Forums & Support

Monitor Digital inputs

Any plans to include, internally or externally, the ability to monitor digital inputs?

I could rig up something for one or more of the bilge pump inputs, but plan to be using all of them!

Maybe a generic Digital I/O “extender” accessory with a few digital inputs and a few dry contact outputs?

No specific plans, but always happy to consider suggestions. Everything so far has been input only, mostly because we’ve tried to keep the underlying protocol very simple and output can lead to trouble if you don’t have very good isolation circuitry.

What other items were you thinking about monitoring? Door/reed switches and the like?

Might be faster to prototype on a Pi based system using sfh (details here) and revving the protocol to support more input designations.

Thank you for your very prompt reply!

I came from (now retired) from the Bluetooth/embedded devices/”generic” I/O product design world, so I know and feel your pain regarding this.

One immediate need would be to monitor dockside power (loss). Monitoring charging/charger output for this case is sometimes misleading when batteries reach their full charge state. Also there is a difference between failure of the charger vs. failure of input power source. I realize that alerting on low battery is the final desire here, but having the other information would be of value.

Another might be to monitor multiple HVAC systems on a large boat. Again, temperature is the final desire, but one might want to detect which unit, etc.

Other inputs may include water/moisture sensors (for non-bilge compartments) and, as you say, a hatch switch or something.

O the output side, there is of course 12V switching for any number of things – lights for illusion of occupancy, etc. Fans, time-based devices, etc. I understand how tricky output definitions/specifications are and what hap-hazard users end up really doing with them……

Having been there, I also certainly realize that this is a business decision and that you cannot support “the world”. Just chiming in though, in case there are THOUSANDS of others saying the same thing :wink:

Thanks for creating a great prodct (SUPER just as it is!) and having a great support team!

Very Best Regards,

Ray Henry

Certainly take the general point that there may be scenarios where it would be great to monitor more than 6 voltages and 3 discreet inputs. We should have a solution for more than 1 unit per vessel within the next few months, but a more generalized extender would certainly be worth thinking more about.

Thank you again for your support! I understand. Given the price point, the ability to just use a second or more of the existing hubs would easily solve most this problem.

In order to configure the desired measurement parameter (other things to measure, e.g., current, 120VAC, refrigeration thermisters, etc.) towards the existing FloatHub device’s inputs, is there a more detailed specification anywhere for the actual hardware of the voltage inputs and discrete inputs? Or a device part number that could be looked up?

Discrete Inputs:

  • Maximum voltage
  • Isolation/Input resistance
  • Specific logic thresholds for 0 and 1

Voltage Inputs:

  • Minimum/Maximum voltage range
  • Resolution
  • Relative and Absolute accuracy
  • Protection/isolation
  • Input impedance

Thank you again!

All 9 voltage inputs are really quite simple voltage dividers with minimal isolation (this is why the installation manual recommends fused leads for all hookups). The dividing circuit uses 200K over 22K resistance, mapping up to about 24 volt nominal (say 28 volts max) down to the integrated circuits intended range of 0-5 volts.

The threshold voltage for discreet values on the pump circuits is 2 volts. Although strictly speaking that is just a firmware value, so could be adjust and flashed to a new level if someone were so inclined (more info on flashing here).

There is a server side bias adjustment that can be used to fine tune the reported measurements. Resolution is certainly reliable to 10th of a volt, not much beyond that though.

Perfect. Thank you.

That also says that in your future multi-hub product ( :wink: ), the inputs could be user configured via software to be 9 analog inputs, 9 digital inputs, or any combination. Neat.

As usual, developing the user control/configuration interface side of all of that would be a HUGE task for you guys…

So in order to use the full range of the ADC my input should be approx. 24V. Using a 12V battery system only uses the bottom half of the ADC, then right?

Is the 2V digital threshold 2V out of the 0-5V ADC input range , or is it 2V out of the 12V input most of us are using (divided down 22/200)?

Yes, if you want the best resolution in you application, going out to the full 24 volts would provide that.

The 2 volt threshold is the voltage at the physical screw terminal, so 2 volts in the “real world” as measured.

Thank you for the help.

Anytime, please let us know if any other questions.

So you are assuming what full-scale voltage when you say 2V? - a 12V system?

So if I use 24V, then the logic toggles at 4V?

Sorry, not trying to be difficult.

No trouble at all, sorry if we are unclear. The system as shipped can handle up to 24 volt nominal, but the threshold in all cases is 2 volt. We just chose something high enough to be well above any spurious reading.