Analog I/O building blocks

I’d like to see an application for a mobile device (i.e. a phone) that used building blocks behind the application interface to allow a user to control sensors and actuators remotely.

For example, a temperature controller would consist of three blocks:

An analog input, which would allow selection of the device from a list on the network, the type of device (thermistor, RTD, T/C, etc.)

A block for a control methodology (bang bang with deadband, PID, etc).

A block for the control actuator (On/Off, PWN, AO, etc).

By building with these basic blocks, one could achieve and quick and easy functionality for folks not that aware of control systems. Of course MIMO blocks would also be needed to perform some basic math functions on signal inputs or logical operators (if the vent is closed, turn it on before starting the cooling fan).

I see this as something akin to LabView for the common folk, but without the complexity inherent in LabView’s dataflow diagrams.

Great Idea, @RoughOne, and I think that it’s very close to what we call an Eventor Widget

These Eventor widgets can do PID control to a setpoint?

@RoughOne
Could you please explain how do you envision it in more details?

I am not familiar with “Eventor widgets” so I have no idea how they would work.

Imagine IFTTT … But for widgets on your dashboard in Blynk. An interface to build a rule which triggers event - here it is.

PID is a way to control the RATE at which my greenhouse fan turns to bring the temperature under control. Most consumer devices are ON/OFF and as a result have bang bang (on off) controls. Some applications however, it would be ideal to be able to the rate of change of the process, particularly while trying to maintain a setpoint, such as temperature, not to mention WHILE maintaining something such as a minimum airflow or humidity different from ambient outside humidity.

If you are just looking to a consumer market, bang bang works, because nearly all of the things one would control in a consumer market ARE On Off widgets. The sellers feel those sell better, so that is what they make. That in turn creates an inherent limit on controllability. That said, you can operate many things at less than rated voltage to introduce variability. Light dimmers are a perfect example. People did not always want the harsh glare of lamps, but they did not want darkness either, so someone invented a dimmer switch. Now a dimmer outlet, attached to a fan. So a ‘rule’ would be, use this fan at a varying speed to control the temperature of this greenhouse to x degrees, while maintaining airspeed at least at y to promote evaporation. If needed, you can open the vents z, to do so, but don’t let humidity get above 75%. So PI controller for the fan so it does not wander off to full speed or zero with integrator wind up error and an if then for the vents if temp exceeds x for some indeterminate amount of time, determined by the PID (approaching an uncontrollable solution). I hate to ask this, but does that make more sense?

1 Like

Of course all of that changes abruptly with the day/night cycle as well. No fan and vent when outside temperature is above the dew point might be a good rule for that time of day.

Yes, I was close to understand it almost the same way. Thanks for explanation and examples - they usually work best.

I think that building such logic would be easier in code, but I also like the node-based flows. The only problem with them is that they become very complicated fast. But in your example, measuring the range and giving ranged output seems to be doable. I’ll consider it when making UI for it. If you send me any references that you like - I would appreciate this.

Take a peek at a program called LabVIEW. It is insanely priced these days, but has some excellent concepts for rapidly developing systems for control which do not involve much coding in the traditional sense. We used it at NASA for environmental control systems, imaging systems, motion control, medical systems and more. Something akin to that for the ordinary user would be an amazing addition to this new internet.

1 Like

@RoughOne
Just came across http://nodered.org/ - what do you think about it?

2 Likes

Here is another node program. There is a lite version and I believe if you like it, the full version is $50. I think it would do what RoughOne is looking for

sorry I forgot to paste the link in my last reply

http://www.embrio.io/