already little sun helps…

The following images show that already little sun as today helps to recharge the LiPo accu of the solar-powered AM2315 sensor.

As you can see, for mid of May it is a little bit cold. After noon, the clouds thinned slightly and the temperature grows up. The IP camera image shows the cloudy sky.

But, the prognosis for the afternoon is not so bad. Look at the evening what happened.



already little sun helps…


AM2315The AM2315 is a temperature & humidity sensor with an I2C-interface in a nice enclosed style. The sensor contains a DS18B20 temperature sensor and a capacitive humidity sensor. A microcontroller inside builds the sensor interface and works as an I2C-slave.

For outside measurements it is also advantageous that the AM2315 comes in a rugged case with mounting bracket. While it is not rated as ‘weatherproof’, it is more suitable than SHT PCB-breakout sensors for measuring outside.

After crimping a Grove-connector we can connect this sensor to a Grove Arduino sheld hooked on a Wemos D1 board, for example. Or you connect the wires to a Wemos D1 mini.


At Github you will find an AM2315 Lua module and it is easy to integrate the AM2315 into your own application. I have included the AM2315 sensor into my DHT11 network and it sends now outside data to the MQTT. Its ID is ESP8266-13972685.

The data coming from the AM2315 sensor are marked red in the screenshot while the data of another outside sensor ASH2200 are marked orange. The two sensors are outside but at different locations.


The software am2315.lua and am2316_mqtt.lua is on Sourceforge and Github.


NodeMCU for the ESP32?

Espressif dveloped the ESP32 and NodeMCU users wait for this more performance offering CPU. The information is rare, yet.

In the NodeMCU repository on Github I found some discussion about the state of development and this nice diagram revealing some internals and peripherals.


It would be nice to hold this device programmed with NodeMCU firmware in hands asap. If you have further information please add it to get a better picture of what we can expect.

I received an interesting link from DIY India Magazine with some more information.

NodeMCU for the ESP32?

Rainbow Colors on WS2812

To set the right colors for an RGB LED we have to set the appropriate values for R(ed), G(reen) and B(lue).

colorsOn this website I found this image explaining the composition of colored light from R, G and B.

You can step over the ratio axis and can generate all colors building a rainbow beginning from Red over Yellow, Green and Blue to Magenta and back to Red again.

If you start with three data points then you will get Red (0), Green (1/3) and Blue (2/3) only. The more equidistant data points are used, the finer the color gradation.

The required data points can be calculated with the Cosinus function to get a table of RGB values for controlling a RGB LED or Neopixels etc.

Continue reading “Rainbow Colors on WS2812”

Rainbow Colors on WS2812

IOT Button (3rd)

I started the test after building this test environment:

IoT_NodeThree Energizer max AA cells power the IoT Node. Normally the IoT Node sleeps.

After pressing the reset button the IoT Node is connecting to the home network via Wifi, measured the battery voltage, and send a message to IFTTT.

There are two IFTTT receipts. One sends a Twitter direct message (to me) and the other makes an entry into a Google spreadsheet.  Follow the link to see decharging my power pack by this IoT button app.

IOT Button (3rd)

IoT Button

Amazon introduces its Dash Button to order much needed goods. But there are alternatives. Two of them are and flic. and flic are just what the name suggests: connected push buttons that can trigger actions. Together with IFTTT they can trigger a growing number of services. Relating to the connectivity and flic differ.

The has built-in internet connectivity and needs no smartphones or apps to pair with. Flic uses a Bluetooth low energy connection to an Android or iOS smart phone and the flic app for network connection.

D1 mini button shieldThese offers are interesting to experiment with. But, we can build such an IoT Button by yourself and save a lot of money.

D1 mini combined with an 1-Button shield is one solution. You can buy both for $ 4.99 from Aliexpress.

Button Twitter

IFTTT offers channels for and flic. IFTTT’s Maker Channel allows you to connect IFTTT to your personal projects like this IoT Button.

This time my IoT Button sends a Twitter Direct Message after pressing it. It’s a starting point to test the mechanism.

The configuration of IFTTT is well documented and should be no problem.

For a door contact application step-by-step instructions for IFTTT setup are in my book “IoT Node for les than 15 $”.

This time I work on reducing power consumption to get a battery-powered solution.

IoT Button