
Dongles to Fake Presence of a Keyboard? 123
An anonymous reader asks: "I have a Compaq IPAQ desktop system (legacy free) that will not boot headless. (Yes I did try to tell the BIOS to not generate a no keyboard error, but there is no such setting for the BIOS of this system.) Since I would like to use it such and don't wish to waste a keyboard just to keep it from complaining, I'd like to come up with a small dongle that would fake the system into thinking that there is a keyboard attached. This is the same basic thing that KVM's do, so the circuit shouldn't be that difficult to find. Has anyone heard of such a thing? Can anyone provide or point to somewhere where I can find the basic circuit for this?"
How hard would it be to take the connector part from a old non-working keyboard and wiring something like this up?
Not terribly helpful, but ... (Score:5, Insightful)
You'll also have the added advantage of having a keyboard attached to machine, just in case.
Re:Not terribly helpful, but ... (Score:5, Funny)
Re:Not terribly helpful, but ... (Score:3, Funny)
Re:Not terribly helpful, but ... (Score:4, Funny)
Re:Not terribly helpful, but ... (Score:1)
Re:Not terribly helpful, but ... (Score:2)
Re:Not terribly helpful, but ... (Score:1)
Re:Not terribly helpful, but ... (Score:1)
Re:Not terribly helpful, but ... (Score:1)
Re:Not terribly helpful, but ... (Score:4, Informative)
I checked online (imagine that -- using Google instead of "Ask Slashdot"), and found this link [pcpartsleader.com] to PCParts Leader for a list of keyboards, including a THREE DOLLAR keyboard. Even after paying shipping, you're still paying almost nothing.
Do you really think, by the time you pay for the PS2 connector (assuming it's that recent, or the older connector if it isn't), and any pieces that you'll spend less than $5-$10?
If you can't afford an el-cheapo keyboard, then how are you going to buy the connector and whatever else you need?
Sheesh. An "Ask Slashdot" to replace a $3 item with something else so you don't waste that $3 item? Now I see why so many people think it's become "Ask Slashgoogle."
Re:Not terribly helpful, but ... (Score:3, Insightful)
Re:Not terribly helpful, but ... (Score:2)
Just buy a keyboard and mod (with pics) (Score:2)
Buy a couple of $5 keyboards, a really crap, silent one will probably be the best, no extra lights or anything like that.
Take them apart (there one IC and some plastic crap inside [dansdata.com], with horrible contacts and a circuit board)
There's usually just flat strip with a few contact on one corner of the plastic crap that connect to the circuit board, you should be able to pull them apart.
A page with some good pics [dansdata.com]
Now you've got a smallish circuitboard, [neontrim.com] that you can probably tape up and house inside your pc.
Re:Not terribly helpful, but ... (Score:5, Insightful)
--Mike
Re:Not terribly helpful, but ... (Score:1)
Cheap keyboards (Score:1)
A few years back I bought a brand new, 15 year old IBM keyboard for around $20. (original, sealed, old box) I wish I'd bought more, because nothing beats the feel of the old IBM keyboards.
Re:Cheap keyboards (Score:2)
He wants a box to sit there and do its thing without being disturbed by users.
Re:Not terribly helpful, but ... (Score:1, Informative)
We had the misfortune of buying about 20 similar systems (they have PS/2 ports) that are workstation class motherboards in rackmount cases and they will not boot without a keyboard attached. Since all we want is serial console access to them (we rarely even visit the site where they're installed) we don't want to waste a couple of KVMs hooking them up nor the rack space and clutter for keyboards. Seriously,
Re:Not terribly helpful, but ... (Score:3, Informative)
Here is my recommendation if you are sending the keyboard to be colo'd or something. Do what I do. Take apart a real keyboard, dremel
Re:Not terribly helpful, but ... (Score:2)
Now that spawn of Satan, the PS2 mouse, on the other hand...
Re:Not terribly helpful, but ... (Score:1)
Re:Not terribly helpful, but ... (Score:2)
And if you STILL don't want a keyboard I'm sure you could figure out how to make your own "dongle" by hacking off the ps/2 connector from the keyboard and shorting out the wires. That way when the BIOS tests it, it sees something there.
