PIC32 – Custom Development Board (Part I: Design/Hardware)

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The IcePIC is the first substantial project I worked on after the my decision to commit to learning digital design and embedded systems. I brushed up on my skills in Altium acquired from my time working as a summer program instructor at McMaster University, and I applied those skills in conjunction (along with a lot of research on the PIC!) in order to begin this project.

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PSoC – AM Radio Transmitter

AM Transmitter with just a dev-kit!
AM Transmitter with just a dev-kit!

Previously, I wrote about the Cypress PSoC5LP microcontroller that I have been playing with. The CY8C5888LTI-LP097 on the CY8CKIT-059 dev-kit can be used to make a very crude radio transmitter. Today I will be explaining how to make some simple transmissions from a PSoC to a computer equipped with an RTL-SDR and SDR# acting as our radio receiver. We will be using configurable digital hardware to create the transmitter.

NOTE: If you decide to recreate my experiment, you should take a look at your country’s regulations for radio communicating devices. For example, the FCC in the United States allows hobbyists to create and operate up to 5 low power devices without a license as long as you follow some rules. Still, be responsible and don’t operate this for any longer then you need to know it works.

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PSoC – Intro and Clock Configuration

Top an IMO derived clock not synchronized to MCLK also acting as the edge trigger. Bottom IMO derived clock synchronized to MCLK.
Top an IMO derived clock not synchronized to MCLK also acting as the edge trigger. Bottom IMO derived clock synchronized to MCLK.

I recently picked up a Cypress CY8CKIT-059 to play with for about $10 from Mouser. The kit contains a CY8C5888LTI-LP097 chip that features an ARM Cortex M3 that can run up to 80 Mhz, pretty run of the mill. However, the chip also features a small amount of CPLD resources and configurable datapaths that can be used to implement any digital logic that you can fit in. Cypress calls these blocks universal digital blocks. You can implement your own logic blocks in Verilog or use Cypress’s IP cores that are included with PSoC Creator. The idea is to avoid predefining how many UART, I2C, SPI or other interfaces to include which gives you more freedom to choose the combinations of peripherals you need rather than using pin muxes like on Microchip PIC’s and Atmel AVR’s for example. With the PSoC 5LP you can have 5 UARTs if you wanted and you can put those UARTs on any GPIO pin you want.

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Is a higher Megapixel count always better?

With the news that the new IPhone 6s might include a higher megapixel (12MP) camera than its predecessor, I decided that it might be fun to explore how much the amount of megapixels in a camera affect the quality of the photo. It is frequently used as one of the sole metrics to evaluate the performance of a digital camera. Is this a reliable number to go by, or is there more to picking out a “good” camera than just looking at the amount of pixels?

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Head Related Transfer Functions and Headphone Listening

Switchfoot-fft
Fast fourier transform output of the first 15 seconds of Switchfoot – Meant to Live. The left channel is displayed on top and the right channel on the bottom. This clearly displays extreme stereo separation.

Listening to stereo music through headphones has never sounded quite right to me. The extreme stereo separation can cause headaches for me when using headphones for more than an hour. Some people report experiencing “pressure” in their ears when using headphones This discomfort could simply be due to how unnatural headphone listening is; no sound from the left channel makes it to your right ear and vice versa. There are some tricks that can be used to get rid of these problems but before I show you how you can try out these tricks let’s get into the math and science behind head related transfer function (HRTF) and how they are used to simulate the way sound travels to our ears resulting in a better listening experience when using headphones with stereo content or even create what is known as virtual surround sound. Continue reading Head Related Transfer Functions and Headphone Listening