Persistence of vision fidget spinner- share project – pcbway anoxia neonatal causas

One of the most important characteristics is that the displayed graphics doesn’t depend on rotation velocity thanks to its innovative solution for keeping the track of rotation angle. Meaning that the displayed graphic is perceived the same at both, higher and lower rotational speeds (for instance, when the fidget spinner is slowing down when held in the hand).

The device is turned on by using a capacitive touch button which is embedded under the solder mask on the printed circuit board. The output from the capacitive IC PCF8883 is fed to the OR logic gate BU4S71G2. anxiety attack meaning in tamil The other input to the OR gates is a signal from the MCU. severe anoxic brain injury prognosis The output from OR gates is connected to the Enable pin of a step-down converter TPS62745.


By using this setup I am able to power on/off the device by using only one touch button.

Step down converter TPS62745 converts 6V nominal from the batteries to a stable 3.3V. I have choose this converter because it has high efficiency with light loads, low quiescent current, operates with a tiny 4.7uH coil, it has integrated input voltage switch which I use to measure battery’s capacity with minimal current consumption and the output voltage is user-selectable by four inputs rather than feedback resistors (reduces BOM). The device goes to sleep automatically after 5min of inactivity. The current consumption in sleep is less than 7uA.

The rotational angle is tracked "by hardware“ rather by software meaning that the CPU has a lot more time at its disposal to do other tasks. anxiety test pdf For that I have used Angular Timer peripheral which is built into the used microcontroller PIC 16F1619.

Input to the Angular Timer is a signal from Hall sensor DRV5033. The Hall sensor will generate a pulse every time a magnet passes by it. anoxia perinatal definicion The Hall sensor is located at the spinning part of the device while the magnet is located on a static part for which the user holds the device. Since I used only one magnet that means that the Hall sensor will produce a pulse that is repeating every 360°.

At the same time Angular Timer will generate 180 pulses per revolution in which every pulse represents 2° of rotation. I choose 180 pulses, and not 360° for instance, because I found 2° to be the perfect distance between the two columns of a printed character.

The device can be controlled via computer application programmed in LabVIEW graphics programming environment or by using a freely available smartphone BLE applications which has the ability to directly write to the selected BLE Characteristics of a connected device.

In the top-left corner we have controls for starting up the National Instruments BLE server application. social anxiety assessment pdf That is a command line application from NI which creates a bridge between BLE module on a computer and LabVIEW. It uses HTTP protocol to communicate. The reason for using this application is that LabVIEW only has native support for Bluetooth Classic and not for BLE.

Upon successful connecting, the MAC address of a connected device is displayed on the right and that part is not grayed out anymore. There we can set the moving graphics and its color or just send some pattern to turn the LEDs on or off when the device is not spinning, I have used that for testing purposes.

Because of that I developed a separate application in LabVIEW that takes the font generated in "The Dot Factory“ as input and transforms it to suit the needs of this project. Since the red and green LED PCB layouts are different I needed to use two fonts. The output for the green font is shown in the picture below.

To summarize, I would like to point out that by using Angul Timer peripheral I successfully achieved a POV device which doesn’t depend on rotational velocity, so the quality of displayed graphics is kept the same at both higher and lower speeds.