How to use Arachnid Board as a single effect

Many__Of__Horror

Many__Of__Horror

Active member
I have a spare Arachnid board that I am looking to make into a single effect. I have programmed the effect into slot 0 on the eeprom and left the others blank, testing this in my full arachnid build it is working perfectly with every position on the 1P8T playing the effect.
The idea will be to exclude the 1P8T switch in this single effect build.

My main question is which components can I exclude as the switching effects is not required?
I have compared against the Deflector schematic thinking it is only a single effect FV-1 board and got a tad lost....Any assistance greatly appreciated!
 
The schematic shows the switching portion, D2-D10 and the 3 pulldown resistors. It uses a combination of 3.3v signals on pins 16,17,18 to switch effects. I would start by just not populating any of those diodes. The 3 pins are for binary counting between 0 and 7, so all 3 with just the pulldown resistors is equivalent to selecting program 0 (the first one)

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No hardwiring, just leave the diodes out for program 0.

The bit values on pin 15,16,17 decide which program plays.

000 = program 0
001 = program 1
010 = 2
011 = 3
100 = 4
101 = 5
110 = 6
111 = program 7

0v means bit = 0
3.3V means bit = 1

The 100k Rs pull all 3 pins down by default. The rotary and diodes work together to apply 3.3V to some of the pins based on the rotary sw position.
 
Rehashing this one as I'm getting an inconsistant outcome. When I first plug in the pedal after not using it for a while it has absolutely no effect when engaged just full dry signal. However after I unplug the power and plug back in the effect kicks in and works as intended.
I ended up excluding D2-D10 & the 1P8T switch and left all those pads unpopulated.
I also ended up putting the same effect on each of the program slots on the eeprom via SpinAsm

Would love to hear any ideas to make this more consistent in that it engages the program everytime
 
Hmm it should have worked, assuming you kept R7, R16, and R17 populated.

If the FV-1 pins are not connected to anything, they are floating and can change state (from 0 to 1) dues to electrical noise. The 100k pull-down resistors make sure the pins are solidly in the 0 state.

Even if you didn’t add the Rs, your idea to apply the same code to each slots should have worked (I’d expect some brief sound glitches if it jitters between slots, but always have the effect).

Ideas to check:
-You can check the voltage at FV-1 pins 16, 17, 18 and they should read 0v or very close.

-You could ground pin13 of the fv-1. (I would do this by hooking a wire around the leg of R5 that connects to pin 13. Then you can alligator clip this wire to ground). This would activate the internal patches that come preloaded onto the fv-1, instead the the eeprom. According the the fv-1 datasheet, program 0 is chorus reverb.

-you can check the soldering of the eeprom area. If the eeprom wasn’t installed or there was a disconnect, I could imagine this behavior. Maybe it’s random, but just seems to happen to match the timing.



The fv-1 doesn’t try to load a new patch except when it first powers up, or when it recognizes a change In the slot selection pins (16,17,18). We’ve had other discussions about using 2 eeproms on an arachnid, with a toggle. When you hit the toggle switch eeproms, the patch doesn’t change until you move the rotary switch. Your description sounds like something like that could be happening, and replugging in allows it to grab the patch from the eeprom. But I’m not sure why it doesn’t work when you first try.
 
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