Creating Wilf Rigter's ZXKBD v3

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mrtinb
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Creating Wilf Rigter's ZXKBD v3

Post by mrtinb »

Hi :)

I found Wilf Rigter's project to build an external connected keyboard like the version from Memotech.

I've found this schematic Image on this page: http://www.user.dccnet.com/wrigter/inde ... XKBDv3.htm

Unfortunately there is a component in the schematics, that I don't know: "RN1 5.1K". Does anyone have an idea what this part is?

This is my first PCB-project, and I'm trying to create the PCB.
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/Martin
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XorA
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Re: Creating Wilf Rigter's ZXKBD v3

Post by XorA »

mrtinb wrote:Hi :)

Unfortunately there is a component in the schematics, that I don't know: "RN1 5.1K". Does anyone have an idea what this part is?
Almost certainly Resistor Network!

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mrtinb
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Re: Creating Wilf Rigter's ZXKBD v3

Post by mrtinb »

XorA wrote:Almost certainly Resistor Network!
Is that a component, or just a schematic way to show multiple resistors connected?

/Martin
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Re: Creating Wilf Rigter's ZXKBD v3

Post by mrtinb »

XorA wrote:Almost certainly Resistor Network!
Ah! I found this component Image

/Martin
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PokeMon
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Re: Creating Wilf Rigter's ZXKBD v3

Post by PokeMon »

You can use single resistors as well.
The network just save space while one end of resistors are connected all together to allow easy multiple pull down oder pull up resistors in one package.

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Re: Creating Wilf Rigter's ZXKBD v3

Post by 1024MAK »

Hello Martin, welcome to our forum :D
mrtinb wrote:Unfortunately there is a component in the schematics, that I don't know: "RN1 5.1K". Does anyone have an idea what this part is?
It is a resistor network. This type has six 5.1k ohm resistors, all of which connect one end of each resistor to a common terminal (so this type would have 7 pins). As Pokemon says, they are commonly used for pull-up (to the +V rail) or pull-down (to 0V / GND). Be careful when ordering, as some have individual resistors with no common terminal. Also double check (including testing using a meter on the resistance range) which terminal is common. As putting these in the wrong way round can cause many weird fault symptoms...

If you can't get a 6 way type, a 7, 8 or 9 way type is fine (just ignore the pins you don't need. Or use normal resistors.
If you can't get 5.1k ohm, 4.7k ohm may work.

Good luck :D

Mark

PS there is a requirement to post up lots of details of your progress, including tech p0rn photos :mrgreen:

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Re: Creating Wilf Rigter's ZXKBD v3

Post by mrtinb »

On the keyboard it would be nice to have keys for cursor that enables both [Shift] combined with [5], [6], [7] and [8].

As the keys have 4 pins one set can be connected to [Shift] and the other to e.g. [5]. Image

Do I need a component that delays e.g. [5] so [Shift] reaches the computer first?

/Martin
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1024MAK
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Re: Creating Wilf Rigter's ZXKBD v3

Post by 1024MAK »

Just because switches have four pins does not mean that there are two sets of contacts inside :(
Most click type PCB mounting switches have four pins for stability.

So check carefully what the supplier says.

Or get a sample (one only) and use a multimeter to test...

See the wikipedia entry to understand all the meanings that tell you how many contacts there are and what type of operation they have.

Mark

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Re: Creating Wilf Rigter's ZXKBD v3

Post by mrtinb »

Now the PCB design is complete. The board (10 cm x 5 cm) has been ordered in China. It looks quite confusing but this is my first board, and all connections have been made with autoroute.

Now I need to order the ics, sockets, connectors, resistors, diodes and capacitor. Keyboard will be connected with ribbon cable. The 9-pin joystick port will also connected with ribbon cable.

/Martin
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Paul
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Re: Creating Wilf Rigter's ZXKBD v3

Post by Paul »

I would like to say that all power lines should be much thicker.
kind regards Paul
In theory, there is no difference between theory and practice. But, in practice, there is.

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