Is flowIO intended to work where valves open, then pumps turn on? Or can we run pumps prior to valve opening to create a back pressure?

The use case you suggest is similar to what another person is also interested in. Where rather than pumps, they wish to use a finite amount of compressed air instead. Thus I am now thinking of developing a whole new type of module for FlowIO, a compressed-air module, that can be swapped with the pump modules if the user wishes to use that instead of pumps. Would that be something of interest to you and your colleagues as well? If so we can have a brainstorming session where we discuss what would the suitable design specs be.

Hi Kyle, these are great questions and the short answer to both of them is yes. Here are the full answers:

Can we run pumps prior to valve opening to create a back pressure?

If we consider the software stack of FlowIO, https://www.softrobotics.io/software-stack the lowest layer (pneumatic driver) gives you the ability to control individual pneumatic components. In this layer, you have the complete freedom to decide which valve and which pump to turn on / off and in what sequence. This layer contains the following functions, that you can invoke from the Arduino API:

Thus, for instance, if you choose to first (1) start the inflation pump, then (2) open the inlet valve after some delay, and finally (3) open one or more of the port valves you can do this in the Arduino IDE as follows:

flowio.startPump(1);
delay(50); //assuming you want to have some delay
flowio.openInletValve();
flowio.openPorts(0b00000011); // this will open ports 1 and 2

Is FlowIO intended to work where valves open, then pumps turn on?

The higher layers of the software stack are mostly just abstractions of the driver layer. Lets, for example, see how the startInflation() function of the API is implemented internally in the FlowIO library.

Function Description:

Function Implementation:

void FlowIO::startInflation(uint8_t ports, uint8_t pwmValue){
    stopAction(ports);
    if(_config == GENERAL || _config == INFLATION_PARALLEL || _config == INFLATION_SERIES){
        if(ports<<3 != 0){
            openInletValve();
            setPorts(ports);
            startPump(1, pwmValue);
            if(_config != GENERAL) startPump(2, pwmValue);
        }
    }
}

We see here that the internal sequence of events is as follows:

1. Stop any ongoing action

2. Check if the current pneumatic configuration supports inflation.

3. Check if all the ports are now closed

4. Open the inlet valve

5. Open the port valves on which inflation is desired

6. Start the inflation pump at the PWM value specified in the argument.

7. If the configuration is Series OR Parallel inflation, also start the second pump.