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General description of push buttons and switches. Push buttons are momentary switches where the button must be held down to create a connection between its leads. Switches are generally devices that stay connected or stay not connected depending on the physical state of the switch (the lever is moved to the other side, or the switched is depressed and an internal mechanincal system has caused a change in the state).

General description of a push button switch and button switch schematic symbol. The push button is a momentary switch that will only cause its leads to connect when held in a pushed condition.

Schematic of a push button connected to a microcontroller. One lead of the push button is connected to a general I/O pin of the microcontroller and the other lead is connected to either ground GND or power VCC. If it is connected to ground, the pin should be set high, if the lead is connected to VCC, the pin should be set low.

General explanation of push button and switch bounce. Removeing the push button or switch bounce is called debouncing the swith or push button. Debouncing can be addressed in two ways, software debouncing and hardware debouncing.

Connecting a push button switch to the microcontroller on a breadboard with a capacitor for hardware debouncing. The push button switch is connected to a general IO pin (in this case PORTB and Pin 1).

Programming for push button switch functionality on the Atmel AVR microcontroller on PORTB Pin 1 using the condition that uses the bit_is_clear(PIN?, ?) function. In this case, the push button has a capacitor to provide for hardware debouncing.

How to make a program for the Atmel AVR microcontroller using a push button to change the delay that an LED is blinking. The program uses the util/delay.h library and _delay_ms(delayAmount) function. Two delays are used: a 10 millisecond delay and a 100 millisecond delay.

How connect a push button to a microcontroller (make a circucit) and make a program for the Atmel AVR microcontroller using a push button to change the delay that an LED is blinking. The program uses the util/delay.h library and _delay_ms(delayAmount) function. Two delays are used: a 10 millisecond delay and a 100 millisecond delay.

Schematic on paper of one button with hardware debouncing and two LEDs (Light Emitting Diodes) connected to an AVR microcontroller. The push button switch is connected to pin 1 on PORT B and the LEDs are connected to pin 0 and pin 2 on the same port. These are green LEDs so a 330ohm resistor is used to limit the current through the LED.

Example of why debouncing for a push button is so important. The video shows schematic on paper of one button with hardware debouncing and two LEDs (Light Emitting Diodes) connected to an AVR microcontroller. The push button switch is connected to pin 1 on PORT B and the LEDs are connected to pin 0 and pin 2 on the same port. These are green LEDs so a 330ohm resistor is used to limit the current through the LED. The circuit is created on a breadboard and a program is written to toggle the two LEDs.

Breadboard circuit of one button with hardware debouncing and two LEDs (Light Emitting Diodes) connected to an AVR microcontroller. The push button switch is connected to pin 1 on PORT B and the LEDs are connected to pin 0 and pin 2 on the same port. These are green LEDs so a 330ohm resistor is used to limit the current through the LED.

Making a program for the Atmel AVR microcontroller to toggle two LEDs when a push button switch is pressed. When the push button is pressed and released, one LED is on, and when the push button is pressed and released again, the on LED is turned off and the other LED is turned on.

How to make a program for the push button switch for an Atmel AVR microcontroller so that the action is only activated when the push button is pressed then released. A condition using the function bit_is_clear is used to test for the push button press and then a variable is used to determine pressed state and released state. Within the condition, there is another condition to determine if the push button is in the released state before the push button is pressed. This means that the push button must have been released before the push button pressed action is invoked.

A test of the actual circuit with the Atmel AVR microcontroller programmed showing the push button without any debouncing and two LEDs toggled when the push button is pressed and released. Results show that without debouncing the LEDs sometimes toggle twice or three times with one button pressed and release.

A test of the actual circuit with the Atmel AVR microcontroller programmed showing the push button with debouncing using a capacitor across the two leads of the push button switch. Two LEDs (Light Emitting Diodes) are toggled when the push button is pressed and released. Results show that without debouncing the LEDs sometimes toggle twice or three times with one button pressed and release.

Showing the bouncing (mechanical bounce) effect of a push button switch using an oscilloscope showing the effect of the voltage level when the push button is pressed.

