What is it? Three half H-bridge and a common half H-bridge that can be used to discharge a (9V/12V/24V) capacitively stored charge into one of three selected latching Solenoid coil. A current limit...Read More…
Three half H-bridge and a common half H-bridge that can be used to discharge a (9V/12V/24V) capacitively stored charge into one of three selected latching Solenoid coil. A current limited (300mA pk) boost converter (MC34063A) is on board to build up the stored charge from a low voltage (5V) supply.
To drive latching type irrigation solenoids with an RPUno.
The boost converter draws 300mA max, which leaves 200mA for other devices from a 500mA USB supply.
Latching solenoids are driven with a current pulse that last a short duration. The pulse flows in a coil and establishes a magnetic field. Since the pulse is a short duration the wire size to the coil can be significantly reduced, but some testing may be needed. One of the valves I use has a coil that measures about 4.7 Ohm with a DMM. I am able to drive it with 10 meters of CAT5 pair (24AWG) which has 1.7 Ohm. The peak current flow is over 3.5A for a very short time, so the wire does not get hot. I recommend that the peak current is less than about 5A otherwise the p-channel MOSFET safe operating time is too short to be robust.
|Shipping Rate||First item||Additional items|
United States Postal Service: Priority Mail
Priority Mail Small Flat Rate Box will hold two RPUno, or two shields (RPUftdi or RPUadpt) and an RPUno.
We recognize our top users by making them a Tindarian. Tindarians have access to secret & unreleased features.
We look for the most active & best members of the Tindie community, and invite them to join. There isn't a selection process or form to fill out. The only way to become a Tindarian is by being a nice & active member of the Tindie community!
I am working on what may be thought of as a SCADA system for the garden and workshop. I prefer WiFi to be on the SBC (Pi Zero) or host computer that I can then connect to a multi-drop serial for interfacing the somewhat industrialized microcontrollers. To bootload, I have set up the multi-drop serial so it has a full duplex connection between the host and microcontroller and a half-duplex connection that can manage what is (or is not) connected to the full-duplex bus. This is done with a specific favor (Intersil) of RS-485 transceivers.