Product search - sending 5V TTL signal

Hi, I’m trying to find the right NCD device for my application. I’m trying to control the following valve driver:
The valves can be switched either by using a SPDT relay or 5V TTL signal. I think the 5V TTL would be easier to implement. The valve is turned on when the input pin is taken high (+5VDC) and turned off when the input pin is held low (grounded). The pins should always be held low (when the valves are turned off) and not left open circuit. Do you have a device that can do this? I need to control 7 valves, so the NCD device should ideally have a minimum of 7 or 8 channels. The NCD device will be connected to a Raspberry Pi. I’m not that familiar with electronics. Any help would be greatly appreciated. Thanks!

Are you familiar with I2C communications on the Pi by any chance? If so, we have a solution that could help you.

I’ve used I2C devices before, like the 0-10V I2C DAC device. I just used the code that you guys provided for that device.

This board is really popular for GPIO:

A I2C Interface will make connection much easier:

Please let me know if you have more questions.

Thanks Ryan, is there any difference between that board and this one?

Also, should I set the pins as digital input or output? And do I need to enable the pull-up on the pins?


There is no difference other than a smaller profile. Programming is the same and at a lower cost (I actually forgot about that one!).
You will want to set the GPIO to Output.
You do NOT need to enable the pull-ups, this is for GPIO Input applications.
Once the GPIO is set to Output, you will need to set the GPIO lines high or low.
Hope this helps.

Got it, thanks for clarifying. We’ll buy the board and test it out. : )