RelayISOx16 Problem enabling relay, enables all relays

Dear All,

I have a Problem with my RelayISOx16…
if I enable one relay all other relays enable itself (but only by 230 voltage)

first part of the video with 230V
second without any voltage

see Video!46295

someone any idea?


Same issue?

Welcome to the forum.
Could you please paste some of your code


Here is the code.

Thread readings;
void ProgramStarted()
            Modules added in the Program.gadgeteer designer view are used by typing 
            their name followed by a period, e.g.  button.  or  camera.
            Many modules generate useful events. Type +=<tab><tab> to add a handler to an event, e.g.:
                button.ButtonPressed +=<tab><tab>
            If you want to do something periodically, use a GT.Timer and handle its Tick event, e.g.:
                GT.Timer timer = new GT.Timer(1000); // every second (1000ms)
                timer.Tick +=<tab><tab>


            // Use Debug.Print to show messages in Visual Studio's "Output" window during debugging.
            Debug.Print("Program Started");
            readings = new Thread(ReadThread);

void ReadThread()
            while (true)


Assuming that the Gadgeteer drive is Ok it does not look like an SW issue.
Watching your video shows me that the problem only happens some times.

You should post which board you use and how Rel16 is connected. May be someone has an idea whats wrong.

My 1st guess would be that dig outs on rel16 are floating when theay are low and sometimes they drift into the high voltage when a output is toggeled.
But this would mean that the design of the Rel 16 board is bad or that it is damaged.

You could also check your 5 and 3,3V levels. If they drop under some value this might happen as well.

I have a similar experience with my ISOx16. If i trigger the relays with no load they work as expected. If I attach a 12volt solenoid valve with a 0.3 amp load. All of the leds light up on the board.

Like Randy Neal says.

Everything works great without load.
But if i have 230V attached, nearly everytime a relay is enabled all other relays enable themselves.

It feels like a coil induction of the enabled relay.
Perhaps a capacitor over the relay would help…

Any other ideas?

The other relays only change state when you try too set the first relay? And otherwise they stay in the same state?

@ Randy Neal and @ info@ - Does the problem occur with any kind of load on any of the Relays or do you only see the problem once you have connected a load to multiple relays?

I have a smaller load (12vdc about 0.1 amps or less) on another relay. It functions normally. I was able to add a capacitor across the solenoid and that has prevented the board from closing all relays and it as performed as expected with the capacitor in place.

I did notice on occasion that all relays have closed by me simply touching the ground on the Cobra. I don’t think this has occurred since I have put the capacitor in.

Sounds like the ground level is shifted and this triggers the relay drivers some how :think:

Perhaps that is the case. For now the capacitor seems to be doing the trick, so I will run with that

@ Randy for me it occours with 230V load…

  • if i have no load attached, this behavoir (“dynamically enabling all other relays”) does not occour. should i make another Video?

@ Randy Neal:
Can you please upload a photo of your Workaround?

@ Gus:
no, it is not necessarily the first relay. it seems, it’s changing when using a different amount of relays.

Thanks in advanced.

Dear Randy Neal,

can you upload a picture, where/how you installed the capacitor?


I’m sorry, but I no longer have the board. The capacitor work around turned out to be ineffective, so I am planning on replacing the board with a few digital relays. I would like to use this board as it would be more convenient but I have found no solution to the relays triggering without being signaled to do so. Hopefully someone will find a valid workaround and post their solution.

Dear all,

i have this Problem on both of mine relay platforms. Can you please help me to fix this?

Daniel Gruber

@ info@ - which main board? Do you have this problem if nothing is connected to the relays?

I ve got the spider mainboard. When nothing is connected there is no Problem. The Problem ocourse when there is voltage activated.

I thought you guys were already working on fixing this…

@ info@ - To me it sounds that the problem is caused by the load that you switch on/off and not with the io board. What kind of load do you switch on/off?