Showing the bouncing (mechanical bounce) effect with an oscilloscope for a push button switch with hardware debouncing introduced using a capacitor showing the effect of the voltage level when the push button is pressed.

The rationalle of using one method over the other and the tradeoffs. In software debouncing, the trade off is the microcontroller requires a few more cycles which can slow the execution of the program slightly and the variables needed for software debouncing requires a bit of memory. The trade-off with hardware debouncing is that the extra hardware (capacitor or capacitor/resistor pair) will introduce a cost to the circuit where if the circuit will be used in a product that will have thousands, or many thousands of units made, a hardware solution may be too expensive.

A program is developed and circuit is breadboarded to investigate debouncing through software. A few variables are created to measure the confidence level of the press and release. Two LEDs are added to the circuit to determine is the debouncing is operating successfully. If the LEDs toggled twice or more, then the debouncing would be unsuccessful. There is a threshold that only allows the button to create an action if the confidence level is above this threshold.

Two LEDs and one push button is connected to an AVR microcontroller on PORTB. The LEDs are connected to pin 0 and pin 1. The push button is connected to pin 2.

A program is developed to investigate the elimination of button bounce (software push button debouncing). The circuit consists of two LEDs and a push button. The LEDs will toggle when the push button is pressed and then released. Two main variables are used in understanding the actual button press and button release. These are confidence levels of pressed and released. A threshold controls the button action.

An attempt is made to explain how the software debouncing works. A string of 0s and 1s are visually represented to show what may be going on when a button is pressed and a solution to overcome the portion of the 1s and 0s where there is uncertainty. A counter is used to increase a variable to represent the confidence level of the button press or release.

A push button is tested to determine if software debouncing is successful. Microcontroller used is an Atmel AVR Atmega32. Two LEDs are used to check if the button exhibited a bounce.

7 LEDs are connected to PORTB pins 0 to 6. The 7th pin has a push button. On PORTD 7 LED are connected to pins 0 to 6 and on the 7th pin a push button is connected to the AVR microcontroller.

7 LEDs are connected to PORTB on pins 0 to 6 and a push button is connected to pin 7 on that port. On PORTD, 7 LEDS are connected to pins 0 to 6 and one push button is connected to pin 7. Resistors are connected in series with the LEDs to limit the current so the LEDs don't burn out.

An AVR microcontroller program that uses two push Buttons and 14 LEDs where each player has one push button and 7 LEDs. The object of the game is to press the push button faster than the opponent. The 7 LEDs will light up in sequence as the push button is pressed until the last LED lights up. The first player that lights the last LED on their side wins.

An example of a conditional statement if (condition){ do this code } else { do this code}. This particular conditional statement is meant to be used for a button press.

A Push Button and 7 LEDs are Initialized on PORTD and PORTB. The Push Button is located on the 8th pin (pin 7) on each port and the 7 LEDs are located on the remaining pins of each port.

Similar code is put into a single function to be called by two uses. In this example, two push buttons are needed to be read (evaluated) and a set code needs to be executed when each of these push buttons are pressed and released. Since these two push buttons will perform similar actions, the code is taken into a single function to be called by each of these push button conditions. Array is used in this code.

Similar code is put into a single function to be called by two uses. In this example, two push buttons are needed to be read (evaluated) and a set code needs to be executed when each of these push buttons are pressed and released. Since these two push buttons will perform similar actions, the code is taken into a single function to be called by each of these push button conditions. Array is used in this code.

A push button library is created from code written previously to test for button presses and releases and includes software debouncing (debounce). Atmel Studio 6 was used in this video. The library was put into a folder that is used for general includes so including this library would be a simple statement.

A function that contains a return is prefixed with a type name. If the function has parameters to be passed in, the parameters will be contained in parenthesis and suffix the function name. For example, a function that returns an integer and has a char parameter would look like this:

The Example in the video was created for the ButtonPress library.

Initializing two push button and two LEDs using binary notation. The push buttons will be connected to pins 0 and 1 and the LEDs are connected to pins 2 and 3.

