Seeed Studio i2c Motor Driver

1

TLDR; Do you sell seeedstudio’s Grove - I2C Motor Driver (TB6612FNG) ? I see you have two older models which use the less efficient L298N chip.
I am particularly attracted to its Grove i2c interface, and it is already supported by ESPHome and Home Assistant.

Background

I have located a Latching Solenoid Valve to use in my greenhouse, with specifications including:

image
image328×314 24.2 KB

  • Working voltage: DC 4.5V
  • Working mode: positive pulse open valve, negative pulse off
  • Pulse width: 30ms

By latching at the solenoid valve it will use a lot less battery power … but I’m not sure how to connect to ESP32 and provide +ve and -ve pulses.

I have looked into generating -ve voltage, which led to the DPDT relay rabbit-hole, and from there to H-bridge.

I’m not into electronics (and at 66 my goal is not to become a professional electronics engineer) and I don’t trust my soldering - so an off-the-shelf module would be preferable. Over in the Home Assistant ESPHome forum someone suggested the “TB6612FNG could be good choice here”, and I found that seeedstudio have one with a Grove interface and ESPHome driver … which I assume means there will be no need for flyback diodes or other electrical wizardry :wink:

I checked Core’s website and discovered you stock Seeed Studio’s Grove - I2C Motor Driver (SS105020001) and Grove - I2C Motor Driver (SS105020093) - but not the TB6612FNG version. I have come across the comment that the FB6612FNG is “More efficient than the L298N with no significant voltage drop”, and it appears to be newer than L298N chip … so wondering if there was any issue with it that prevents Core from selling it ?

Is there another product you would recommend ?

2

Hi Donald
You are right. It is a bit difficult to get a negative pulse with a single power supply.
You need to generate a suitable positive pulse and have the means to invert or reverse it.

There are more ways to reverse a signal than using an H bridge which sometimes can get a bit messy. One pretty clean way is to use a DPDT relay. The size depends on what sort of current the valve needs.
If the current is quite small there are relays with an IC type DIP16 or similar form.
Suggested circuit attached.

image
image537×613 5.72 KB

The relay pin numbers relate to an LY style device. The actual numbers will depend on the type used

Be aware that a lot of this style relays have the flywheel diode included in the package and thus becomes voltage conscious

In operation you would probably set the relay for the desired direction then generate the operating pulse. Pretty clean and simple.
Cheers Bob

Hi Pix
This escaped my attention but you will need a flywheel diode across the valve solenoid coil. As the voltage applied to this coil changes direction the only place to put it will be between relay pins 11 & 21 with cathode at pin 11