Amplitude and frequency modulation

Do you know how AM/FM radio works?

Serial Communication Demystified - According to Pete

Brushing up on serial communication basics. Been experimenting with radio communication.

Wireless devices go battery-free with new communication technique

This title might be a little misleading. However, this is an interesting article about some University of Washington students who've created an RFID-like communication method that doesn't require active transmission. Check it out: Wireless devices go battery-free with new communication technique

Passive RC filter tutorials

Capacitance measurements

Recently I've been focusing on a project I'm calling LibreTester. It's an open hardware Arduino-based component tester. It measures transistors, capacitors, resistors, and diodes. However I've been having trouble measuring small capacitances. Hack-A-Day posted about this fellow who was measuring very small capacitance accurately.

Adafruit - an open source software/hardware role model

I felt like posting about the open source software/hardware company Adafruit located in NY. They are a wonderful company that produces excellent learning material for hardware enthusiasts/hackers. They are quite prolific in the amount and quality of content they produce and make available.

More 3D printed EDFs

I like these guys' designs. I wish they put out more videos.

1st results from the flywheel dynamometer project

Just completed a first prototype of the flywheel dynamometer. It currently measures RPM, from which angular acceleration, torque and power can be extracted. The plan is to measure voltage/current at the battery to determine motor efficiency. I'll release its Arduino source code and post-processing Octave/Python scripts shortly.

An RC motor dynamometer

My 3800KV brushless motor is only spinning up to 20,000rpm when paired with a 64mm fan which is no where near it's 40,000rpm no load speed (@11V). At the same time, the most power I'm drawing from it is about 100W instead of its rated 500W. This doesn't make sense to me; I'd expect that at 100W, the motor is lightly loaded. Why am I not able to spin faster and hence draw more power? The faster the fan turns, the more torque that must be overcome. I need to see this motor's power curves.

1969 US Air Force training video: AC Motors

Learning about AC motors so I thought I'd post this interesting educational video on the topic. RC brushless motors are usually 3-phase AC motors.

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