Minions Turn Your Keyboard into a Bluetooth Keyboard

Evil geniuses usually have the help of some anonymous henchmen or other accomplices, but for the rest of us these resources are usually out of reach. [Evan], on the other hand, is on his way to a helpful army of minions that will do his bidding: he recently built a USB-powered minion that turns a regular PS/2 mouse and keyboard into a Bluetooth mouse and keyboard.

[Evan] found his minion at a McDonald’s and took out essentially everything inside of it, using the minion as a case for all of the interesting bits. First he scavenged a PS/2 port from an old motherboard. An Arduino Nano is wired to an HC-05 Bluetooth chip to translate the signals from the PS/2 peripherals into Bluetooth. The HC-05 chip is a cheaper alternative to most other Bluetooth chips at around $3 vs. $40 for more traditional ones. The programming here is worth mentioning: [Evan] wrote a non-interrupt based and non-blocking PS/2 library for the Arduino that he open sourced which is the real jewel of this project.

Once all the wiring and programming is done [Evan] can turn essentially any old keyboard and mouse into something that’ll work on any modern device. He also put an NFC tag into the minion’s head so that all he has to do to connect the keyboard and mouse is to swipe his tablet or phone past the minion.

If you’re looking for an interesting case for your next project, this McDonald’s Minion toy seems to be pretty popular. PS/2 keyboards are apparently still everywhere, too, despite their obsolescence due to USB. But there are lots of other ways to get more use out of those, too.

22 thoughts on “Minions Turn Your Keyboard into a Bluetooth Keyboard

  1. Obsolete due to USB, amusing. They are software and electrically compatible. Just change the plug or add an adapter and you’re good to go.
    [ probably a little more secure than broadcasting your keystrokes over bluetooth. ]

    1. What? No. Some keyboards’ controllers can speak either PS2 or USB and thus can work with a passive connector change, but it’s device specific and certainly not a universal standard.

        1. The tiny ones that come with (or came with, if nobody makes PS2 boards now) keyboards are just passive adapters. The controller in the keyboard electronically reconfigures itself depending on which port type it detects its plugged into, or could be a little something in the USB to PS/2 adapter that makes the board reconfigure. That would require some bit of active electronics just to kick the board over to PS/2 mode.

          Anyone have one of those little green Microsoft USB to PS/2 mouse or keyboard adapters to sacrifice to find out?

          Some of those dual purpose boards are troublesome with some computers. Either they don’t work until after POST configures the hardware, or they work to get into setup, then for some reason quit working, can’t even ctrl/alt/del to reboot.

          Using them on even older PCs can be a problem, if the A20 setting is not switched to onboard. Got an even older one that has no onboard A20 capability? Then it’s likely you’ll be stuck scrounging for an old AT keyboard or early PS/2 one and an adapter.

          There’s one for a retro tech article on the A20 line. https://en.wikipedia.org/wiki/A20_line especially if it goes into more depth about what was changed from the PC and PC/XT keyboard and why some newer keyboards don’t work on older computers. Interference or lack of something in the keyboard???

  2. Evan AKA Frankenstein modified Kevin’s asshole, gave him a brain sensory input. So Kevin’s a moster then. I’m no fan of hot glue because in my experience no matter how much is used it will fail often. Because it was use than it where be the device will be subject to regular mechanical use, I fear for the longevity of one of Kevin’s implants. While a bit fast paced Evans video production of the project was excellent.

  3. Awesome! I’m not in a position to watch the video now but I am excited to do so later. I have been planning on using a usb host adapter and a bluetooth hid dongle to build a USB keyboard/mouse to bluetooth adapter. My purpose is to use it with my old Lapdock so going PS/2 isn’t really an option.

    Anyway.. I’m eager to see how he uses the HC-05 for keyboard and mouse use as that would be a big savings over getting an HID dongle. My understanding was that those chips are capable of all sorts of different bluetooth communication modes but the cheap ones we find online are all set to be simple serial devices. I though changing that required spending big bucks for a programmer and signing an NDA.

    1. programmer is not expensive. There are USB programmers that repurposed from CSR audio modules using similar idea, around $10.
      Leaked IDE can be found on Internet.
      However, license to access documents is expensive.

      1. The official CSR programmers were *ridiculously* expensive – a thousand dollars or more. Which is a complete rort.

        The unofficial programmer that uses the CSR modules isn’t a good solution nowadays – you need to find exactly the right old hardware, and you still need another programmer to reflash it in the first place.

        The easiest path is probably https://github.com/Frans-Willem/CsrUsbSpiDeviceRE which lets you use a $10 stellaris launchpad as a programmer (I’ve used this successfully).

    2. Basically you dump the firmware from the RN42-HID module and flash it to the cheap one. I’ve done it, it works well. However you do need to fork out for the more expensive module to start with (it’s not legal to distribute the firmware dump.)

      Making the adapter to handle USB devices is tricky – either you need a microcontroller that supports USB host mode, or use a USB bridge chip like the CH376.

  4. Great project. Since you have experience I wanted to share just an Idea. I know it’s complicated, but I am interested in your opinion.
    I always wanted to connect 2 physical computers like they are one. For example if I need to transfer something from laptop to desktop computer I though that it would be nice to plug a USB device into each and have a mouse that could be controler on both via this two USB devices. You could select, copy, transfer data from one to another and also used both at same time.

  5. PS/2 is obsolete. It is still very popular with the gaming community and can be found yet on many new higher end motherboards.

    PS/2 supports n-key roll over and has (generally) fast scan intervals, these are issues of concern to gamers.

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