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Numeric keypad- how to block signal? Answered

Here is the story. We needed a cell counter in out lab that counts 50 cells, most diff. counters do multiples of 100.  I found a diff counter online, altered the java script so that it counts 50cells and bought a couple of numeric keypads to use with it since the computer keyboard isn't situated well for use while we are on the microscope.  So the problem is that the two mics we used this with are set up in small room and the keypads are too close together so that if you are using one, both computers pick up the signal.  So if two people are counting at the same time the counter picks up the typed input from both keypads. 

So my question is, is there a way to block the signal from reaching the other computer?

They are both Targus Wireless Numeric Keypad.  They are wireless and use radio frequency.  I tried tinfoil that didn't work. The computers are spread out as far as they can.  That is the only room we have for them since they are fluorescent microscopes and we need to work in the dark.  I guess the obvious solution would be to just replace them with non-wireless but I was hoping that we could save money and try to get this to work.  Wired ones may be awkward to use due to space constraints too.



9 Replies

JayefuuBest Answer (author)2012-10-08

Do you need all 18 keys on each keypad?

Are you tapping ONE key for each cell you see? Or a different one depending on the cell you see?

If you are just tapping one key, you could change the javascript on one computer (with Firebug) so that it accepts the enter and change the other one to accept the 0.

OR, if you need to put an overlay over the keys for different cell types, you could tape down the + or - key depending on the keypad and then write javascript to only enter if the - for one or + for the other key plus a number is pressed. Or something similar. Kind of like chording.

Let me know if you want help changing the JS. I think if you describe in more detail what key presses you are using and with what website, we can come up with a solution.

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ChrysN (author)Jayefuu2012-10-08

Interesting, I didn't think of that approach. We are counting different probe signal patterns so we are using multiple keys, assigning a pattern to a different key. On average we use 3-4 keys but with more complex cases we could use all of the keys.
I think if you tape down on of the it will be included in the count of keys pressed.

Here is a sample of the html file that we use, I modified it to suit our lab.

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ChrysN (author)ChrysN2012-10-08

Sorry it wouldn't add the html file so I changed it to txt

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Jayefuu (author)ChrysN2012-10-08

You have ".", enter, tab and delete free.

You could write a subroutine to work with inputString so that it only enters a number if it receives key presses "."+"number" OR "tab"+"number". The function would then strip the tab or . character and enter just the number. Do you have both hands free? If so you could hold the first character with one hand then press the number with the other? Or is the idea to be able to look down the microscope and get used to which button to press for which cell type without having to look up?

If that is the case you could glue a small clamp next to the key so that you can easily release the key when you're done with each count? Otherwise when you left the inputString box the keyboard would spam your PC with characters.

This does seem overly complicated vs sending one numberpad back and buying another from a different manufacturer. You have my email address I believe from the CT list, feel free to email me if you want help with the JS.


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Jayefuu (author)Jayefuu2012-10-09

Also, if you have to go for new keypads, I'd recommend Logitech. The guy next to me at work has the same wireless mouse as me and Logitech's unifying receiver does a very good job of validating which mouse is connected to which receiver. I'd imagine you'd have similar joy with their number pad since it uses the same receiver and the software asks you to turn off and turn on devices to pair them to a particular receiver.

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CrLz (author)2012-10-08

Maybe a diffrent manufacturer would have a distinct frequency?

Barring that, bluetooth communication can have unique id's. Don't know if available for keypads. The pairing process would solve.

Switch one to infrared? Add infrared repeaters to connect line of sight.

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steveastrouk (author)2012-10-08

You can TRY screening the antennae - ground some tinfoil in an appropriate shape around the thing.

You only need to shield the PC end of things.

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iceng (author)2012-10-08

You mentioned frequency,
Is there a way to alter the frequency of one set.
Different frequencies are how remote toy cars are able to race each other.  The only review bemoans your problem.

Sorry the Targus site ;
"Unfortunately, there is no setting that will change the frequency of the wireless receiver. The best solution is to move the two computers so that they are several feet away from each other. "

They do make a hardwired version.  You can always try a Belkin keypad.


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canucksgirl (author)2012-10-08

Unfortunately no. The Targus keypad is made with one frequency only, therefore it will conflict with a second device. The only thing you can do is either move them far enough apart (specs say they work up to 30 feet away from the receiver), or replace one with another model (that will hopefully run on another frequency, or will give you an option to change channels).

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