Programmable digital knock filter?

[barana]

Festy,
I've located some hip9011's from hongkong, https://m.ebay.com.au/itm/1PCS-HIP9011A ... 6a8c96768c Ive purchased 1 for myself, would you be willing to sell me a board or two with everything minus thehipchip?
If not I know my way around an iron,https://m.imgur.com/eTiIEJl would you be willing to sell me the bareboard ?
Im willing to locate my own components/MCU board from a parts list.

[vlad01]

Found this a little while ago but only got around to posting it now, it's tuned to the bore upon ordering and is very affordable, unlike most aftermarket knock units these days.

I know this isn't as sophisticated as Festy's original filter board, but does anyone think this could work or be made to work with the 808 with the 5v output this uses?

https://www.viatrack.ca/

[hjtrbo]

Wow, nice find. And they're saying it's fine to run a y-cable to tee off the existing knock sensor with their 'dual use' setup. Nice!

[immortality]

Interesting.

[antus]

Not sure if its compatible. I cant see anything about how it works on the page. I think the 808 is a digital logic signal, the longer its high, the more knock counts the ECM counts. So in theory if it was a 0-5v output you could probably build some basic switching circuit for sensitivity to set the voltage which the ECM sees a logic high, and that might work. These days with such cheap MCUs around, I wonder if it would be possible to connect the sensor to some cheap off the shelf MCU and band pass the signal in software to make tunable knock sensor, then output the digital signal for the 808? You might not even need the kit above. Would probably depend on the sampling speed of the ADC in the MCU. Most half modern cheap MCUs would probably be able to run a software FFT to decide if its hearing knock if it could sample the signal fast enough to cover the audio frequency.

Also even though they are obsolete digikey is showing obsolete they are also showing loads of those HIP9011 chips at the moment, so the biggest problem is there is I dont think there is anyone to make the sensor around it.

[vlad01]

The way I read it, it's a 5v digital output, so it might work.


With modern chips, I assume one could design a drop in board for the knock filter so it takes up the same footprint, thus avoiding having to solder the board to the main PCB? I would love to have something like this. The factory knock filter is as useless as they get in my experience and so I just turn it all off.


Do we know what happened with Festy's original design? or Festy for the mater of fact?

[antus]

if it is a 5v on while above threshold type signal, then yes it probably would.

Yes, even with old school tech you could probably fit the same footprint.

Im not sure how much of the factory knock sensor being useless is because of the signal though. I guess if you had something smarter delivering the on/off signal then better would be possible. If you still had a band pass filter and not much else, it'd probably be the same.

I happen to have one of the original design on hand, but I havn't seen festy around here for a long time.
It looks like a pic mcu to use the hip9011 and probably the GPIO out for the pcm, and silabs usb board for the pc side link.

[vlad01]

So I gather new boards could potentially be built with the availability of the hip9011 being there?

You are right, digikey has over 800 units in stock and they are only 8 bucks each.

[antus]

We don't have firmware. Could engineer a new firmware, and if so its probably best to target a newer cpu too. Doable for someone who wants a project, but time and effort.

[vlad01]

I'd give it a crack if I wasn't so useless at designing and building PCBs, I could probably reverse engineer Festys hardware if I had one at hand and a program that I could get my head around well enough for the PCB layout.
I used to use a program called DXP-2004 way back when I was studying electronics, I did all my PCB design in that and it was pretty intuitive to me and was good at telling you what errors and mistakes you needed to fix, I hadn't come across any software as easy to use as that one. It was a licensed software that was very $$ iirc.

I tired a few free PCB programs over the years and never got my head around them enough to do anything useful.