Open closed sensor with wireless indicator

Thread Starter

Militarymedic23

Joined Aug 14, 2022
8
Hello,
I’ve searched around for this general idea for quite a while and no one seems to have any actual products that meet the description.
My idea is a very simple, hopefully, open and close sensor that would go into the bed of a pick up truck tailgate. And a simple LED wirelessly connected indicator to show when it is open.
Maybe my idea of simple isn’t quite right for this, but that’s how it’s running through my mind.
Looking to see if anyone could advise on how difficult this type of project would be to actually build yourself.
 

Irving

Joined Jan 30, 2016
2,993
Why wireless? Adds a layer of complexity and unreliability you don't need.

Simple door push switch wired back to an LED on the dash, similar to interior light switch wiring is all you need. Anything else is overkill.
 

Irving

Joined Jan 30, 2016
2,993
Understood, but automotive is a noisy harsh unforgiving environment - the reliability of a battery-powered wireless device won't be great - standard hobby parts just aren't up to the job. You only need to run one wire if the pickup bed is properly bonded to the chassis as it should be for the rear light clusters (or there'll already be a common return wire), plus you have an obvious route to follow. The reason you haven't found something off the shelf is that they just aren't cost effective to meet reliability requirements compared to a few feet of wire.
 

MrChips

Joined Oct 2, 2009
26,791
I agree with @Irving.
To go wireless would require power at the sensor.
In any case you would want two LEDs in the cab, one to show open and one to show closed.
 

Thread Starter

Militarymedic23

Joined Aug 14, 2022
8
Points understood, thank you.
I suppose without knowing the exact details on components, there are probably options out there but like you were saying they’re probably far from cost effective in actually try to build something.
i’m tracking with having a common ground in the bed/chassis, but can you give a bit more of an example on what the wiring would be from the sensor to a double LED indicator?
I can spell things out 100 ways but until I see a picture I’m kind of lacking and being able to visualize it in my mind.
 

Ya’akov

Joined Jan 27, 2019
6,275
Welcome to AAC.

The automotive environment is very noisy and difficult but there are wireless backup cameras that use Bluetooth to send video so it's possible you could use Bluetooth to do it.

It would not be an easy project, but it certainly seems in the realm of doable.
 

Reloadron

Joined Jan 15, 2015
6,827
Think about for example dome light wiring. Along these lines.

LED GNS Switch.png

SW 4 is a Normally Open switch tied on one side to chassis ground and the other end a single wire to wherever you want your LED(S). The example reflects two LEDs. Actually you can buy LEDs for automotive use which include the current limiting resistor. The switch can be normally open or normally closed depending on when you want the LED(s) lit with gate open or closed.

Yes, there are wireless modules which can be used but the wireless module will need a power source. A single wire along the lines of a simple dome light should do just fine and is simple. Going wireless will just require a little more work actually.

Ron
 

Thread Starter

Militarymedic23

Joined Aug 14, 2022
8
Think I’m tracking.
And if I want to reduce this down to an even simpler design, with just one LED light there would be one less wire to worry about.
but if I wanted an LED light up near let’s say the rearview mirror, I was still need to get 12v up to that and then another wire running out to the bed of the truck to complete the circuit right?
If so, I think there are one or two options I know of in the passenger side fuse box that would provide 12 V. And I can’t imagine an LED light and a simple sensor would take hardly any power draw.
Next question, what are the preferred sites to get supplies like this? I have seen a few things that I have bought various parts from before that or somewhere in this realm but digikey and Amazon tend be the common ones I’ve seen. But I know the LED supply is good for getting individual diode‘s.
 

Reloadron

Joined Jan 15, 2015
6,827
but if I wanted an LED light up near let’s say the rearview mirror, I was still need to get 12v up to that and then another wire running out to the bed of the truck to complete the circuit right?
Yep, that would be correct.

LEDs have a small power draw. Typically 0.020 amps or less for basic indicator types like this one and commonly sold i automotive parts stores. All you need is a switch and LED. Typical automotive voltage is about 12.6 volts to 13.6 volts or greater when running.

Ron
 

Irving

Joined Jan 30, 2016
2,993
Generally indicators like 'door open' are off when the door is closed and on when it is open. The brain is better at reckonising that 'light on' = problem. I would consider using the existing door switch circuit and tapping into that. Then you get the benefit of any existing audio warning as well as visual and no additional cab wiring needed.

