This is my equipment: 12V DC (10A) PSU powering Arduino Uno then 2 x Buck converters (3A) (one powers two solenoids, set at 9V, the other powers a 3.5V motor) connected to a 4-channel relay (active HIGH). One buck converter is set to 9V and is shared between two relay common points to switch two solenoids (0.1A each). The other buck converter is set to 3.5V and powers a 3.5V motor (0.12A startup, 0.6A free-run). The relay module is powered via the 5V pin and GND on the Arduino. I have a momentary switch that pulls a pin LOW and triggers relay 1 (solenoid1) to go LOW, then relay 2 (solenoid2) go HIGH, then the motor on relay 3 turns off and on until an LDR drops below a treshold) then the relays goes back to relay 1 on HIGH and the other two on LOW. There is some power supply issue I'm not understanding correctly because with it all connected, relay 1 just clicks off and on very quickly without completing the process after I press the momentary switch. When I disconnect one of the solenoids, the relay runs fine (relay 2 goes HIGH, relay 3 turns off and on). Also, when I drop the buck converter for the solenoids (relay 1 and 2 common) to < ~6.4 volts, it starts behaving correctly. I thought the switching, 5V side of the relay board is isolated from the output side that allows power to flow to the solenoids and motor. Why is the power coming from the buck converters affecting the 5V logic side of the relay module? I thought the coils were isolated from the things they are switching on/off. I've swapped the Arduino and tested the code on another 2-channel relay with the same behaviour occuring. How do the buck converters affect the 5V switching side of the circuit? The 4-channel module works fine with the USB plug connected to the Arduino (but nothing connected to the relays. How do I connect the 12V 10A PSU to the Arduino and the buck converters to get the relay module to switch correctly?
5
-
2\$\begingroup\$ Please edit your question to add paragraphs at least, it is essentially unreadable as is. Also add a schematic, much clearer than attempting to describe circuits in English. \$\endgroup\$– MatCommented Mar 25, 2021 at 10:16
-
2\$\begingroup\$ Hi! If you can show a schematic of the connections and the part numbers of the components, that would help a lot in debugging. \$\endgroup\$– Carla H.Commented Mar 25, 2021 at 10:18
-
\$\begingroup\$ OK, maybe this will help: Do I need to place the buck converters on the downside of the relays so that they're all switching 12V? That means I need one more buck converter to power the solenoids separately. \$\endgroup\$– Jason AxfordCommented Mar 25, 2021 at 10:18
-
\$\begingroup\$ @CarlaH. Thanks for replying. Sorry, I didn't see your comment before commenting myself. I'll work on that and get back to you. \$\endgroup\$– Jason AxfordCommented Mar 25, 2021 at 10:20
-
\$\begingroup\$ My brain just melted trying to decipher the monolithic block of text. Firstly, take the Arduino out of the equation. operate the relays by connecting the input wires to 5V selectively to simulate the operation of the Arduino. Does that work? How have your wired everything? Wires have resistnace, so if the high currents aren't flowing down the right wires, they might upset the Arduino. Layout and wire size is critical.Even having a simple chicken scratching of the basic layout that reflects how things are actually wired will help. \$\endgroup\$– KartmanCommented Mar 25, 2021 at 12:04
Add a comment
|