I'd test this by plugging a mouse into the keyboard port and seeing is it still boots. If so just build your own. Th
Re:Not terribly helpful, but ... (Score:2)
The keyboard is a serial device, and the BIOS sends commands to it to set key repeat rate and other default settings. When the BIOS see's no reply, it assumes the keyboard is not there.
Crossing wires in a PS2 cable will no more fool this than shorting wires on your serial port will make the computer see a modem reply to an AT command.
Re:Not terribly helpful, but ... (Score:2)
Then why does it work?
Re:Not terribly helpful, but ... (Score:2)
Seeing as AT and PS2 are serial ports, and crossing wires, without a resister will short the power lead to ground and fry something, and with a resisitor would simply register as zeros with no clock signal, I can safely say it does not work.
When you send binary data down a serial line, and the other end of the line is shorted out, you will Not get a reply back. Its as simple as that.
Re:Not terribly helpful, but ... (Score:2)
With most RS232 (and even RS422) serial ports, if you short the tx and rx pins, you wind up with a loop-back, where you receive a copy of every byte you transmit.
The parent poster wrote: Crossing wires in a PS2 cable will no more fool this than shorting wires on your serial port will make the computer see a modem reply to an AT command
This is true for two reasons:
1. Simply providing a loopback will not convince the computer that a modem is there, because a modem should reply with
Keyboards and Dongles are cheap sometimes (Score:4, Interesting)
However that doesn't really address the issue of avoiding having to have a keyboard inserted to boot the PC. I have been looking into this issue recently and found that an inexpensive microcontroller can reproduce keyboard signals quite easily. The Atmel AVR Tiny11 sells at DigiKey for $0.41 each in quantity 25 and $0.56 in quantity one. It's an 8 pin DIP that runs at 1 MHz with no external parts. Its Flash memory holds 512 instructions and it has 32 registers. The companion chip, the AVR Tiny 12, sells for $1.10 quantity 25 and can be programmed directly from the PC parallel port. The PIC controllers from Microchip Inc. have devices in the same price/performance range, but they are more difficult to develop software for and they need external programmers to write the code into their Flash memory.
It's necessary to know what bytes the PC sends to the keyboard on power-up and what the keyboard sends back to the PC. Then these bytes can be formatted by the dongle and sent to the PC to mimic a keyboard.
The PC keyboard has weird programming. Each key sends at least one byte when pressed and some send two or more. When released the same byte set is resent preceeded by the byte 0xf0.
Now any Slashdotter, when given the job of encoding a keyboard with less than 128 individual keys, would assign a 7-bit scan code to each key with the high bit either set or clear depending on whether the key was pressed or released. Simple and elegant. But the standard PC keyboard has this strange multibyte configuration that makes it difficult to decode the keypresses. Not to mention that there is no way to turn off the auto-repeat for the entire keyboard.
Nevertheless, the keyboard scancodes are standardized throughout the world. And there are hundreds of millions of keyboards out there. The newer ones only use about 13 milliAmps of power.
I developed an AVR program to take the PS2 keypresses and mimic a MIDI keyboard by sending note on/off messages according to the keypresses. I'm surprised at how well it works. Except for a few key combinations that don't register together, the PS2 keyboard can function like a MIDI music keyboard (without velocity and aftertouch detection, of course). For a few dollars, I have a small light portable keyboard that plugs into a tone module and adds hundreds of musical instrument sounds to small music group jams. This application is posted on www.avrfreaks.org in the user projects section of the Academy forum.
You've completely missed the point (Score:2)
The point is not to be cheap. The point is to prevent local access.
Re:You've completely missed the point (Score:1)
Where does he say he wants to prevent local access?
Might not be so easy (Score:3, Insightful)
so you might aswell solder the chip free from a keyboard and stick it with a plug in a housing. BTW, if you are asking this correctly the system is NOT legacy-free, legacy-free would mean no PS/2 plugs.
