When I chain my arduino shield and my footswitch, the footswitch disconnects

Hi All,

I tried to resurrect an old thread, didn’t seem to get any notice, so I’m reposting as a new thread:

I have built a device with the arduino shield to let me use a conventional expression pedal. However, when I plug it in, and wiggle the pedal, the footswitch extender disconnects (its the MOD one, not a custom one). Somebody else had this same issue here: (My Control Chain Device (almost finished)) and it was supposedly fixed by @ricardocrudo in August of 2017, but I seem to be experiencing the problem.

My footswitch is at firmware 0.2.2, my arduino code is using 0.5.1 of the Arduino CC lib.

I literally took the expression pedal example from the ControlChain arduino lib, the only change I made was to calibrate the range that my expression pedal reads (changed the maximum from 1023 to ~800).

Please help! I’m so close to finishing this project!

Same problem here.
Tried a lot of things with my The TrippleCPedal (ControlChain) pedal, but
I wasn’t able to make it work reliably…
Often disconnects when i try to toggle the switches, or doesn’t ever get recognized at all…
After some time I put it in a box and left it there unfinished…
Which is a shame, because i really put some effort into it…
Has anyone in the community ever made something, that worked fine with the arduino shield?

Having looked at some of the “fixes” in the code, I suspect the problem is that devices with pots, or encoders I guess, anything that generates a large number of updates, floods the bus, and the other controllers don’t get to send their hear beat in time. I’m going to try limiting my pedal to 60hz, and see what happens.

It didn’t help.

I have another arduino and shield lying about, so I’ll have a crack (in a few weeks, when I get back from my holiday) at chaining two arduino projects and leaving out the MOD FootEx. I suspect the problem is with the footswitch.

Hey guys, to be honest i haven’t followed up with that problem and now my device is lying on a shelf… waiting for the MOD Expression Pedal.

But at some point i will try to reprogramm it - eager to see how you can solve the problem!

@gianfranco @ricardocrudo @Jakob anybody have any thoughts?

1 Like

Hi @guysherman
I’m not experienced with Arduinos and the Control Chain. I will try to help you later but I have no time available in the next two weeks.

Sorry for reviving this thread from the dead but… Has there been any progress with this issue? I feel like one of the big selling points of the MOD Duo was control chain, and specifically that you could make your own devices for it, but if you can’t actually chain extension devices, it seems like a bit of a waste?

@gianfranco @ricardocrudo @Jakob @falkTX

1 Like

@jesse i know you’ve posted on the MOD blog about DIY Control Chain devices; have you chained any of yours successfully with the MOD Footswitch?

@guysherman i have my arduino shield and am going to be building some sort of control chain device later in the summer or in the fall and i use the MOD footswitch a lot already, so i’ll let you know how it goes for me… unfortunately, it’s not something i have time to get into right now!

I look forward to hearing about it. Near as I can make it, there is a bug somewhere in either the footswitch firmware or the arduino lib to do with message sizes, and the footswitch gets starved, and can’t send its heartbeat, so the Duo stops recognising it.

Oddly, I haven’t tried chaining them the other way round (you’d think I would have done that early on). I’ll try that later this week once I’m back in the same country as my gear.


more symptons?
My footswitch disconnects fairly often when I change pedalboards (both have footswitch assignments)
I have to disconnect/reconnect to get it back.

The control chain protocol is very picky on timings, so if a device takes too long to process the messages, the entire thing stops working (as it is a chain/series of connections)
Some off-brand arduinos dont work well, but that is almost all I know about control chain…

I agree that this issue makes control chain seem like a waste. it has potential to do very nice devices that integrate with the units in a way other specs can’t.

One thing I was made aware of, is that the arduino examples the mod team made also have issues.
So everyone that copied code did not get the best experience.

The controlchain protocol got made with with very strict timings, but it does not have to be that way…
We will try to make it better!


At the minimum a system menu option to rescan the control chain & reconnect would be nice. I should not have to disconnect power to get the Mod Duo to rescan the chain