Jump to content

digital attenuator


kevin gilmore

Recommended Posts

So in the end, I ended up putting in more money than I wanted to in this project. I'm not too far from break-even if you count the extra parts I have.

I was thinking of selling off a couple of kits (board + parts, not assembled) for $85 each + shipping just to pull some money out of this project. I could sell off up to 4 kits.

I'm not upset if I can't since I'm sure I will use them over time. :)

PM me or Post on this thread if you are interested.

Link to comment
Share on other sites

Kerry, regarding the programing of the board, do they come pre programed or do we need to buy the arduino board to program the IC?

To use a simple pot to control the att, does it need programing?

Could you elaborate a bit more on this?

The attenuator boards don't come with processors, so you need an arduino board or something to control it. The programming is then loaded into the controller board which connects to the attenuator(s).

The boards will only work with a digital controller. You have an option of using a rotary encoder (see code above) or an analog POT to provide input to the controller board.

Link to comment
Share on other sites

I got the Arduino Uno board (part # 782-A000049) on Mouser. I would also recommend using a rotary encoder, since there are already coding examples for using one on this thread. I don't have a part number for the rotary encoder handy. Maybe someone else can supply that.

Beefy should have apart number for a rotary encoder, since he uses a rotary encoder for his Amati attenuator in his eXStatA. I bought my Amati as a kit with the rotary encoder included, so I don't know the part number.

Link to comment
Share on other sites

Beefy should have apart number for a rotary encoder, since he uses a rotary encoder for his Amati attenuator in his eXStatA. I bought my Amati as a kit with the rotary encoder included, so I don't know the part number.

Indeed. Here is the encoder I used for the Marc's PGA attenuator, and hope to use with this new board. It includes a push button switch that I may try and integrate, if I have time to learn how to program it.

Link to comment
Share on other sites

You can use pretty much any encoder with an Arduino. The code already posted will work with all "Incremental" encoders that are "2 bit Gray Code" or "2-bit quadrature code", such as the one linked to above.

I do recommend going for a higher PPR (pulses per revolution) or CPR (cycles per revolution) as possible because this attenuator has 256 steps, so at 24 PPR you will need to rotate it many times to go from 0 to 256. Also, you get what you pay for, a cheap encoder will feel cheap and they can sometimes jump around between steps. If you want to splash out, I have both of these and they are really nice:

http://ca.mouser.com/ProductDetail/Bourns/EM14R0D-M20-L064S/?qs=sGAEpiMZZMsWp46O%252bq11WaOTWrP7dyXBueE8zSLmq%252bw%3d

http://ca.mouser.com/ProductDetail/Bourns/ENA1J-B28-L00128/?qs=sGAEpiMZZMsWp46O%252bq11WcqwRcNrfIIZ3fHa2t9hjOc%3d

Link to comment
Share on other sites

Boards received! Can't wait to see it in action

Thanks Kerry!

By the way, have you thought about creating a relay based input/output selector board that matches the dimensions of the digital attenuator? That would allow to stack them up in order to minimize space and signal path. It would simplify metal work as well (less drilling).

It could also nicely benefit all the hassle of the attenuator implementation: using same power supply, and same encoding method (arduino).

Link to comment
Share on other sites

  • 1 year later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.