I accidentally landed on a site called ‘quantified self’ last month and immediately realized I am doing lots of lifelogging myself. I track my commutes, log my weight, my body temperature when sick, my hot water usage habits, visitors to…
I was thinking about the accuracy of the battery measurements the other day, are these accurate or not? I measured the battery using Fluke 27 multimeter and compared that to the readout using the internal bangap method and found a small difference.…
Alex from insideGadgets had an interesting project last year on non-contact AC detection and I wanted to try it out and learn how it works. He hooked one leg of a 1M ohm resistor to GND and a wire to…
I have measured the relative humidity as per my set up, and got steady readouts exactly in the 75% area as expected: DHT22 Library Demo Requesting data…Got Data 25.50C 75.20% Integer-only reading: Temperature 25.5 C, Humidity 75.2 % RH Requesting…
I have been boggled for a while about the Relative Humidity data that I gather, I get some higher than expected reading. I blogged about this in this post and @Dimitrios suggested in the comments that my box my be…
My father asked me to create a standalone power monitor for him, he’d like attach it to some appliance and see its momentary and accumulated over time power consumption. Using OpenEnergyMonitor’s resources that was an easy task to do. I…
I have mentioned before, that I have purchased couple nRF24L01+ units from eBay for the stunning $3 with delivery included. I decided to make some cheap tests this time, so went for a veroboard prototype. I got two blank DIP…
I have a cheap USB to 3.3V TTL FTDI Cable that I bought on Ebay. It has been giving me some troubles ever since I got it, burned couple RFM12B modules along the way. I decided to hook it to…
One of the cool things about having a digital scope is that you can take screenshots and post them in blogs :). I wanted to check how a Funky v2 was behaving, so hooked one to measure its current consumption…
I have finally decided to get myself an oscilloscope, my choice ended up to be a Rigol DS1052E. The model seems to be pretty popular, and for a price tag of 309 EUR with delivery, I could no longer resist.…
I have previously created a DIY soil moisture sensor, but wiring it required couple resistors. I was recently reading a post by JCW on using a light sensor and figured I could simplify my setup using the same basic idea…
EDIT March 2015: [It has been two years since this post, and the RFM12B is still widely available. I guess the rumors at that time were exaggerated widely.] There has been bad news for the RFM12B ecosystem last week, namely the…
I wish I did this for April 1st, but here is it anyway 🙂 I wanted to test out the HID keyboard features of the Arduino Leonardo compatible Funky v2, so during my research on the subject I accidentally stumbled…
I got myself a 1.8″ TFT LCD display from ebay, attracted by the low price. The display also has a SD card slot. It comes without any documentation and you are presented the joys of figuring out how to drive it…
I noticed this Instructable the other day and had to try it since I had an old USB web cam laying around. I found that the instructions contained some inaccuracies, here are my steps: sudo apt-get install motion sudo nano /etc/motion/motion.conf Locate…