Re:Might not be so easy (Score:2)
he never specified that there was PS2 is on a system. the bios will check even for usb keyboards and complain of one not being there. the fact that he says it's an old IPAQ is enough for me to believe in common sence that there are ps2 ports and no usb.
but that's just be being a nit-pick.
just take an old keyboard and take out everything and leave the circuitry encased in a RadioShack platic box (very small, palm sized) and leave it in the back of the computer.
done
Too simple (Score:5, Insightful)
Re:Too simple (Score:5, Informative)
Let me expand on this -- since I've investigated keyboards for a related project.
If you take apart a keyboard, there is usually a small circuitboard/chip in the upper right/middle of the keyboard, near where the cable comes in. This is the keyboard encoder. Its roughly, oh, say about 2"x1".
The rest of the keyboard is the casing and a few plastic membranes with traces for the keys. The keys on a keyboard form a matrix or grid, with, say, 13 inputs on each side. The top of the grid may be inputs A-M, and the side of the grid may be inputs 1-13. When a key is pressed, the two membranes meet at a junction of the grid, bridging the inputs. So pressing the 'b' key might bridge F-2, pressinig 'o' might bridge A-12. Rather nifty.
The encoder transates the grid junctions (A-12, F2, whatever) into key codes for the computer. When no keys are pressed, there are no grid junctions (ergo, none of the inputs are bridged/closed)
Therefore, to make a home-made dongle, take apart the keyboard, throw away the plastic membranes and casing, and put the circuit-board and most of the cord in a project-box from radioshack. Ergo, one keyboard dongle, no soldering.
If you are feeling adventurous, cut the cable down to 2" or so and resolder the keyboard.
If you have more money then time, why not google for "keyboard encoder". The KE18 model is $45 dollars, and is about 3"x2".
It exists (Score:5, Informative)
(link in Danish. Product #2.
Standard answer: Google/Froogle (Score:5, Informative)
Re:Standard answer: Google/Froogle (Score:1)
Re:Standard answer: Google/Froogle (Score:2)
crap, did I just do that?
Re:Standard answer: Google/Froogle (Score:2)
I've found this to be the case with unusual items. If there's some obscure thing you want, odds are there is some place that sells exactly what you're looking for, but the price will be about 5 times what you feel it's worth.
RTFI (Score:2, Insightful)
Daniel
Re:RTFI (Score:3, Funny)
Re:RTFI (Score:1)
I took me a while, but I finally worked my way to the end. [1112.net] Can I go outside now?
Re:RTFI (Score:2)
Re:RTFI (Score:2)
Which isn't to say there isn't good Ask Slashdot's, they are just so few and far between these days.
Replace the BIOS (Score:2)
Re:Replace the BIOS (Score:1)
LinuxBIOS has one Compaq machine in their list. Not only is it not the one that the person posting has (it's an Alpha), it's also unsupported.
OpenBIOS's main page includes the following quote: "Jens Axboe wrote an IDE driver for OpenBIOS. This will help OpenBIOS to boot on real hardware soon."
That's from January of this year, so I wouldn't hold your breath.
Get a cheap keyboard (Score:1)
I'm usually one of the first in line when it comes time to try and make something, but this request seems like too much bother compared to the alternatives.
No one has mentioned yard sales? (Score:3, Insightful)
My cool story on t
No one has mentioned stealing one? (Score:2)
Re:No one has mentioned stealing one? (Score:1)
Did you try a bios upgrade? (Score:5, Informative)
I have run into the no-keyboard-present error when trying to convert an old desktop machine into a headless file server.
A bios upgrade gave me the ability to ignore the keyboard error.
Perhaps you should investigate that first.
Re:Did you try a bios upgrade? (Score:2)
I had a similar problem once (Score:4, Insightful)
I had a similar problem when I was given a computer, although it had to have a mouse also. Nevermind the fact that I was putting OpenBSD on the machine to be a dedicated web/mail server and didn't have any plans to install anything that needed a mouse
What I ended up doing was just getting a cheap mouse, coiling it up around itself, and throwing it behind the tower
Simple Circuit (Score:5, Informative)
Re:Simple Circuit (Score:2)
I doubt this will work. The PC "Keyboard BIOS" is really a small microcontroller (some 8XXX CPU, embedded into the chipset in "modern" machines), that communicates with another microcontroller inside the keyboard (often also an 8XXX or 6502, or a special chip in "modern" keyboards). Both microcontrollers use a crude semi-bidirectional serial protocol with a clock and a data line (For the ugly details, ask IBM or Google).
