So, I’m at the point with the Flavonoid project that I need to start getting printed circuit boards made. (The printed circuit board includes an accelerometer, a real-time clock, touch sensor, and a bit of EEPROM memory, if you want to know.) A fair bit of the break was spent schooling up on Eagle, doing layouts, making mistakes and that sort of thing. (It’s remarkably full-featured for a free product and, despite a few quirks, does what it says it will do. Plenty of activity in the forums and help is quick to come when I’ve gotten in trouble.)As I closed in on a design I thought was close enough to gold to send off, I started poking around various forums to find out what operation might be suitable for small (1-10 piece) runs.
Printed Circuit Board Fab Houses – A Few Reviews – [Link]
I’ve been fussing with this digital potentiometer, the DS1803 by Maxim. They’re “digital” because you can control the resistance over its range programmatically, by sending it commands over a 2-Wire (I2C/TWI) serial interface. So, that means that I can hook it up to some microcontroller, like the Arduino, and adjust the resistance in a little program. I chose this one in particular because it can operate at either 3V or 5V, which is convenient, and it comes in a few different models with various resistance ranges. I’m using the DS1803-010, which means it has a range of 0-10K Ohms
DS1803 Digital Potentiometer – [Link]
This DIYThermocouple project uses a MAX6675 chip and takes the millivolts produced by a standard K-type thermocouple, amplifies it, and spits out the results to the attached LCD screen. This particular unit can read temperatures up to 1800 degrees Fahrenheit which is probably hotter that you ever want to be near with your electronics. [via]
Thermocouple project won’t get you burnt – [Link]
An automatic blind opener is not a new invention. They have been available for years. However, even the low end models cost in excess of a hundred dollars per window. Some models and styles can cost ten times that much. Most use IR remote controls. Other available activation options include timers, RS-232 interfaces, and light sensors. I needed a controller with a light sensor that would open my blinds in the mornings and close then in the evenings. However, I was not willing to pay what I thought was an unreasonable price for a simple light activated motor. Being the Maker that I am, I knew I could design and build what I needed and do it for a lot less money than what any commercial units cost.
Build A Motorized Window Blinds Controller - [Link]
This is a simple do-it-yourself (DIY) headphone amplifier project that is fashioned primarily after the Class A MOSFET Headphone Driver project by Greg Szekeres and to some extent Mark’s DIY Class A 2SK1058 MOSFET Amplifier Project. The amplifier concept is simple and follows a typical single-ended class A circuit utilizing an active constant current source (CCS) in place of a passive resistor. A CCS doubles the efficiency of the circuit over that where a passive load resistor is used, bringing it to a maximum of 25%.
Class A headphone amplifier in a CD-ROM case - [Link]
I’m still working on the LED calculator — I’ve finally got ’round to adding a rotary encoder to set the target system voltage. Now you can turn the potentiometer to set the LED brightness, turn the rotary encoder to set what voltage will be used in the ultimate LED circuit, and read the LED voltage, current, and current-limiting resistor values off the screen.
LED Calculator with Rotary Encoder - [Link]
This software allows you to get a visual representation of an analog signal using Arduino and Processing. The resolution is 10 bits so this is not like a real oscilloscope but it is still pretty useful. It works by sending values read from the Arduino board (pin 0) to Processing through serial communication.
Poorman’s oscilloscope (with Arduino + Processing) - [Link]
This Portable Universal Radiation Spectrum Analyzer has many advanced features based upon the experience gained from the original design by Wedemeyer. The signal to noise ratio is significantly higher and therefore reduces count time as well as allowing a better low end range, high end range is of course as good as ever.
Portable Universal Radiation Spectrum Analyzer - [Link]