MiniZed Sainsmart relay connection

I am driving a Sainsmart 4 Relay Module from MiniZed.

Because it needs 5 volts, I connected JD-VCC to 5v on Arduino Shield of MiniZed.

VCC is connected to 3.3v VCC of MiniZed.

Ground is connected to ground.

IN4 of Sainsmart is connected to an output of MiniZed.

The relay allows a connected module to have its VCC connected/disconnected on K4 of Sainsmart.

All seems to be working well, but I am wondering if 5v of relay could draw too much power. I did not see any specs for 5v on the MiniZed HW users guide.

An alternative would be using an external 5v power supply (breadboard power supply), but so far, the setup appears to work.

I plan on doing some testing of the setup, and I would not want to jeopardize my MiniZed.

Regards,

Todd Anderson

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0 ctammann over 3 years ago

Hey Todd,

Could you provide a simple diagram of what you are talking about? I think I follow but I don't want to make any assumptions. 5V on MiniZed through the Arduino is passed straight from Vin through a 0 ohm (0603) resistor. Your current capacity is theoretically limited by the current rating of that resistor, which is the lowest rated in the path. Double check the current draw on your relays and make sure it doesn't exceed the rating for a 0 ohm 0603, for reference Vishay says about 1.5A max - https://www.vishay.com/docs/31017/rcwp99.pdf

R83 should be the limiting device
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0 tanderson over 3 years ago in reply to ctammann

This is what I ended up doing - I needed 5 volts for the JD-VCC, and I was not able to consistently bring it from MiniZed, so I used a separate power supply. SEL1 is used as IN4 input to control the normally open connections. Vcc is 3.3 volts. There is common ground.
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0 tanderson over 3 years ago in reply to ctammann

This is what I ended up doing - I needed 5 volts for the JD-VCC, and I was not able to consistently bring it from MiniZed, so I used a separate power supply. SEL1 is used as IN4 input to control the normally open connections. Vcc is 3.3 volts. There is common ground.
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0 tanderson over 3 years ago in reply to tanderson

FWIW, I swapped out the Relay 4 Board for a single-relay board that runs on 3.3 volts. I did not require an external power supply, MiniZed Vcc worked just fine.
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