Showing all posts by jhottell

Homemade  bubble machine complete with variable speed bubble wand, variable speed fan. PID loop controlled heaters to heat the air to give the bubbles more lift.


  • 150W PC power supply
  • Fan: NIDEC BetaV M# 35291-35 2.3A
  • EZ HEat 300W band heater 1.5”
  • PID controller REX-C100
  • 12 Volt gear motor from Tokyo Micro
  • Fotek Solid State Relay SSR-25DA

Here is the 3d printer file for the bubble wand holder…

TI LaunchPad MQTT I/O Demo

This demo connects two TI LaunchPad devices together using MQTT. I have every intention to add other devices to the mix like Arduino, Netduino, RaspBerry Pi, and BeagleBone in the future.


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HC-21 Simple Wifi Serial for Arduino Tutorial

The Simple Wi-Fi HC-21 module is a meager $10-$15 bucks on ebay right now. It is a simple Wi-Fi serial port server or virtual serial port. This means it is self contained and will handleimage all the overhead of negotiating a Wi-Fi connection and communication leaving more room for your application in the Arduino.

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Arduino error: expected unqualified-id before numeric constant

error: expected unqualified-id before numeric constant

This Arduino IDE error blew my mind for a while, come to find out it can be caused from syntax errors. look for a missing semi colon or accidental text at the top of your sketch.

The Error

Thermostat1:1: error: expected unqualified-id before numeric constant
In file included from Thermostat1.ino:9: Read More…

DIY Arduino Mini BMO

Arduino Mini BMO

BMO from Comedy Central’s Adventure Time is adorable, if only someone would make one that can walk! Atleast we can make one with a personality. Here is a build using easy to get parts including Arduino Pro Mini, Nokia 3310 LCD screen, audio playback, accelerometers, and distance sensors.  Read More…

X10 Control Using Arduino, Modbus, and ScadaBR

X10 Lighting and appliance modules are cheap on Ebay, I wanted to control them with my HMI (ScadaBR) so I put a X10 and Modbus library together in an  Arduino to turn on and off the modules.

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How To Scale A Thermistor for An Arduino

Thermistors And Your Microcontroller

A thermistor is a simple temperature component, basically it is a variable resistor that the resistance changes in it depending on the temperature. Such a simple device needs a few more components and scaling in the microcontroller to give the desired C or F temperature reading.

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Arduino Modbus PLC / RTU


A Programmable Logic Controller, PLC or Programmable Controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures. PLCs are used in many industries and machines.

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Home Automation HMI with Mango M2M


A HMI (Human Machine Interface) is the system by which people can interact with a machine. The user interface includes hardware (physical) and software (logical) components.

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Kossel Mini 3D Printer Accessories and Modifications

Here are some 3D printer accessories and modifications I couldn’t live without.

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