Just got my first Raspberry Pi, as a Software Engineer, I’m disappointed that it’s taken me this long. I’m on the Home Assistant (HA) band wagon and keen to setup my first project.
So, as a complete newbie, what is the best setup to detect mail has been entered into the letterbox?
I’m assuming either a vibration sensor or a lever that is flicked when mail goes in? The letterbox is a fair distance away from power so I would prefer not to wire it, plus it will be ugly to have a wire going into the letterbox - so battery powered would be preferred.
Obviously, I need to be able to use the solution with HA.
Pity, if it was a flap you could arrange a microswitch or similar to operate when the flap opened. Having a slot means you have to detect different size envelopes and a switch probably would not activate with say only one envelope. There are sensitive microswitches available but not very common.
The easiest I can think of might be something like a through beam detector sited across the letter box arranged to activate when the beam is broken. Then a micro something to process this and send by some sort of radio comms to a receiving system to alert you in some way.
I am pretty sure there have been similar (not necessarily letter boxes) projects on this forum that you could squeeze for info or one of the Core support group may remember something similar.
Just in case a single envelope could be missed by not completely breaking the beam maybe the detector system arranged top to bottom would be better. That way there is a good chance any article would cover and completely block the beam
A Pi is overkill for the letter detector, although it would be a very good basis for the HA.
The littlest ESP is quite capable of detecting a letter and sending a message to the local LAN over WiFi, and it consumes much less power than a Pi.
There are a number of other ESP modules, any of which could do the job.
The detector could be a IR receiver/transmitter mounted at the back of the letterbox looking at a mirror glued to the rear of the front panel. That way anything falling from the slot will break the beam, while the module can be protected from the weather. You could build the whole assembly on a small frame that slides in from the front. You would have to ensure the antenna is not shielded by the letter box.
Apologies for the misdirection. I will be running HA on the Raspberry Pi only, and have everything else in the house running separately.
I’m hoping to build a little device that will run using a Break Beam Sensor like you’ve shown above, and interact over Wifi preferably. Built on an Arduino or something small and low powered, I’m hoping you can get 9V battery solutions.
I would not bank on that. A 9V battery will provide a little bit of current (multimeter, smoke detector etc) for quite long time. But increase the current a bit and the time will drop dramatically. I think I would expect the end solution to be a rechargeable LiPo or similar.
I think Jeff’s suggestion of a transceiver and mirror is better that mine with far less chance of missing anything put through the slot.
PS Also simplifies wiring as there is only one physical point involved.
A standard Arduino won’t do WiFi without an addon, and the combination (or any enhanced Arduino with WiFi built-in) is very power hungry. An ESP, especially a little one, is going to last much longer on its battery.