+5V is usually supplied to the keyboard trough a fuse (rated with up to 2A, often using
I confirmed this evening that this does not work (Score:2)
I stopped by Frys on the way home and picked up a baggy of 10k's and a pair of 6 pin mini dins and gave it a shot. I made two of them (just in case I flubbed the soldering in my excitement for cheap keyboard fakers). Neither one worked on systems that I turned on the 'halt on all errors' option in the bios. I tried turning off the 'turn on numlock on boot' options and this didn't m
Using old parts ... (Score:5, Informative)
Way 1:
Get a working receiver for a cordless keyboard. You do not need the actual keyboard, or a mouse. It also does not matter wheater it works with infrared or radio. Plug it into the computer. Finished. (If you are paranoid, you wrap a radio receiver into grounded tin foil to build a faraday cage, thus eleminating all incoming transmissions from wireless keyboards around. For infrared, some layers of duct tape across the infrared receiver should be sufficient, but tin foil will also do the job.)
Way 2:
Get a really, really, really cheep, but working keyboard (at least one key should work as expected). Open the case. Use brute force if needed. You should find a small printed circuit board (PCB) with one chip and three (or more) LEDs, it should be connected to a keyboard matrix made mostly of transparent foil. Rip off the keyboard matrix, throw away everything except the PCB and the keyboard cable. Place the PCB in a small case, or wrap it into duct tape. Connect the keyboard cable to the computer. Finished.
(Note: If you are really out of luck, the entire keyboard IS a PCB, or even worse, the entire keyboard is made of plastic foil, including the part carrying the chip and LEDs. In this case, getting another keyboard is the easiest way.)
Tux2000
simple (Score:2, Insightful)
2. Boot computer
3. Whip out keyboard
4. Don't turn computer off
simply a bad idea (Score:2)
Re:simply a bad idea (Score:2, Funny)
Re:simply a bad idea (Score:2)
It quite sucks.
Re:simple (Score:1)
Alternative idea... (Score:2)
http://www.linuxbios.org/
That might be a fun thing to do
Nick...
Re:Alternative idea... (Score:2)
Read another way... (Score:5, Funny)
Re:Read another way... (Score:2)
Open source BIOS. (Score:1)
Personally I've never tried it, so I'd like to hear how it goes.
Keyboard Emulator cheap (Score:2, Redundant)
SD
If you're an electronics hobbyist... (Score:1)
You're likely to end up with a spare I/O port on that 8-pin microcontroller, so you could expand the design to include a button that sends ctrl+alt+del (or, for linux, alt+sy
Strip a keyboard (Score:2, Informative)
Just a little cable hanging in the back of the pc.
Similar Question (Score:2)
I was thinking about a similiar idea, that involves USB. I've been looking for information on how the computer recognizes USB devices. Is there a circuit in there that sends some unique identifier to the system? Where is it, and what do the strings look like that it sends to the computer? Does anyone have any information on this sort of thing? I have tried google searches BTW, but I can't find anything specific regarding to the identification of USB hardware.
bios patch (Score:2, Informative)
Re:bios patch (Score:4, Informative)
I found this on the ipcop website.
ftp://ftp.compaq.com/pub/softpaq/sp0501-1000/sp
"Some Compaq machines allow the user to select this mode of operation by selecting "Network Server" mode in their setup program. For those that do not have this option, NO_F1.COM is a DOS based program that is run one time which sets a bit in CMOS that instructs the BIOS not to wait for a keystroke after displaying the "Press [F1] to continue" message."
"May the schwartz be with you!"
Re:bios patch (Score:2)
Right, this tool sometimes works. Especially if you own an ancient 386 or 486 Compaq that does not offer the user interface to set the network server mode flag. But it won't help you with modern Compaqs, they lack the matching BIOS. Quoting the embedded documentation:
Easy solution (Score:2)
http://www.solutions-cubed.com/solutions%20cube d
$30. Connect to keyboard port (These are AT, so you may need a $2 PS2->AT adaptor)
These units are designed to take input from a 4x4 matrix keypad, and you program them to send keycodes. Just skip that step. It will handle pretending to be a keyboard that never sends anything.
