I’m working on several projects that I want to include a voltmeter to monitor battery levels. One of the easier methods is to use a resistor voltage divider network and a zener diode to scale the input voltage to a value safe for the Analog-to-Digital (ADC) pin. I developed a voltage divider calculator in C# to help me determine the correct resistor values for the selected voltage range I would like to measure. You can find it here.
Year: 2011
Software – Arduino TFT Touchscreen RGB Color Mixer
Adafruit sells a really nice touchscreen and shield for the Arduino (other microcontrollers welcome). They also provide a library for the Arduino that makes the touchscreen easy to use. I want to use the touchscreen to develop some custom menus but, found it difficult to figure out RGB color codes. So, I wrote a little C# program to take care of that for me. You can find it here.
General – Arduino Optiboot Boot-loader
I’ll soon be updating the Hobbyduino Mini to the Optiboot boot-loader. According to the Optiboot Google Code Page:
- Allows larger sketches.
- Is a quarter of the size of the default bootloader freeing 1.5k of extra space.
- Sketches upload faster.
- Optiboot operates at higher baud rates and has streamlined programming.
- Adaboot performance improvements.
- Runs sketches sooner with no watchdog issues.
- Compatible with 168 and 328 Arduinos.
Project – Hobbybotics Motor Controller V1.0
I designed a basic motor controller that is robust, cost effective and able to handle high current. I wanted to take advantage of Pulse Width Modulation (PWM) to allow speed control but keep direction control as simple as possible. Thus, I use a pair of SPDT relays for direction and a single MOSFET for PWM. I also use optoisolation to separate digital logic from the back EMF of the motor and relay coils. Go here to see it.
Project – Hobbyduino Proto Plug V2.0
I developed the prototype plug to further extend the mounting options for the Hobbyduino. A breadboard can be mounted for prototyping or components can be soldered onto the board. Go here to see it.
Gallery – Hobbyduino Proto Plug V2.0
More mounting options! I have developed a prototype shield in my pursuit to make it easier to use the Hobbyduino. This shield allows a breadboard to be mounted on it for prototyping circuits. It also has a circuit layout in reference to a breadboard that allows for permanent mounted circuits. Go here to see it.
Project – Hobbyduino Mini Screw Plug V1.0
I wanted to expand the mounting options for the Hobbyduino Mini so, I created a screw terminal shield. This shield breaks out the Arduino pins to screw terminals and allows for easy attachment of wires. Go here for the project.
Links – Arduino High-Altitude Ballooning (HAB)
I would love to get into near-space exploration projects. One of the more cost effective approaches is with High-Altitude Ballooning (HAB).
High-altitude balloons are unmanned balloons, usually filled with helium or hydrogen that are released into the stratosphere. They generally reach an altitude between 60,000 to 120,000 feet (18 to 37 km).
Two open source projects that I came across are the Sparkfun HAB by Nate and Trackuino project by Javier Martin. Kyle Crocke has developed an Arduino shield based off the the Trackuino project. I’ll be studying the above designs so that I can start experimenting.
Original Post: Adafruit
Links – Finding Parts
Designing a circuit board is only part of finishing a project. Finding components is probably one of the most tedious and mundane tasks. Adafruit put together an article and identified some sources for finding parts. This will come in handy in those situations where your primary vendor is out of a specific component you need. I usually purchase my parts from either Sparkfun, Digikey, Jameco, and/or Mouser.
Read about it here: Adafruit: Finding Parts
Links – PCB Fabrication Sources
There are numerous choices when it comes to picking a PCB fabrication company. I’ve been using ExpressPCB since their software is very easy to use. The problem with ExpressPCB is the software is proprietary to their manufacturing services. They do allow you the opportunity to purchase your board files in order to have them produced by other PCB fabrication companies, however, you have to purchase a set from them first.
There are other popular options for schematic/PCB software that does not lock you into their services. Two popular applications are Eagle and Diptrace. The problem is deciding what fabrication company to use in order to have your boards produced. Digital DIY has put together an in-depth article comparing some of the many services that are offered.
Read about it here: Digital DIY
Hobbybotics 