoins for $ 6.56
Briefly pros and cons:
1) perfectly trains hands
2) rubberized surface (partially)
3) microcomputer
4) lace so that the simulator does not accidentally fall out of hand
1) price
2) microcomputer weak point - reed switch. A friend has already changed, since the native worked intermittently.