As part of a project to make DIY water activated diving flashing marker, I needed a simple circuit to detect when the marker is in contact with water. Turns all all it takes to do that is a a couple of basic components. Here is the diagram; P1 and P2 are the probes that will be in contact with water: Water detection circuit ...
I was looking for an option to create a circuit with a switch, so I can use two single cell li-on Nokia cell phone batteries in series, but charge them in parallel through a USB charger. The idea is to be able to install the batteries in a small robot, where they will not be easily accessible to charge with my regular li-po battery charger. I have a couple of these simple but effective battery chargers lying around, but they can only charge a single cell. After some digging around, I found the following circuit and was able to successfully to put it together and test it. You need a “double-pole-double-throw” (DPDT) switches. It is a switch with six pins, essentially two single switches with a common button / slider. The two sides of the switch are not connected and control two separate circuits. So here is what you need: ...
After testing the basic Wi-Fi connectivity options of the ESP8266 it is now time to explore some of the more interesting features of the chip. In the sketch below the NodeMCU development board creates a Wi-Fi access point and starts a web-server. A HTML page hosted on the web-server displays analog data from a photocell and allows you to control remotely a LED via Wi-Fi from a web-browser on your phone or PC. As in the previous examples, I am using the Arduino IDE to program the ESP8266 board. ...
In the following examples, I will be using the NodeMCU development board and will program it with the Arduino software. Hopefully you have already set-up your ESP8266 development environment and were able to load the blink sketch. If not please follow this tutorial first. ESP8266 WiFi station mode example The ESP8266 can communicate over WiFi in two different modes. It can connect to an existing wireless hot spot, or access point, similar to the way you connect your phone or computer to the Internet. This is called “station” mode. In station mode the ESP8266 board can reach out to the internet and may also communicate with other devices connected to the same network, including other ESP8266 modules. Here is a simple example. Remember to replace the values for the ssid and password variables with the name and password for your wireless network! ...
Part 1 of this tutorial covers the set-up of the Arduino IDE to support the ESP8266 boards. In part 2 I will go through the steps of loading a slightly modified Blink sketch to the NodeMCU board. First, a couple of things to be aware of when working with the ESP8266 boards: Power: ESP8266 is a 3.3v board The NodeMCU version of the board has an on-board 3.3v voltage regulator and can be powered from the USB port (5V), or through the vin pin (5-7.5v recommended). All GPIO pins work at 3.3v and the board may be damaged, when connected directly to 5v Arduino compatible modules. Additionally, the maximum current that can be sourced from a digital pin is 12 mA. Use a high value resistor for LEDs (1k Ohm) and do not connect servos, motors, or other peripherals that draw large current. ...
I have recently started exploring an ESP8266 based development board I had sitting around. There is a growing number of firmware and development tools for the board, but as I am familiar with the Arduino IDE and syntax, I decided to give it a shot first. If you are familiar with Lua, you might be more comfortable checking out the NodeMCU project. Those guys created an open source hardware development board around the ESP8266 MCU with included USB interface for easy programming and power and custom firmware and development tool-chain to program the ESP8266 module using Lua. ...
ESP8266 Introduction The ESP8266 is a low cost MCU with built in Wi-Fi. It can be paired with another host microcontroller, like an Arduino, to provide WiFi networking capability for a basic IoT development platform. Additionally, the ESP8266 can be used as a stand-alone MCU, as it includes a 32-bit 80Mhz processor, 16 GPIO pins (4 PWM enabled) and a built in Analog-to-Digital converter, SPI and I2C interfaces and more… The MCU has a n operating voltage of 2.5V – 3.6V and average operating current of 80 mA. Here is the official ESP8266 MCU datasheet from the Shangai-based manufacturer of the chip Espressif Systems. The most popular current version is the ESP-12E MCU pictured below. On its own this is not very friendly for prototyping, as the spacing of the pins is not compatible with standard headers and breadboards. ...
After a lot of reading and drooling over various 3d printers, I finally pulled the trigger and got myself one: the Monoprice Select Mini 3D. This is a budget printer and the design was focused on low price, versus performance and speed. I am not interested in producing large, very artistic, or decorative prints, so this is not a problem for me. Monoprice Select Mini 3d printer ...
The “World’s Largest Arduino Maker Challenge” is happening right now through a partnership between Hackster.io, Atmel, Adafruit, Arduino and Microsoft. Here is a video presentation of the context by Massimo Banzi, CEO of Arduino.cc: The contest will run in multiple phases, the first being an idea submission, by January 15th, 2015. A 1,000 lucky makers with the best proposals will win the newly released Arduino MKR1000 (US only) and Genuino MKR1000 (Outside US) boards that is scheduled to come out on the market in February, 2016. ...
In previous posts I covered the steps on programming ATtiny85 and ATtiny84 chips using an Arduino Uno as programmer and the Arduino IDE Software with two different “libraries”. At that time the process of adding new boards to the Arduino IDE was fairly complicated and manual. As of version 1.6.4 of the Arduino IDE, the “Boards Manager” has been added, which makes adding third party boards (like the ATtiny) much easier. The awesome guys at the MIT Labs High-Low tech group have created the required file for the ATtiny ICS (ATtiny85, 45, 84 and 44) and provided installation instructions on their site. The video tutorial below covers the steps from setting up the Arduinp IDE and configuring the Arduino Uno to act as a programmer, through wiring the ATtiny to the Arduino, uploading a test sketch (“blink”, of course) and configuring the ATtiny to use its internal 8 Mhz clock. ...