Sainsmart 12V, 16 Channel relay module connected to RpiZW has unwanted triggering when booting
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I’m trying to get the hydrosys4 open source irrigation control software to work with my 16 channel relay board and raspberry pi zero w.
When the pi boots up the relay is triggered multiple times, rapidly ( this is not good, the relays will have AC loads in the final setup ).
Below shows my current wiring to the 16 channel relay board. Here’s a link to a document I could find showing the relay board schematic. Sainsmart relay schematic

Is there any hardware/wiring I can add to prevent the relays from triggering during the pi boot?hardwarepower-supplypi-zero-wrelaywiringShareEditFollowClose 2Flagedited just nowtlfong013,84733 gold badges88 silver badges2222 bronze badgesasked 3 hours agoD A111 bronze badge New contributor
- i think that this question has been asked before … it has nothing to do with the relay board … search
state of GPIO pins at boot
– jsotola 3 hours ago - I have searched this issue and I can find several posts where its mentioned but then there’s the statement (It is safest to find a hardware solution if you have hardware which could be incorrectly triggered at system startup.) I’m looking for help with that hardware solution. – D A 2 hours ago
- It is unclear what is connected, why you have multiple 5V, Gnd connections. The module is unsuitable See Can you use a 5V Relay Module with the Pi? – Milliways 2 hours ago
- (1) Your link is broken. Is it this one? 16-Channel 12V [Low level trigger] Relay Module SKU: 101-70-103 US$119 – Sainsmart sainsmart.com/products/16-channel-12v-relay-module (2) Show us a photo of your wiring. – tlfong01 1 hour ago
- (3) This is the schematic of the relay linked in (1) imgur.com/gallery/M7bQp5C. (4) Please show us the photo asked in ((2). – tlfong01 58 mins ago
- (5) Imgur does not allow me to upload pictures too often. So I am uploading them as an answer. (6) Please let me know if you know how to use a multi-meter. I can show you the steps to troubleshoot. – tlfong01 33 mins ago
1 Answer
Answer
/ cont’d from comments, …
(5) Imgur does not allow me to upload pictures too often. So I am uploading them as an answer.
(6) Please let me know if you know how to use a multi-meter. I can try to show you the steps to troubleshoot.

References
(1) 16-Channel 12V [Low level trigger] Relay Module SKU: 101-70-103 US$119 – Sainsmart
Appendices
Appendix A – Sainsmart 16-ch Low Trig Relay Module Schematic

Appendix B – Ch 1 ~ 4 of Sainsmart 16-ch Low Trig Relay Module Schematic

Appendix C – Sainsmart 16 Ch Low Trig Relay Module PCB

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