encoder wowes

[Dave]

Nigel, After hooking up the encoder you sent me and looking at it with a scope I found it is working as advertised. I went to the ALPS website and lo & behold the documentation says it has detents on every other (2 of the 4 states) of the encoder output. That is why the encoder seems to be counting by 2 because it actually is. Attached is the waveform for the output of the encoder at the detents. The suggested connection is 5 volts thru a 10k to the switch. Then a 10k from the switch in series with a .01uF to ground with the connection of the 10k and the .01uF going to the processor. This provides a filter mechanism to counter act any switch bounce that may occure due to the nature of the rotary switch. Once again, Thanks Nigel....

Dave Purola,
N8NTA

[Macgman2000]

Hello Wallaby,

Are you posting the hardware schematic of the radio? I tinker with receivers also. I am always looking to learn something new!!!

Best Regards,
Nick
KC6SDF

[wallaby]

Hi Dave,

O.K on the encoder, did you manage to get it to go up by one, even though it has two steps for one turn? or does the cap R/C take care of this.

Yes when the receiver goes I will, it uses a commercial VCO module which is custom made so you would need to insert your own design. The front end is fairly standard, using BF998 RF and IF, BB814 varactors and toko SMD coild. The 21.4 IF has a 25 khz 8 pole filter, the receiver chip is the toko 10931V. These were chosen because they had AM, and the receiver tunes 118 to 137 mhz as well.

Cheers

Nigel

[Dave]

Nigel, With the routine I gave you it decodes all 4 states of the encoder so what has to be done is a divide by 2 on the final variable. This can be accomplished by a shift statement ">> 1".

Dave Purola,
N8NTA

[wallaby]

O.K, will try it and see.

Nigel

[G8RPI]

Hi,
just a rider,
I've been looking at the ALPS encoders and it would appear that they have a design feature that departs from the classic quadrature encoder.
The contacts require a 10K pull-up to Vdd and go low when the shaft is rotated. Rather than maintain the low state, both outputs go open when the shaft is in the detent position. This reduces the power consumption by 500uA (0.5mA) when the encoder is idle, significant power in battery operated designs. This also gives the two pulse per click characteristic. There was nothing wrong with your code.

Robert G8RPI.

[wallaby]

Thanks Robert, it sort of makes sense now and yes there is a position where it stays high, or low. They are a very reliable pot, we have used well over 6000 in our radios over the years with very little trouble.

Cheers

Nigel , VK4FNA