A wave of flu hit my hometown. And I wasn't spared. So my drink of choice for about three weeks was tea. I remembered how I saw a video, years ago, where someone used an Arduino Uno and a servo to dip a teabag into a cup. Well, it shouldn't be so hard to make a similar project with an ESP8266, should it?
Materials
Well, since I felt too sick to go outside, I took, what I've found in the basement. I still got some SG90 servos. And for the stand I used some angle brackets, which I fixed with some zip ties. As an arm for the servo, I found some plastic tongue depressors.
Setup
Quite simple. You can use the same 5V input for powering the servo and the NodeMcu. All you need is to select a digital pin for the servo. Any pin will do, since every digital pin on the NodeMcu has PWM capability.
Video
Maker Faire
The IoT TeaMaker was first featured at the Maker Faire Ruhr 2019 in Dortmund, Germany. Everyone could see the TeaMaker in action and try it for themselves.
There are different bio metric sensors on the market. They are commonly used to access a private area. Let it be a door, a safe or the privacy of your smartphone. The most known is the fingerprint sensor. A commercial bio metric sensor costs quite a fortune. But there is a cheap alternative for the Maker community. A fingerprint sensor for around 20€.
But how to save and identify a fingerprint with an Arduino? Well, you don't need to. The sensor does all the work. You only have to tell the sensor what to do.
Wiring
If you're lucky, you'll get a color coded connection cable. If you aren't, you will get one where at least the GND line is marked. It should be in one of the corners of the cable. From there you can find the rest. The order would be: GND - RX - TX - 5V. And two pins without a connection.
You have to connect GND to GND, VCC to 5V, TX to RX and RX to TX. But if you want to use the serial monitor to watch your results, you shouldn't use the Rx and Tx on the Arduino side, because it will conflict with the USB-port. You can use the Software Serial library and use pin 2 and 3.
The sensor, I received, was only 5V compatible. So if you want to use it with a NodeMcu or any other ESP, you have to add +5V to power the sensor.
Programming
There is no need to reinvent the wheel. If you search for "fingerprint" in the library manager of your Arduino IDE, you'll probably find two libraries. I used the one from Adafruit. It's equipped with examples for a quick start.
With the example sketch "enroll", you can start saving fingerprints to the sensor.
To test it, use the sketch "fingerprint". You'll get the found ID in the internal database of the sensor and the probability for a positive match. With that, you have all you'll need to build your own access control.
I always wanted one of those fancy LED stripes that you can control with your mobile or tablet. Should be easy to install, lightweight and customiseable.
Well, my brother-in-law is fascinated of this topic as I am. And Christmas was at our doorstep. So what better to do than try to build him a DIY-light.
Well getting started with it was quite frustrating. And it took me quite a while to figure out how it is done since this was my fist contact with the ESP8266.
After I posted a video of the result on FB, I was getting many requests for a manual to this.
Shopping List
Before soldering it to a PCB, I prototyped it on a breadboard. Here is everything you'll need.
The level shifter might not be necessary. The NeoPixel stripe could also work with 3.3 V on the command line. But it would be best if the difference between supply voltage and command voltage would not be so high.
And be aware not to power a whole NeoPixel stripe from your controller. On other Projects I blew up two Arduino Nano.
