For the nerds in us: Latching/Momentary/Hybrid Switch

[Marshall Arts]

I haven't built anything in quite some time, mainly because I am happy with an HX Stomp with an external DIY midi controller feeding the power amp of a trusted tube amp. So, this post is also to document that I am still around 

I was in urgent need to remotely activate/deactivate my TC Helicon Play Acoustic live. TC Helicon only provides switches without LEDs, so I build one WITH LED based on a smart switch PCB I designed like 3 yrs ago. The switch shows the urgency I was in ;-)





Now comes the nerdy stuff:
This pedal (like many others) needs a momentary switch to be activated and deactivated. My switch uses a DPDT momentary switch to directly communicate with the pedal (first half) and to interface with an Attiny85 to alternate the LED-Status. I could have used an NE555-based circuit as well, but the board was designed for an Attiny.

Here are some questions:

• Is there really no commercial pedal that works momentary on the jack and latching on the LED? Hard to believe, but I did not find one.
• The Helicon needs a TRS-cable. My Switch makes a connection between Ring and Tip, however, I want to use standard cables with TRS on both ends. I use a 9V battery for the Attiny and the LED and would like it to be disconnected  when I pull the TRS plug from the pedal. I only found the very pricey Switchcraft 13 Jack (which is mono, but that's ok) that comes with an "isolated make circuit" switching function. Are there any other Jacks available?

As I have everything more ore less in place and only some programming and PCB-redesign will be required, I will make this into a universal switch. Soft 1PST Switch communicates with the Attiny, which controls a relay and an LED. Operation modes can be toggled between the following modes:

• Jack Momentary, LED Momentary (a real momentary pedal with LED e.g. for momentary effects)
• Jack Momentary, LED Latching (what I need for the Helicon)
• Jack Latching, LED Latching (a real latching switch e.g. for classic tube amp channels)
• Hybrid Mode 1: Momentary, if you hold the button for e.g. a second or more (will go off at release of the button), Latching switch, if you press the button short (will go off on the next button press).
• Hybrid Mode 2: Same like Hybrid Mode 1, but working with pedals that only expect momentary impulses to toggle. So I can use the Harmonizer in the TC only for a few seconds (e.g. in a verse) by holding the buttons down or for longer periods (e.g. the full chorus) by switching it on at the beginning of the chorus and off again after the chorus.

The new design will have the "invert" button as well to invert the behaviour of the LED. Any other suggestions on what a switch could do before I start programming?

[Aentons]

Tails

[benny_profane]

Great work here! I'll have to think on it a bit if there's any other behavior that I could see a use for. Definitely keeping an eye out for developments.

[Marshall Arts]

Tails

Unfortunately, its just a remote, not a bypass switch. No audio signal going through this...