Rotary encoder/UP DOWN converter

[junglejet]

Hi,

as a spin-off from my cockpit project I have developed an interface chip that converts rotary encoder signals to something easier to use.

Rotary encoders usually come with a quadrature output that is difficult to interface to other platforms.

My solution is a small DIP-8 microprocessor that is connected to the two outputs of the encoder (no external pullups required). The internal logic converts the quadrature input data to three outputs:
- /CLK = active low for 1 ms when the encoder was turned in either direction
- UP = active high for 1 ms when the encoder was turned right
- DOWN = active high for 1 ms when the encoder was turned left

E.g. a counter unit can much easier process the /CLK, UP and DOWN signals to control a frequency, heading, altitude selector etc.

Interface is between 1.8V and 5V, fully CMOS or TTL compatible. A block capacitor of 100 nF is recommended close to the VCC terminal.

I can make the chip available for private use if there is sufficient interest to burn a couple of them. Price would be around 5€ per piece, in quantities less, p&p to be added.

Please drop me a pm or post below if you are interested.

Andy

[nricky]

Hi Andy

That sounds great. The best voltage would be 5 Volts. How would you guess in how much the will cost and for how many encoders it will run.

Please tell us more. Great idea.

Cheers Norbert

[ian@737ng.co.uk]

hmmm.... now this sounds interesting...
i'd also like to know a bit more about this too. can you go into a little more detail about what you have achieved using this chip.
thanks in advance and regards ... ian

[junglejet]

Hello,

I have used the chips to poll four encoders through an old notebook's parallel interface. The chip converts the encoders quadrature phase output to a DN and UP signal. When DN or UP is seen high on the parallel interface the notebook increases/decreases COM1/2 frequencies (Data are then sent out via ethernet, but that's another story).

So basically you can use any computer or microcomputer board that can poll or react to an interrupt to process the encoder output without any weird logic like monoflops or so.

For the complete parallel interface in the example it needs four encoders and four chips, i.e. it needs on chip per encoder.

We can easily adjust the output signals according to your needs by software. For now 1ms pulses were sufficent, but we can go for 10 ms or invert the signal or do any other scheme.

You can use any voltage between 1.8V and 5V.

I will develop some more complete documentation and sample drawings and post it here as soon as I can.

For quantities over 20 I would think the price is half, over 50 even less. It depends how cheap I can get the basic chip.

Another option by the way is the spin warrior USB converter chip. But this was too expensive for me.
http://www.codemercs.com/index.php?id=43&L=1

Andy

[Jackpilot]

Chinese to me...but could this be used to drive dummy Flight alt and Land alt displays.

[ian@737ng.co.uk]

jack.....
this is exactly what i have in mind ))
good one...rgds ... ian

[junglejet]

Can you point me to what's inside these dummy units?

Any reference docs available?

Thanks
Andy