Tappy modification?

[Pish]

Hey!
I was recently looking at the Tappy project and looking at the associated Electric Druid datasheets to get an understanding of whats going on, after thinking it was a great project.
Then the other day I spied the Soundgas LFOMO and alarm bells rang immediately. They are pretty much the same thing.
Sorry for all these questions, i mostly build kits but have bodged stuff together in the past.

1) To add CV to say Rate, is it just a case of adding a switched jack that disconnects the +5V line and pipes in a 0-5V CV into pin 3 on the pot? Do I need to add anothing else to protect the circuit from over voltage from Eurorack gear?
2)Also, similarly can I add an expression pedal input between that and the pot that works as a variable resistor?
3)Adding clock sync in, is already detailed in the Electronic Druid datasheet. I see that pin 7 is Clock out, does anything need to be added between that and a jack?
4)I'm making the assumption that the offset switch on the LFOMO is just an on/off connecting pin 8 to 5v? What do you think?
5)Am I right in saying that the LED output on the Tappy is CV? if so, how would I invert the CV so you have an output going down whist another goes up?
LAST one 6) On the LFOMO there is a pot changing the range from 0-5V to 2-7V, i dont know what is going on here. Can anyone suggest whats happening?
Cheers!

https://www.madbeanpedals.com/projects/_folders/TapTempo/schematics/Tappy.gif

[madbean]

Hey!
I was recently looking at the Tappy project and looking at the associated Electric Druid datasheets to get an understanding of whats going on, after thinking it was a great project.
Then the other day I spied the Soundgas LFOMO and alarm bells rang immediately. They are pretty much the same thing.
Sorry for all these questions, i mostly build kits but have bodged stuff together in the past.

1) To add CV to say Rate, is it just a case of adding a switched jack that disconnects the +5V line and pipes in a 0-5V CV into pin 3 on the pot? Do I need to add anothing else to protect the circuit from over voltage from Eurorack gear?
2)Also, similarly can I add an expression pedal input between that and the pot that works as a variable resistor?
3)Adding clock sync in, is already detailed in the Electronic Druid datasheet. I see that pin 7 is Clock out, does anything need to be added between that and a jack?
4)I'm making the assumption that the offset switch on the LFOMO is just an on/off connecting pin 8 to 5v? What do you think?
5)Am I right in saying that the LED output on the Tappy is CV? if so, how would I invert the CV so you have an output going down whist another goes up?
LAST one 6) On the LFOMO there is a pot changing the range from 0-5V to 2-7V, i dont know what is going on here. Can anyone suggest whats happening?
Cheers!

https://www.madbeanpedals.com/projects/_folders/TapTempo/schematics/Tappy.gif

1) To add CV to say Rate, is it just a case of adding a switched jack that disconnects the +5V line and pipes in a 0-5V CV into pin 3 on the pot? Do I need to add anothing else to protect the circuit from over voltage from Eurorack gear?

As long as the CV is clamped to 5v max then it's fine. If more than that, you would need to come up with a modification to prevent the control from not working or damaging the MCU.

2)Also, similarly can I add an expression pedal input between that and the pot that works as a variable resistor?

For an expression pedal you want a voltage divider, not variable resistor. So, just like the Rate pot. The good news is the value doesn't matter too much. So, even if your expression pedal uses 50k or 100k the operation should be about the same.

#3, #4 - I would have to dig back into the datasheet to figure that out. I suggest just asking Tom from Electric Druid directly about this. He's on DIYSB almost every day. I've talked to him a few times over PM and he's a really nice/helpful dude.

5)Am I right in saying that the LED output on the Tappy is CV? if so, how would I invert the CV so you have an output going down whist another goes up?

No the LED is not CV in that case. The CV is the output pin (5). The transistor acts as a switch to turn the LED on and off. Or, another way to look at is as a variable resistor since it controls the LED brightness is discrete steps b/w ground and "infinite" resistance. However, you could actually do one up/one down with just a little extra circuitry. See the addendum below. I believe that will work.

6) On the LFOMO there is a pot changing the range from 0-5V to 2-7V, i dont know what is going on here. Can anyone suggest whats happening?

Can't say since I am not familiar with how the LFOMO works.

[Pish]

Big thanks for getting back to me!

1) Cheers!
2) So wire a switched jack in for the expression, yea?
3/4) Cheers I've found some bits in the cut down chip. I'll give ElectricDruid a shout too 👍

5/6) yea I had it wrong, again found what I need for CV in a datasheet, I'll ask on the synth forum on how to invert. Lost site abit. As a pedal it'll be only 0-5v but if I'm near modular gear, I have the power to offset easily.