Questions tagged [keyboard]

A Keyboard is an input device typically made of a large array of switches. The interface could be the raw matrix, or an industry standard protocol like PS/2 or USB.

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Spilling water to keyboard fixes keyboard weird [closed]

I have a laptop of about 5-6 years old. (A) key hasn't working properly for a while. But I spilled water on down arrow key and weirdly (A) key started working. How is this possible?
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replace individual 1n4148 with diode array

I have a side job with OhKeyCaps building mechanical keyboards. We use a amoeba single switch pcb which at the bare minimum (IE no rgb) requires a switch and a single 1n4148 diode. Fairly common stuff ...
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37 views

Fixing the wiring on a keyboard sustain pedal

I have a cheap keyboard sustain pedal of the basic on/off variety. When the footswitch is pressed down sustain is on, and off when it's released. There is also a polarity switch so that it can be used ...
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Keyboard PCB Design Review Request

I was hoping someone would be able to have a look at a schematic for a split keyboard I've been working on. I know there are quite a few designs online but most of them are using a processor on a ...
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Help needed finding laptop FFC keyboard connector

I have a Thinkpad T440 keyboard that I'd like to convert to a USB keyboard. I've been looking for an FFC connector for it and it's been difficult finding it. It has 32 pins and 0.5mm pin pitch. The ...
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54 views

Mechanical Keyboard PCB: Single Row Failure

I’ve got a weird issue on my hands and could use some advice. I built a mechanical keyboard and it worked for about a week, before the number row stopped working (no liquid damage or vibration/...
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59 views

Without the use of any software, what would be the cheapest way to connect my broken laptop's keyboard to my desktop?

I am trying to use an old keyboard from a laptop as a new set of keybindable keys for my desktop. I will worry about software side later what I need here is this: How can I use the keyboard from my ...
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2answers
29 views

Which programmer/connector can I use for a 6 pin header on mechanical keyboard design?

Forgive me, I am not an engineer but I wanted to figure out which connector I should use to program my custom mechanical keyboard design. The PCB has an Atmega32u4 controller which is connected to a 6 ...
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5answers
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Part information from schematic symbol

I don't understand what this part is from my keyboard PCB design. Someone else worked on the design and I can't figure out what it is.Please help! Here's another image including other parts of the ...
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1answer
34 views

LED matrix on keyboard

I want to build a keyboard from scratch which will be illuminated as well (one LED per key/switch). Due to the fact that I don't need some fancy stuff, just turn the LEDs on/off, can I connect entire ...
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37 views

Can keypad common be connected to microcontroller?

I want to use a keypad with a microcontroller. An example schematic is shown below. The pins 1, 2 and 3 are inputs with internal pull up resistors enabled and the pin 4 is output set to LOW. The real ...
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50 views

Keyboard libraries or simple code?

I am in research for building a custom keyboard using an Arduino or Teensy microcontroller. Concerning the programming of the M/C I have come across firmware libraries such as tmk or qmk. Yet I ...
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61 views

Keyboard switch removal problems

I recently put together a keyboard and had an issue with a couple switches so I decided to re-solder. I resoldered 2 and that fixed the issues but for this last one I started smelling something ...
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174 views

Schematic suggestions for a beginner

(From a complete beginner) I've had this idea to build my own keyboard from scratch for a while, and I finally got the time (and motivation) this winter break to go ahead and try it for myself. After ...
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60 views

Rubber insides and circuit transparent sheets of USB keyboard don't work outside of plastic case

I have very little knowledge of electronics and circuits, so I apologize in advance if the question is dumb. I couldn't find answer anywhere. I am trying to remove plastic part of my keyboard and ...
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40 views

How to connect rows and columns in a keyboard matrix

I want to build a keyboard from scratch, so I started by designing the schematics. I have found several ones on the web in which the switch - diode direction is connected from row to column, and ...
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1answer
134 views

Building a keyboard matrix

I want to build a 7 Rows x 15 Columns keyboard from scratch, thus I have started from the theoretical design of the matrix. The classic way should be to assign directly the Rows and Columns to (7+15) ...
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Keyboard matrix and its microcontroller type

