Recommendation for a door sensor

Hi, all.

I’m planning to make an Arduino based box to sit on the dashboard of my RV with lights to warn me about common drive-off errors. (TV Antenna or Dish up, Awning out, Storage Bay ‘X’ open, etc)

Can someone recommend to me a wireless switch for the sender side?

I need something small that, ideally, is off when closed, and wakes up to transmit only when opened. That should give me better battery life - don’t need it to be awake and transmitting “I’m closed” for days on end while the RV is in storage. Maximum range needs to be about 30’ or so. I see lots of cheap door sensors online for home security systems, but not sure if I can listen for them other than with their own control boxes.

Thanks,
Richard

Maybe you can read (and decode) the 433MHz signal from the Sonoff DW2-RF. I have just started using the WiFi version so cannot comment on battery life but it is supposed to warn when the battery is low.

Rickinnocal:
Hi, all.

I'm planning to make an Arduino based box to sit on the dashboard of my RV with lights to warn me about common drive-off errors. (TV Antenna or Dish up, Awning out, Storage Bay 'X' open, etc)

Can someone recommend to me a wireless switch for the sender side?

I need something small that, ideally, is off when closed, and wakes up to transmit only when opened. That should give me better battery life - don't need it to be awake and transmitting "I'm closed" for days on end while the RV is in storage. Maximum range needs to be about 30' or so. I see lots of cheap door sensors online for home security systems, but not sure if I can listen for them other than with their own control boxes.

Thanks,
Richard

Do I understand this correctly? You do not want the device to send continuously when the "door" is closed, but you do want it to send continuously when the door is open?
Paul

Paul_KD7HB:
Do I understand this correctly? You do not want the device to send continuously when the “door” is closed, but you do want it to send continuously when the door is open?
Paul

I intend to have the receiver box powered from the vehicle ignition, so it will be off all the time, until you turn on the ignition.
The ideal situation would be that it then attempts to pair with all the sensors. Those that are closed are actually powered down, so won’t pair. Those that are open are turned on, so they will pair and send a “I’m open!” message. On closing, they will no longer be powered, so the receiver will see them as closed.
Hmmm… Now that I write that down, I see a problem with it. If a device has a flat battery, the receiver won’t pair with it, so will assume that its closed. If the batteries flat because the doors been open / dish has been up for a while, it’s just going to give me a false sense of security.
Back to the thinking box…

Rickinnocal:
I intend to have the receiver box powered from the vehicle ignition, so it will be off all the time, until you turn on the ignition.

Back to the thinking box....

You seems to have missed my point! You don't want to waste the batteries in the door sensors when the doors are closed, but you are ok to waste the batteries when the doors are open. Is that a fair statement?
Paul

Paul_KD7HB:
You seems to have missed my point! You don't want to waste the batteries in the door sensors when the doors are closed, but you are ok to waste the batteries when the doors are open. Is that a fair statement?
Paul

The doors being open, or the Dish being up, is something that lasts at most a couple of days. The doors being closed is something that can remain constant for several weeks when the RV is in storage.

However, having the sensors 'report' their status only when the receiver is powered up and queries them would be even better. I'm trying to figure out how I could accomplish that though. The sensor obviously would need to be powered up all the time in order for the receiver to speak to it when turned on.

For a few US Dollars you could invest in a remote relay board, something like this one. They come with two Keyfob transmitters which are easily hacked using a remote switch like a SPDT magnetic reed switch. Unfortunately I have no idea how much current the Keyfob draws so it would need measured or externally powered. The receiver card just has relays do dry contacts could be used with an Arduino or similar uC. I have seen these boards as cheap as $7.00 on Banggood.

As a side note whenever I put something up for any length of time, like a winter for my bike or wife's truck I leave it on a battery tender. Small investment to prevent run down batteries.

Ron

Ron_Blain:
As a side note whenever I put something up for any length of time, like a winter for my bike or wife's truck I leave it on a battery tender. Small investment to prevent run down batteries.

I'll check into that relay board.
I have a solar battery tender for the RV batteries. I don't want to have to run wire to all the different sensors, though. With TV antenna, Dish, awnings, slideouts and bay doors there's going to be several of them.
Want to be sure I don't do this...