Wireless body temperature monitor/logger

I have been experimenting the last couple days with a wearable electronics project – a wireless body temperature monitor/logger. The idea is to remotely monitor kids body temperature, if they are sick, and put up a status display with alarm function in our bedroom. The remote monitor will be another Funky with RGB LED for…

OLED analog clock

I have updated my OLED status display project with an option for analog clock: I also experimented with drawing bitmaps, a thermometer is drawn to the right of the clock face that changes its reading according to the solar water tank temperature. Time and temperature are captured from the wireless packets of telemetry floating around…

Reducing RFM12B transmission power

@Dimitrios noted something very important in the comments to an earlier my post on low-power sketch: One of the things I noticed when I started playing with the RFM12B module was that the receiver front end was mostly overloaded by the strong transmitter output (1~ 5dBm). This has a negative effect in the quality of…

Optimizing DS18B20 code for low power applications

I have been uneasy with the conversion time that the DS18B20 temperature sensors have,  it is 750 ms when using the 12-bit resolution: The 12-bit resolution is the default power-on, so when powering the sensor from a digital pin, you always end up in 12-bit resolution (this is the typical approach when a sensor is…

Miniature OLED status display with Funky v2

I purchased a small serial OLED display few weeks ago, it showed up yesterday at the mail box. Dimensions of the PCB are (WxHxD):30x28x4.8mm (1.2X1.1×0.19″) and the display itself is 22x12mm with 128×64 pixels. Pixels are really bright and viewing angle is close to 180 degrees, perfectly view-able at bright sunlight. I measured the power…

Funky v2 now poses as LilyPad Arduino USB

In an effort to make the Funky v2 even easier to use, I decided to make it appear as a standard LilyPad Arduino USB by using the same USB VID/PID pair. This will enable using it with Arduino IDE without needing to modify it, all this is possible because the Funky v2 and Lilypad Arduino USB…

Crazy high frequency PWM with ATMega32U4

Timer 4 on the ATMega32U4 is a high speed one, but I have never tried it out before. Now that I have a scope, I decided to toy with it. It can work from the internal PLL, meaning some really high frequencies can be achieved. I managed to get up to 8Mhz, but probably more can be…