Eric built himself a battery monitoring system based on the ATmega328 Development Kit. He drained a 9V battery with 100mA of current and monitored the voltage drop until total depletion. He used this data to estimate how much time is left until depletion – [via]
The 100mA constant load was chosen because my ProtoStack Arduino Clone with LCD draws about 92mA and I wanted to write a sketch to display a battery bar and the approximate hours battery life left. Since all batteries have an internal equivalent series resistance (ESR), it is important to take that into account when only using a battery’s voltage to monitor its state of charge. Since we discharged the battery through a load that is similar to the ProtoStack board with LCD, the ESR of the battery has automatically been accounted for in the voltage measurements.
Monitoring battery voltage to calculate capacity with an Arduino - [Link]
Here (machine translation) is a DIY single-layer version of the Arduino Leonardo. The blogger goes into detail on how to build one yourself. Everything is covered from preparing and etching your own DIY board, to fine pitch soldering of the ATmega32u4 IC. Once you have built your board, they show you how to upload a bootloader into the microcontroller.
The Arduino Leonardo is a new platform from the Arduino team that uses the ATmega32U4 uC with built in USB capability. This eliminates the need for the expensive FTDI USB-to-serial ICs and keeps the costs down.
DIY Arduino Leonardo clone - [Link]
If your Arduino project has minimal IO needs, you may want to consider shrinkifying it. This video demonstrates High Low Tech’s method for programming an ATTiny with Arduino code. Maker Randy Sarafan has designed an 8-pin Arduino programming shield to make the task easier. [via]
Shrinkify your Arduino project - [Link]
Don built an Amblight for his home theater PC. He put together this tutorial describing his build of a multichannel Arduino-based Ambilight. He estimates the BOM at $40 (in addition to the Arduino). [via]
The bill of materials include 6+ ShiftBrites (your call, I wouldn’t do less than 6 though), a printed circuit board, wire, and headers. Additionally this will require all of the components needed to get over 0.5 Amps at 5.5-9V DC on to the board to drive the ShiftBrites; this cannot be reasonably done over USB power. My ultimate goal here is to give others some ideas on how to go about this project for less money than it would cost to essentially buy everything in a kit. I went in to this trying to be resourceful and I feel pretty good about how it turned out.
DIY Arduino Ambilight using ShiftBrites - [Link]
Goal is to replace this Ikea super cheap timer that works … well, as good as something manual that you paied less than 200 JPY (less than 2 euro). Not precise, sometimes doesn’t ring, or ring just the blink of an eye, so easy to miss…
The new timer will:
- Have a graphical LCD (bought one one year ago, never used it, needed a pretext, so…)
- Work on battery (1x 9v battery)
- Play music when it’s time
- Use a speaker and amp
- Possibly use a YMZ294 ?
- In fact something else but much better…
- Have an on/off system with a push-button, not a open/close switch In fact a tilt switch
- No arduino, but a simple atmega 328 (more than sufficient)
- Keep me busy a few days while allowing me to use some parts I bought long time ago and create a un-reasonable and out of price kitchen timer
Arduino KitchenTimer - [Link]
Jaanus has been working on a subminiature Arduino clone which be believes is THE smallest – [via]
Everybody are making Arduino clones. So I thought I should make THE smallest. I took smallest package atmega88 – qnf28 (5mm x 5mm). Routed smallest possible resonator and as much pads as i could fit on in.
His design provides SPI, UART, one LED and breaks out 4 analog and 1 digital IO pins.
tinyDino – smallest Arduino board - [Link]
Remembering to take a vitamin daily is simple enough. Remember to take a vitamin every three days is nearly impossible (for me). I wanted a solution which will remind me to take the pill and require zero effort. This small project holds two bottles in a fairly nice looking box and flashes red until you take the pill. The act of picking up the bottle (the pill ingestion is assumed) is the entire interface.
Arduino vitamin – pill reminder - [Link]
One of the first companies to focus on Wi-Fi was the AsyncLabs, who proposed a famous WiFi shield, including the appropriate libraries. What we propose is a new solution for Wi-Fi: this is a shield that the hardware was inspired by that of AsyncLabs, but in addition, we have provided a slot for microSD memory.
The basic component of the shield that we have made is a Wi-Fi module MRF24WB0MA manufactured by Microchip. The device is a Wi-Fi IEEE 802.11 RF transceiver, with a data rate between 1 and 2 Mbps, and with an internal antenna.
The WiFi shield supports both types of wireless networks infrastructure (BSS) and ad-hoc (IBSS) and is also allowed to connect to secure networks (cryptographers and are supported 64 and 128-bit WEP, WPA/WPA2 and TKIP, AES and PSK).
The library is constantly evolving, so we have provided a space where they will be published on http://code.google.com/p/wifi-shield-oe/ various versions available. http://www.open-electronics.org/arduino-wifi-shield/
Arduino WiFi Shield - [Link]
Andrea Belloni writes:
We realized this project for the “Arduino Day” in Rome 14/04/2011. For it we used two JeeNode (Arduino variant with wireless module on-board), one Rainbowduino + RGB LED Matrix and one PC with Processing. The Processing sketch generate the “plasma” animation and sends the images stream to the first JeeNode via serial port. This JeeNode receives the images and sends it to the second JeeNode via wireless link. The second JeeNode receives the images and sends it to the Rainbowduino + RGB LED Matrix via i2c. More details on the blog’s post (for the English version scroll down).
Wireless pixels - [Link]
Moser from ReiBot has developed a simple project for using an Arduino along with an LM399 and several discrete components to measure inductance. He says: [via]
So you need to make or measure an inductor, but you don’t have an oscilloscope or signal generator? Measuring inductance with a handful of cheap common parts is certainly possible. I’ve verified this method is accurate with a scope from 80uH to 30,000uH, but it should work for inductors a bit smaller or much larger.
Easily measure inductance using Arduino - [Link]