You can also wire up a keypad to perform 'shutdown' 'reboot' etc features if that would be handy and not a security issue for you.
Re:Easy solution (Score:2)
Neat.
Does that mean tha
Look in the Bios? (Score:2)
Since most rackmount systems now are just ATX boards in a rackmount case I would not think this is all that of an uncommon option. Look and you may have a no charge fix for your problem
A handy tool. (Score:1)
Re:A handy tool. (Score:2)
Re:A handy tool. (Score:1)
aadfsf (Score:1)
Get a USB to PS/2 converter and stick a resistor into one or more of the PS/2 holes, that will probably trick the computer into thinking there's a keyboard there. Though I may be totally wrong
PC Weasel card (Score:1)
Nothing to hang out of the back. Been around for awhile and is well thought of.
Re:Troll? (Score:2)
IR works for me (Score:2)
I picked up one from CompUSA a few years ago for about $20. The keyboard has since died, but the base still works fine for my server. Remember, the keyboard quality doesn't matter here. Who cares if the wireless has a range of two feet if you don't want it for its wireless abilities?
IR has the advantage of allowing keyboard
Easy solution. (Score:2)
To recap, buy a cheap wireless keyboard. If you do it Eeeeeeeee-bay, watch for shipping charges.
A Wireless Keyboard/Mouse is the Answer! (Score:2, Interesting)
Then, I strolled into CompUSA and saw this Wireless Keyboard and Mouse Combo [compusa.com]. The PS2 connectors stay plugged into the machine and the (nice, UFO-shaped, blinking-light) receiver stays duct-taped to the top of the machine.
All I need to do is remember to take the keyboard and mou
A historic note (Score:1)
Motherboard Wiring (Score:1)
My god (Score:2)
Just tear up an old keyboard for the driver chip (Score:2)
A couple of times i've just taken a power screwdriver to an old keyboard, pulled out the little circuit board with the LEDs and driver chip (usually these are a bit smaller than a 3x5 index card) sandwiched between two of the aformentioned index cards with a couple of holes for the LEDS, and wrapped the whole sucker in clear packaging tape.
This gives all of the benefits of a dongle, plus you can
use a microcontroller (Score:2)
KVM dungles (Score:2)
I also found this [raritan.com.tw] on a good old google search. The APKME adapter seems to be exactly what you are looking for.
A Desktop KVM switch is a lot cheaper, but it might be a bit unsightly.
Cheap ass way (Score:2)
Works on most motherboards. Occassionally you'll find one it won't work with, but with the vast majority of them it works fine.
USB - PS2 keyboard adaptor (Score:1)
All I ever needed to know... (Score:2)
Sometimes, you don't WANT a keyboard (Score:2)
However, there are circumstances where you don't WANT a keyboard hooked up: to prevent keys from being pressed inadvertently or by unauthorized people; to save space; because mgt. won't accept a homebrew project; or maybe to prevent keybo
Compaq CAN be keyboardless! (Score:3, Interesting)
There is a hidden setting in most compaq bioses that lets you boot headless.
Take the following steps:
- go into the bios
- set a power-on password
- a new option will appear, probably "password options"
- here you can set "Network Server Mode" to enabled
- reboot, remove keyboard and behold!
Good luck.
Use for old PS/2 Mice (Score:1)
Maybe it's not the answer you were looking for, but at least you get to put that old ball-mouse to use again.
Re:Use for old PS/2 Mice (Score:2)
Re:Use for old PS/2 Mice (Score:2)
Re:CueCat (Score:1)
While reader devices like this do speak the protocol, they are intended not to interfere with normal keyboard operation, and thus disconnect themselves from the data line when not active. When you scan something, it cuts the real keyboard loose, attaches itself, transmits the scanned data as if you were typing it out, then disconnects and reattaches the upstream device. This also allows you to A) stack multiple readers (ie. barcode + c