New here and I’ve spent the night researching pages and pages of this topic to help with me project, but I haven’t found a straight answer…at least for my limited cranial skills.
I’m basically a noob when it comes to electronics, so don’t assume I know anything. I’m looking for some help to safely connect up some hardware I recently purchased.
Project Context: we have some custom hardware, harnesses designed for a 4 lane slot car track. I’ve wired 4 tracks before with a basic power relay to cut all track power, but this project is much more advanced.
Project Details: We have a harness coming off our Arduino board that needs to be connected specifically to a 4 relay board (in the attached picture). The relay board will be controlled by an Arduino board via a race management software (RMS) system on our computer that will cut (individual lane) power to the track when a car runs out out of “fuel”. Side note for more context, a full fuel tank is set to a certain number of laps - or less, if lap times are below a certain user defined threshold.
FYI - I have picture attached of what I’m going to outline - it does contains an error, on the terminal side where it says “closed”, it should state “common”.
We are using an Arduino board which is connected to (and powered by) our computer via USB cable. The Arduino board has 4 pairs of pigtails already connected to it, that correspond to certain lane numbers. We’ve tested each pigtail with a multi-meter noting that it puts out a 5v charge when the RMS triggers it (i.e., a signal to cut power). So that appears to address powering the relay board.
We have been instructed to connect each pigtail into IN1 (for lane 1), IN2 (for lane 2) and so forth. With the associated ground for each pigtail to be connected to the GND.
We are assuming we need/should jump the 4 grounds together and connect to GND - please advise if that’s not appropriate.
On the terminal side of the relay board, we want to use the normally closed (NC) spots - as we want the track power circuit on when racing, until triggered - ie., a signal from the RMS via the Arduino cut to track lane power.
So I assume that a specific track lane positive wire connects to the corresponding NC with a specific track lane’s negative wire connected to the common. Let me know if that’s appropriate.
Hopefully, I’m on the right track. Where I really am at a loss is how to then connect up the track power supply to the relay board.
Our power supply is rated at 10A, 5-20 VDC. The track voltage will most likely be running between 9-10 DC volts for some context.
First question about the power supply, the board should be able to handle that ongoing 9-10 (DC) volts based on its specs to handle up to 30 VDC, I assume I’m correct here, right?
Second question, I need to connect both the positive and negative posts off the power supply to the relay board.
From what I’ve read and researched, I’ve read various articles that have conflicting statements. I read here: http://yourduino.com/sunshop2/index.php?l=product_detail&p=201
…that I should connect the positive from the power supply to JD-VCC and power supply negative to board GND. Confirming that in this post (http://forum.arduino.cc/index.php?topic=157144.0) I read “If you remove the jumper and wire an external +5vdc to the JDVcc pin and a ground pin somewhere then the relays will get there coil voltage from your external +5vdc voltage source.” I assume the GND on the board…
In other articles and forum posts (eg., http://forum.arduino.cc/index.php?topic=131224.0) I’ve read that power supply negative goes to the GND with the positive going to VCC. Another post (http://forum.arduino.cc/index.php?topic=102978.0) I read said negative to VCC with positive to JD-VCC…but I believe that’s if the board was taking power from the Arduino which I’m not planning…I think.
Which is why I’m here…dazed and confused - and wishing the fellow who made and sold me the custom gear would help guide me safely connect up. He won’t because he doesn’t want to be sued…which begs the question why he builds this stuff commercially…but that’s a rant for another time.
I feel like I’m so close on this, but it’s killing me but I don’t want to experiment and damage the gear.
So please have a look at my crude picture, as you’ll see everything I said above as well as my first assumption around wiring the power supply positive to VCC.
Many thanks in advance for any help!
Tom in Canada, eh