Using the buttonPress library for the Atmel AVR microcontroller. The function is called ButtonPressed and it returns a char for testing if the push button is actually pressed. The parameters are the button number, port where the button is connected, pin of the port where the button is connected, and the confidence level threshold.

The transmitting microcontroller will output the communication from its TX transmitter pin to the RX pin of the receiving microcontroller. A wire will be connected from the TX of the transmitting microcontroller to the RX of the receiving microcontroller.

A button on the transmitting microcontroller will initiate the transmission through the TX pin. The LED on the transmitting microcontroller will serve as an indicator that the push button is working. An LED on the receiver microcontroller will serve as an indication of a successful communication.

The push button switch is connected to the first pin of the microcontroller (PORTB Pin 0) and the other end of the button is connected to ground since the pin will be in a high state.

This is the result of the one way communication of one microcontroller transmitting through its TX pin and another microcontroller receiving through the RX pin. A push button switch is connected to the transmitting microcontroller to initiate the transmit. Both microcontrollers have an LED to show the successful push button switch press and the show a successful transmission on the other microcontroller.

Use the W A S D E D while the right mouse button is pressed to move up (Q), down (E), side to side (A and D) and forward and backward (W and S).


With an actor selected in the level, click the right mouse button in blueprint graph to bring up a context menu and select add reference to actor. The name of the actor will be presented in that option.


With an actor selected in the level, click the right mouse button in blueprint graph to bring up a context menu and select add reference to actor. The name of the actor will be presented in that option.


Press the right mouse button on the graph of the blueprint and click on add events and click on events begin play.


Click and drag a wire from the white execution pin and release the mouse button and type delay and select the delay option. Set the delay in seconds or partial seconds since this is a float number.

Select the class blueprint object in the level and in the details tab, there is a blueprint category. Under the blueprints category, click on the edit button.

First, select a mesh that you would like to use as a pickup in the content browser. Right click on that mesh and select create a blueprint. Name the blueprint and select the folder that you would like this blueprint to be saved.

The mesh will need to have no collision, so it is possible to walk through it. To do this, select the mesh in the blueprint and go to the details panel and scroll down to Collision and in the collision presets, select overlap all.

Go to the graph and select the mesh in the My Blueprint panel and in the graph, press the right mouse button to bring up the context menu and select add OnComponentBeginOverlap event.

A node to destroy the pickup mesh will be needed so the mesh will disappear when the pawn touches the pickup. To do this, right click on the graph and type destroy and select destroy actor.

To show the particle effect, an emitter node is added by right clicking on the graph and typing emitter and select spawn emitter at location.

Under the emitter template, select the particle effect that you would like to use to show the destruction of the pickup actor. Use a get actor location node for the location of the spawn emitter.

Wire the BeginOverlap event to the spawn emitter and the spawn emitter to the destroy actor.

Open the character blueprint. There may already be a graph that contains quite a bit of logic for the character.

Setup a node to accept input from the mouse. Right click on the events graph and click on Inputs, then mouse events and then left mouse button. This will add a left mouse button press event.

Now, a spawn actor node must be added. Right click on the graph and type spawn actor. Click on spawn actor from class.

Connect the button press event (white execution wire) to the SpawnActor node.

Add a get actor location node so the spawning can originate from the character and add a get control rotation to rotate the projectile appropriately. These are both found on the context menu by right clicking on the graph.

Drag from the control rotation node and type forward and click on get forward vector. This will direct the projectile forward from the character. Multiply this forward vector by 100 by using the vector multiplication by float. Add this new forward vector to the actor location node using the vector plus vector node.

Add a make transform node to the graph from the context menu. Connect the vector vector addition node to the location pin on the transform node and connect the control rotation node to the rotation pin on the transform node.




Thanks for the push button code and ADC examples Patrick. Your website motivated me to transition from Arduino and Intel Edison (in mraa) to the real deal.

Best wishes,
Jordan

Thanks for the push button code and ADC examples Patrick. Your website motivated me to transition from Arduino and Intel Edison (in mraa) to the real deal.

Best wishes,
Jordan