USB to PS/2 Convertor





Introduction: USB to PS/2 Convertor

Here i will show you a simple tutorial to convert your USB keyboard to comfortably adapt to a PS/2 connector in a computer.

The Situation
I had actually bought a flexible keyboard from the market and i had no idea that it had a USB socket to the output. I was using this USB keyboard for a couple of days and after using it for some time it was giving me trouble. Sometimes the keys did not function properly and sometimes it would automatically eject i.e disconnect from the computer port and again connect. I was having such problem and decided to find a solution for it.

The conception
After doing a bit of research i found out that most of the modern keyboards can be easily adapted to a PS/2 connector with ease. The only thing you need is just the USB socket and a PS/2 Jack (i got mine from an old mouse of mine). I also found out that when you buy a keyboard and if it is for the long run like in a Personal Computer, then it is better to have a PS/2 connector bought. Since the flaws for buying a USB keyboard are (i) It is gonna occupy one of the USB slots in your computer and hence there will be no space for USB when you are connecting multiple com ports. (ii)It is gonna use some kind of processor time since it has plugged into a USB. Very nice to have one more empty USB connector
Therefore my suggestion for you all if you are buying for a Personal Computer is to buy a PS/2 keyboard in place of USB. But again if you have already bought it then this instructables is gonna teach you how to accomplish the feat.

Step 1: The Project

Parts needed:-

Then the only thing you have to do is see the circuit diagram that i have submitted here and solder the wires according to the pins. You are then done.
Your USB keyboard will be hooked to a PS/2 converter and will work just fine.
It should also be noted that some old keyboards will not work as the parts used inside the old keyboards will not generate the required cock timings required for the motherboard to comply with it.
But most of the Keyboard will definitely work.

Step 2: Analysis and Completion

Now after you have successfully wired the USB socket with the PS/2 jack, it's time to test weather the connection were made rightly. Check the continuity of the wires.
Then finally apply some duct tapes or paper tapes to conceal the hotglue remainings so that the wire gets a rigid shape.
And finally your DIY cable is complete.



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I have a question: I have an USB keyboard and an arduino to control the keyboard. The arduino supports only the PS/2 connector. I have a USB-PS/2 converter. It not work. Can I use this to make the USB keyboard working? Thanks!


That is possible but in some cases the wiring in the mouse plug is different and you would need to change some of the pins.

If that is the case, the correction below should work.

For data use pin 2 of the ps/2 and connect that to pin 2 on the usb

For clock use pin 6 of the ps/2 and connect that to pin 3 on the usb.

Proper ps/2 connectors are colour coded, e.g. purple is keyboard and green is mouse this is reflected on the sockets on the back of the computer to make sure the correctly wired plug is installed.

Most "modern" ps/2 computers are fully wired up on both sockets, but plugs aren't.

i have a ps2 optical mouse, i want to make a USB connector for that. Is it possible to follow the same circuit diagram for that. (i have usb male connector and ps2 female connector)

man... this is great... this is what I've been looking for... Thank You.

Can I do the opposite with it i.e from Ps/2 to USB conversion

Actually for reversing you have ready made adapters available. These have 1 USB plug that will plug into the port on the PC and have 2 pigtails to accepy PS2 mouse and keyboard. Look up on or aliexpres. These are quite cheap and work VERY well.

can i reverse it ? i want to convert the PS/2 keyboard to USB ?

Nice mod sir, congrats :). I have a Saitek ST220 Digital Joystick with
an old 15 pin game port connector. Is it possible to mod it into usb?.
Problem is device driver availability. After intensive search no one
seems to have published a mod like that. Someone published an usb ball
mouse steering wheel mod very nice, and I'm thinking this mouse circuit
board could be used for the Joystick.

ha all of you are talking sophisticated, it's ironic because usually comment sections go straight to hell, occasionally come back, and plunge ever deeper into the abyss of rude language, but here the "be nice" policy seems to actually be working.

Nice Idea..

This will not work.
The PS/2 keyboard is like I2C serial device. It has clock and data lines.
The hardware inside a PS/2 keyboard doesn't have capabilities to emulate a USB HID device as a USB keyboard.
Hence USB will give message device not recognized.