NavSpark versus NS-RAW

Today I received the NavSpark and two NS-RAW GPS receivers I preordered from SkyTraq back in January. The NavSpark is a programmable SPARC-based GPS receiver, while the NS-RAW is one of the cheapest GPS receivers available with raw measurement output for RTK positioning. In recent months, it became clear that the two receivers would be virtually identical hardware-wise, just with different firmware.

On receiving the boards, the first thing I did was look for the differences. The most obvious difference is that the NavSpark has version 1.4 of the PCB, while the NS-RAW is built using version 1.3. The only difference I could find between the revisions is that version 1.3 left out the pull-up resistor on the SDA I2C line. SkyTraq seems to have used the flawed boards for the NS-RAW since it is not supposed to be programmable and thus won’t make use of I2C. This extra resistor can be seen below; version 1.3 is on the left, while version 1.4 is on the right.

Version 1.3 (left) versus 1.4 (right) Continue reading

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CHDK on the Canon PowerShot ELPH 330 HS

I recently purchased a Canon PowerShot ELPH 330 HS point and shoot camera to replace my aging Canon PowerShot SD770 IS. The new camera has better sensitivity, a considerably wider field of view that will help with aerial photography, and more zoom. However, it did not have CHDK available for it, which I was aware of at the time of purchase. The first thing I did on receipt of the camera was begin porting CHDK to it. A few weeks later, the port was mostly done, and it was recently merged into the trunk.

Canon PowerShot ELPH 330 HS with CHDK

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Quadcopter Landing Skids

One of my quadcopters recently had a hard landing that broke its landing skids. The skids that came with the frame kit consisted of 5mm carbon rods with flimsy plastic joints, and the crash broke both. I decided to replace the skids with a more durable pair by replacing the carbon rods with aluminum and the plastic joints with sturdier 3D-printed ones.

Landing Skid Joint

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Snowy JHU Aerial Photos

These photos were taken at Johns Hopkins’ Homewood Campus from a quadcopter the day after a snow storm.

MSE Library

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HTML5 Night Sky Viewer

For HopHacks last weekend, I wrote an HTML5 night sky viewer. Using D3.js and SunCalc, the 750 brightest stars are rendered using SVG and Javascript. One’s location can either be found using the HTML5 Geolocation API, or it can be entered manually. The keyboard is used to navigate, and mousing over a star will display some information about it. As it was written in a weekend, there may be bugs.

Here is the viewer:
http://mpetroff.net/files/nightsky/

The code is available on Github.

Night Sky

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