digital volume pot project

[digi01]

the digital volume control design that I and my friends developed together.it almost be finished.
the circuit is to utilize a programmable mcu to control a group of relays to deal the switching of R-2R mode.and it has been set up a extend interface,for using those PGA chip such as PGA2310.

here is the R/2R Ladder Networks article.
the test version used six relays.steps of switching is 2^6=256.

sch pdf file:

[digi01]

the design is finished.any comments are welcomed

pic show
1,main PCB board

[digi01]

2,LCD and remote LED setting up,I will do a test now.wish it can work fine.

[Thomas]

Originally posted by digi01

the test version used six relays.steps of switching is 2^6=256.

2^6 = 64

[digi01]

Originally posted by Thomas


2^6 = 64

Thomas,you are right.this test version is 64 steps

[gmphadte]

2^6 = 64
looks like it is 128 steps control

[jleaman]

ill buy a board.. i like the layout alot : O ) perfect for a gain clone pre-amp.

[digi01]

Originally posted by gmphadte
2^6 = 64
looks like it is 128 steps control

It should be 64 steps.
I have used six relays for R-2R ladder networks and four relays for input selecting.the mcu controls these relays through 6 I/Os.
#volume control trace:MCU(AT98S8252,eprom including)=>U6 ULN2003A(interface darlinton driver)=>relays(K1-K6)
#4 signal source trace:MCU=>U5=>relays
#mute:the control signal comes out from mcu, lead to outside interface.there is no relay for mute control on the main board.

digi

[digi01]

Originally posted by JasonL
ill buy a board.. i like the layout alot : O ) perfect for a gain clone pre-amp.

thank you
the compatible test of hardware and the strong test of software that I have already done,the result is very ideal.
here is some specification:
#64 steps R-2R ladder networks volume control
#4 input selecting
#mute
#volume state keeps after switch off
#LCD 16*2,compatibility HD44780 VFD
#infrared ray remote control available

MCU AT89S8252
Developing tools is Keil,C language.

here is the remote control pic:

[troystg]

Hey digi01-

This looks like a neat project.

Will you be offering this as a kit with all the needed parts to assemble?

If so, I'm in.

Also, when will a Multi-channel version be available?