DHT22 accuracy test part 2/2

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 data…Got Data 25.50C 75.20% Integer-only reading: Temperature 25.5 C, Humidity 75.2 % RH Requesting data…Got…

DHT22 accuracy test part 1

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 causing the issues. He sent me a 3D printed Stevenson screen to try, but I…

Cheap DIY power monitor

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 used a SCT-013-000 current transformer to sense the current and a 9V transformer to sense…

Scope screenshots

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 using the voltage drop over a resistor (supposedly 10 ohm, but my multimer measures it as…

Oscilloscope

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. So I got it yesterday evening and had to explore it. I have never before…

Soil moisture sensing revisited

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 – using an Analog input with the internal pull-up enabled:   That pretty much simplifies…

RFM12B End of Life

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 news that the RFM12B module has been declared in its End of Life. There has been…

Wallpaper prank

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 upon a project called “USB Ducky“; One of the example uses was to use the…