Newbie Designing a 8 channel capacitive sensor system---Need schematic help

Hello Everyone,

I am building a custom reverse-trike auto and am designing a touch display system for the dashboard.
I have done a TON of Youtube video watching and understand how to program the Arduino for the capacitive touch sensors, but the thing that is kicking my butt is the schematic and wiring of the system.

Components I have:

Arduino Uno
8 channel 12 volt relays
Blank circuit boards for the project
necessary resistors

Brief description of what I am trying to do:

I am trying to make a touch screen with 8 buttons on it (capacitive sensors under a glass screen), and the touch screen will control various things on the vehicle (headlights, interior lights, etc.)

I have seen videos that show how to hook up a capacitive sensor directly from the Arduino, which I understand. And I have seen videos that show me how to connect the 8 channel 12 volt relay to the Arduino, which I understand. The thing I cannot figure out is how to connect and wire correctly so the capacitive switches control the relay switches. A simple schematic showing how it all should go together would help me. I have seen videos showing the routing on a breadboard (for one sensor), but for the life of me, my mind can't wrap itself around how to translate that to my own circuit board with 8 buttons going to the relay.

Any help would be GREATLY appreciated.

Saucytimber

wiring

SaucyTimber:
I have seen videos showing the routing on a breadboard (for one sensor), but for the life of me, my mind can't wrap itself around how to translate that to my own circuit board with 8 buttons going to the relay.

Can you post a link to one of those vids? I can help with the schematic, but I'd need to see the video first to get an idea of what you want.

Thanks for the response and willingness PowerBroker,

Here is the video that addresses how to connect the capacitive sensor to the Arduino:

And here is the video that addresses how to wire the 8 channel 12 volt relays to the Arduino:

I understand how both work individually, but I am trying to have the Arduino programmed for capacitive touch sensors that in turn control the relay switches, that will then control various 12 volt items on my car. This relay video shows a 4 channel, but my will be 8 channel.

Thanks

ST

By the way, these two videos do not show the breadboard confusion I mentioned but were simpler for me to understand, so I have been using them to try and figure out what kind of circuit board wiring I might need.

I won't be using Arduino sensors that I purchase, I'll be using copper foil under glass (like it shows in the video).

But here are the videos with the breadboard routing:

ST

Here is a picture that shows the exact 12 volt 8 channel relay I am using and connecting to the arduino. So, this picture shows everything I am trying to do except for the capacitive sensors.

Ok, attached are the pinouts for your project. No breadboarding necessary, all connections are direct to the Arduino. Using a breadboard isn’t the most reliable method for use on a motorcycle. Connections might come loose due to shock and vibe from the cycle.

RELAY.pdf (369 KB)

This is great! Thank you. I can understand all of this except for one part. On the relay diagram where you have 12 volt, would I need to have a 12 volt power supply run to each one with its own fuse or could I start at one end of the relays and chain 12 volt from one to another going down all eight?

Thanks tons.

ST

Also, my 8channel 12 volt relay pin arrangement is as follows:

GRND is the far left pin, then there are the 1-8 pins, and then a VCC on the far right (there is no actual 5v positive pin labeled)

So, does that mean that VCC is where I would connect the 5v from the Arduino?

Thanks

ST

I have started a visual diagram to help me apply the info you’ve offered (I work best from visuals, ha).
Would you mind too much taking a look at this layout I’ve started and perhaps explain the connectetions from one to the other a bit more? Your diagrams make perfect sense, but my understanding of bridging the two units are now throwing me. It seems to me that connecting the capacitors (two wires into the Arduino each) would take up most of the pin slots, which confuses me as to where the wires to the relay would come from.
Also, I have drawn this to show the bridging of 12 volt power from one channel to the next. If you could let me know whether that is okay or not, that would be good too.

Anyway, thanks for the help thus far.

ST

SaucyTimber:
On the relay diagram where you have 12 volt, would I need to have a 12 volt power supply run to each one with its own fuse or could I start at one end of the relays and chain 12 volt from one to another going down all eight?

You only need one 12V supply that feeds each of the relays. Each 12V input on the relays should have a fuse. 1 12V source, 8 relays, 8 fuses.

SaucyTimber:
I have started a visual diagram to help me apply the info you've offered (I work best from visuals, ha).

Unfortunately I'm having trouble downloading your jpg.

SaucyTimber:
Also, my 8channel 12 volt relay pin arrangement is as follows:

GRND is the far left pin, then there are the 1-8 pins, and then a VCC on the far right (there is no actual 5v positive pin labeled)

So, does that mean that VCC is where I would connect the 5v from the Arduino?

Thanks

ST

GND is Arduino GND, Vcc is Arduino 5V.

Also, the Arduino pins connected to the IN# pins on the relay modules are 0-5V digital signals from the Arduino to the relays to make each trip (or not trip) individually. Google "electromechanical relay arduino".

Here is a new pic of my understanding thus far. I feel like I am making progress, but the discussion and confirmations help solidify each step. Thanks. I hope this jpeg works for you.

ST

Hmmm, for some reason the wire lines I drew did not transfer to this jpeg file. You can imply where I've got the lines running from the arduino to the resistors and the capacitors. I'm still brain froze on how the remaining pin slots would be enough to connect to the relays. Maybe I am just not getting it......

I think this shows what I'm going for. Maybe I am just overthinking things, but the capacitive buttons in-between the whole configuration is what seems to be throwing me.

I might go mad in the process of wrapping my head around all this (I suspect it is much simpler than my brain is allowing). I have been reviewing the google material on electromechanical stuff in the meantime.

ST

looks good except for one mistake on my part.

You should connect the high side of your lights (etc) to the screw terminal in the middle, connect GND to the normally closed screw terminal and 12V to the normally open screw terminal. You then should connect the low side of your lights (etc) to GND. GND should be common to all electronics involved and can be chassis ground.

The white markings on the module tell you which terminal is normally closed or normally open.

My mistake was a BIG one. Make sure you take the advice I give in this particular post and not my previous pdf. The pdf connections will short 12V to GND lol. This would do real damage to your motorcycle, so take care that you make the connections correct!

Whoa! Good thing I am about 4 weeks from actually doing all this int the vehicle. Thanks for the update, I will be sure to make the proper changes. I am going to work for now but will post a couple thoughts with a new diagram later today when I have another spot of time to sit down and walk through this again.

Thanks

ST

Okay, so, just to be sure I have revised the original image you offered me and am offering it here for review. Please let me know if the way I have re-labeled it is now correct according to your last post.

Thanks

ST

Okay, I went ahead and did a quick revised image of the wiring thus far with your new comments regarding the relay wiring. Here is the image, please let me know if it all looks correct at this point. Also, I am still hung-up on how to wire the Arduino to the relay, is it just a matter of using the open wire from the capacitor wiring (that is, the wire without the resistor on it) and running it through to the pins on the relay so that the capacitor is “in-line” with the wire?
I think I am understanding all the rest, just that.

Thanks

ST