Do you have a schematic/wiring diagram for the vehicle?
 

MrChips

Joined Oct 2, 2009
26,791
I would use a SPDT switch that connects to chassis ground on either open or close.

If you want to simplify it with a single indicator, then the SPST switch is closed when the door is open, or just use one side of the SPDT switch.
 

Irving

Joined Jan 30, 2016
2,993
I would use a SPDT switch that connects to chassis ground on either open or close.

If you want to simplify it with a single indicator, then the SPST switch is closed when the door is open, or just use one side of the SPDT switch.
Standard automotive fit courtesy-light door switches are push to open (NC) sprung plunger with a moving contact to a ground barrel. They are cheap, very reliable, virtually impervious to contaminants and essentially maintenance free.
 

MrChips

Joined Oct 2, 2009
26,791
Standard automotive fit courtesy-light door switches are push to open (NC) sprung plunger with a moving contact to a ground barrel. They are cheap, very reliable, virtually impervious to contaminants and essentially maintenance free.
Yes, I am aware of that.
But if you choose a SPDT switch you can wire it any way you desire including separate lamps for open and close. A heavy duty roller switch comes to mind.

1660596427421.jpeg
 

eetech00

Joined Jun 8, 2013
3,313
Think I’m tracking.
And if I want to reduce this down to an even simpler design, with just one LED light there would be one less wire to worry about.
but if I wanted an LED light up near let’s say the rearview mirror, I was still need to get 12v up to that and then another wire running out to the bed of the truck to complete the circuit right?
If so, I think there are one or two options I know of in the passenger side fuse box that would provide 12 V. And I can’t imagine an LED light and a simple sensor would take hardly any power draw.
Next question, what are the preferred sites to get supplies like this? I have seen a few things that I have bought various parts from before that or somewhere in this realm but digikey and Amazon tend be the common ones I’ve seen. But I know the LED supply is good for getting individual diode‘s.
How about using a wireless door monitor switch and your phone?
 

ThePanMan

Joined Mar 13, 2020
473
My idea is a very simple, hopefully, open and close sensor that would go into the bed of a pick up truck tailgate. And a simple LED wirelessly connected indicator to show when it is open.
You don't know if your tailgate is open or closed just by looking out the back window?
example on what the wiring would be from the sensor to a double LED indicator?
If you go that route you'd have to wire to a switched power source otherwise there's a potential for running your battery dead.
I had thought about something like Bluetooth, but to me that is very overkill.
"Overkill"?

The best route is a simple grounding switch like the door switches already on your truck or wife's car (assuming you're married and your wife drives a car). Power from the battery goes to the LED through a switched source so you don't run your battery down. From the LED it goes to the tailgate where it is grounded. When the door is in the open position (assumed you'd prefer to know that as opposed to being closed) the LED comes on, just like the dome light comes on when you open the door.

Just make sure you fully understand how to wire up an LED. It would seem straight forward to the most inexperienced person, but there are other matters that need to be considered. If you start with a 12 volt LED then most of the calculations are already done for you. Likely you won't have to do any more calculating than to just wire it up in the correct polarity.
 

ThePanMan

Joined Mar 13, 2020
473
If you want to have both OPEN and CLOSED indicators then there's no off the shelf parts you can use. You will have to do the math and get two LED's, one that is lit when the ground circuit is open and one when the ground circuit is closed. Open and Closed in electrical terms are not synonymous with the tailgate being open or closed. An open circuit means one that does not conduct current. A closed circuit is an active circuit with electrical current going through it.

I'll give it some thought about how to use two LED's, but I'm busy with other stuff. Spring cleaning near the end of summer. Go figure.
 

ThePanMan

Joined Mar 13, 2020
473
One final thought before I get back to sorting China dishes: At night I hate extra lights glaring at me while I drive. I'd only opt for the "OPEN" indication.
 

Thread Starter

Militarymedic23

Joined Aug 14, 2022
8
A lot of good input, thank you very much. I think just keeping it to a simple LED on sensor open is about all I want to accomplish. In a possible leap of faith it would be nice to possibly have it also activate some strip lights in the bed of the truck. I didn’t get the fancy model so there is no bed lighting.
I have done quite a bit of 12 V wiring in vehicles, so I am no stranger to that type of work. And I also have a timed power supply coming from the battery to inside the cab. Just didn't know how to connect the dots for the various components that I would be looking for.
 
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