I live in an area in The Netherlands called Zaan district. It got its name from a small river called the Zaan (https://en.wikipedia.org/wiki/Zaan) In the 17th century this area was considered the first industrialized area in the world. At that time there were over 600 windmills active. A lot of windmills have disappeared over the years because of fires, storms, etc. but some are still active and can be visited as well. (https://en.wikipedia.org/wiki/Zaanse_Schans)
Also, some of the characteristic wooden houses from the 17th and 18th century still exist. My house is built around 1750 and it is a national heritage site. On the pictures below: on the left is my house now, and the black/white picture is made in 1897.
So why am I telling you all this?
During this part of the year, starting from Black Friday until Christmas, people will be shopping a lot. This year is different, for the obvious reason. A large part of the shopping will be done online. As most people work from home it can be very convenient as well to order online, as you will always be home when the packages are being delivered.
So if you order your gifts in time, everything will be ok. But what if you don’t hear the doorbell at the place in the house where you work?
An option is to work in a room where you can hear the doorbell or you can let the delivery person know that the package can be placed somewhere outside. In most cases, in our climate (RAIN!) that is not an option.
I also thought of getting a doorbell with a camera, so I can see the delivery person. But because of different reasons, I cannot use that:
- Public space is seen on the camera, which is not allowed. And probably GDPR issues.
- As mentioned in the introduction, I live in a monumental house from the 18th century so it would look a bit strange.
So, then I was thinking to build something where I could use my existing doorbell and get notified in my location where I work. This doorbell is also old, as you can see in the picture.
It’s mechanical and works like this: Someone at the door rings the bell (literally: pulls a handle), this handle goes through the wall into the house, inside the house a wire is attached from the handle to a spring where the bell is connected too.
During my brainstorm to come to a solution for this I was thinking in different directions:
- do something with the sound of the bell.
- do something with the movement of the bell.
I also took into account the components I already have, as delivery is the problem 😁.
I came up with the following:
A sensor that detects the movement of the bell, which sends a signal to another device to let me know if someone is at the door.
Therefore, I used a tilt sensor connected to a Wemos D1¹ microcontroller which sends the signal via MQTT² to a Raspberry Pi³, with some LED’s connected that light up when the tilt-sensor detects movement.
The hardware was relatively easy to set-up and also programming was not that hard. I found some useful examples which I combined and changed a bit for the Wemos. For the Raspberry Pi, I used a Sense-hat. This hat has LEDs that can light up. The programming was done in Node-RED⁴.
I connected this hardware to the doorbell and a few alterations later it worked pretty well.
But you know the feeling: if you order something you get excited, you want to receive this as soon as possible. So, every time the doorbell rang, I ran down the stairs and to the front door, but often there was someone else at the door, my children (who have a key, but it is easier for them that I come to the door) or someone I don’t want to open the door for…
I want to solve this and I was thinking to use a camera. Stick this on the inside of the door on the window. That camera can be connected to another Raspberry Pi.
It can work like this: when the doorbell rings, the tilt sensor is activated, a signal will be send to this Raspberry Pi and a picture is taken and send to the Raspberry Pi in my home office. On a display is shown who is at the door.
But the issue of taking pictures of the public space, as I wrote at the beginning of this blog, is back. So the next step is to think about a solution for this issue. Maybe something is possible with the angle of the camera, or automatically blur the background on the picture, etc.
Maybe you as a reader have a nice solution for this challenge. Let me know in the comments!
¹ Wemos D1: mini WiFi microcontroller (development) board. (https://www.wemos.cc).
² MQTT: MQTT is a standard messaging protocol. It is designed as an extremely lightweight publish/subscribe messaging transport that is ideal for connecting remote devices with a small code footprint and minimal network bandwidth. (https://mqtt.org).
³ Raspberry Pi: a low cost, credit-card sized computer. (https://raspberrypi.org).
⁴ Node-RED: a programming tool for wiring together hardware devices, APIs, and online services in new and interesting ways. It provides a browser-based editor that makes it easy to wire together flows using the wide range of nodes in the palette that can be deployed to its runtime in a single click. (https://node-red.org).