I'm planning to make a custom 108 keys keyboard from scratch. Unfortunately, I'm currently stuck in a circuitry situation. Is there a lean matrix that I can go with for this and what kind of ...
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110 views

Rapidly driving a keyboard signal

My goal is to build something that simulates rapidity (50 to 1k Hz) pressing a key on a USB keyboard. My first inclination was drive a transistor from a 555 timer with the two keyboard matrix pins on ...
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1answer
170 views

Arduino emulating a keyboard that has a demultiplexer

I have a old typewriter which I want to automate with an Arduino. The way I am trying to do it is to replace its keyboard with the Arduino and make the Arduino emulate the keyboard i/o. The keyboard ...
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1answer
136 views

Messages sent when keyboard key is pressed [closed]

When pressing keys on a keyboard what messages are sent to a PC? Is it OK to send this message using a micro controller (through USB cable)? This is the protocol format i got from website. how to ...
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1answer
119 views

Malfunctioning atmega32u4 split keyboard — help diagnose

I purchased this split keyboard kit called a gergo and assembled it myself. The board properly registered via usb so I flashed it with qmk which has very good support for atmega32u4 and several ...
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6answers
296 views

Do Computer keyboards have ICs?

I have always assumed that computer keyboards do not, in the typical case, contain integrated circuits. And also, now that I think about it, there must be a set of standard electrical (digital?) ...
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2answers
116 views

How to connect a microcontroller to PS/2 port as the PS/2-keyboard?

The voltage of output signals of my CPLD MAX II board is 3 volts. Can I connect this board to open collector of PS/2 motherboard-MCU? So, if I want to send a "zero" signal, I'm sending "one" to the ...
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119 views

Old 8 bit decoder behavior

I'm trying to add an USB keyboard to an old 8-bit Amstrad CPC 464 home computer, like is done here. To make a brief summary: The keyboard is designed as a matrix with 10 lines and 8 bits per line, ...
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What linear sensor for a keyboard? [closed]

I'm trying to make a velocity-sensitive keyboard for playing music. I have to measure the position of each key in order to know how loud the sound should be. The volume of the sound is a function of ...
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1answer
376 views

Single key not working on DIY mechanical keyboard (xd75re PCB and Switch both work)

I have assembled my first mechanical keyboard using the xd75re PCB. I used a plate mount, and all of the switches were installed without issue (this PCB has hotswap). When I used keyboardtester.com to ...
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185 views

How did the Commodore 64 keyboard work?

I'm designing a computer using a Z80 processor (I know, not the same as the one the C64 used, it doesn't matter) I found the following schematic showing part of the C64 circuit, and I'm particularly ...
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3answers
251 views

USB hub inside modular keyboard for comunication

I'm working on a personal project which consists on a keyboard that also serves as a hub in order to connect more keyboards. For example, I could have the main keyboard with the letters and symbols ...
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1answer
132 views

What kind of led would be used for this keyboard [closed]

I have a project that involves this keyboard, it has 12 sections on the pcb marked UX (X being 1-12) for what I guess are for leds. If I'm correct what kind of led would I buy for it? Something like ...
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2answers
295 views

What connector did this IBM Model M keyboard have?

I got got hold of an old IBM Model M (Model 1391403, to be precise). Unfortunately, the fixed cable was cut off by an unknown idiot. Does anyone know what kind of connector (I assume PS/2?) was ...
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1answer
65 views

Understanding replaced leds brightness behaviour (keyboard backlight)

I've followed this tutorial to replace some broken leds on my keyboard. The leds I used are: ...
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1answer
611 views

Is there a way to add Bluetooth functionality to an ErgoDox EZ keyboard?

It would be nice to have some sort of mini-USB accessory that could bluetooth-enable an ErgodoxEZ keyboard. I found some related discussion here: https://www.reddit.com/r/ergodox/comments/8kugs5/...
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113 views

Using a micro computer as a macro keyboard device?

not entirely sure this is the best StackExchange board but I bet some of the great members here could at least point me in the right direction. I'm looking to use one of the microcomputer devices, ...
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1answer
148 views

Using connected PC keyboard input for VHDL Simulation

I am working on a project for school that will involve an input from a push button or related device. We have only a few Spartan boards available, but we have access to Xlinx Vivado to simulate an ...
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1answer
81 views

how rubber keypad works [closed]

Press on the keyboard, how does he connect the circuit of this key? Two thin films, coated with conductive rubber circuit, with a thin film in the middle, with holes, used to isolate two thin films ...
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2answers
59 views

how to mount a flat keypad on a panel

Flat Keypad or Membrane Keypads are cheap and beautiful Keyboad that can be used in systems. but the question is how can they be mounted in a box or panel?
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1answer
133 views

How does this N-key-rollover work?

I'm designing a keyboard. I found some information online about how to make the keyboard be able to detect multiple key presses at the same time (N-key-rollover). I found this schematic, from this ...
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2answers
898 views

Laptop keyboard backlight ribbon cable broken [closed]

I've accidentally broke my laptop keyboard backlight ribbon cable when disassembling my laptop. I want to solder it back by patching with copper wires or maybe copper plates. My question is, it is a ...
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2answers
72 views

Keyboard wireless feedback from computer

This is a theoretical question. I want to ask, is the the modern keyboards communicate with PC such as wireless keyboards can 'get/read' some data from the PC? If not, what do I need to do for that? I ...
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1answer
159 views

I need to do a membrane pcb for a keyboard or a flexible PCB like a membrane PCB

I need to design a membrane PCB for a keyboard and/or flexible double sided PCB that works like a membrane PCB. My problem here is that I don't know how to do the buttons, with one contact of the ...
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1answer
85 views

USB HID keyboard: why 4 URBs are generated for a keypress instead of 2?

This is system log when keyboard is plugged in: ...
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1answer
649 views

What microcontrollers are suitable for a keypad [closed]

I'm a beginner in electrical engineering but I'm into mechanical keyboards and I want to build a keypad (1 row, 6 cols). I recently wrote a macro for a keyboard (ATmega32U4 microcontroller) using the ...
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0answers
129 views

Why short 3 terminals per contact on a membrane keypad?

What is the purpose of a three-terminal momentary contact in a matrix keyboard? The motivating example is that I have a damaged membrane keyboard where some of the keys do not work. At first I ...
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1answer
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water-damaged 3DS, some buttons are now non-functional, any ideas? [closed]

so about 3 months ago I got my Nintendo 3DS wet. I tore it down, cleaned it up with isopropyl alcohol (of highest possible purity) and let it dry off. unfortunately for me, there are some buttons ...
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1answer
203 views

i2c interference on coiled wire

Hello good day I been trying to build split keyboard using 2 pro micro. I'd been following let's split keyboard using qmk firmware. And the connection diagram of the i2c is this When doing it on ...
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1answer
752 views

Wake up ESP-32 using matrix keypad

I want to realize a wireless keypad using ESP-32 and a matrix 4x3 keypad, connected via Bluetooth Low Energy to a master unit. I want to use deep sleep mode of ESP-32 when the keypad is not used but I ...
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2answers
709 views

What is this keyboard connector and how to connect it to MCU?

I have a 1991 laptop keyboard w/o the motherboard. It was attached to the main board with two flexible cables. The keyboard feels awesome and I would like to make use of it. The issue is that I can't ...
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1answer
116 views

Sony vaio keyboard dongle - Power issues connecting to another computer

I have stripped down a very early (2002) vaio all-in-one desktop which has a keyboard with a built in protective cover which I would really like to use on another computer. The dongle was placed under ...
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1answer
72 views

Protecting handmade electronics from accidental water spillings [closed]

Keep in mind that I dont know the least about electronics. I have soldered and used some arduinos before, but that is it. I am preparing to make a mechanical keyboard (or handwire like they say on /r/...