Measure Bike Speed with PocketCHIP and GPS Receiver

I won a #FreePocketCHIP last Christmas. It is a "pocketable" Linux computer running Debian, and has one USB 2.0 host port. Apart from adding a speaker and playing PICO-8 games, PocketCHIP's form factor and hackability make it suitable for many other projects. Today, I'm going to find out how fast I am riding a bike, with the PocketC.H.I.P and VK-172 GPS receiver.

PocketCHIP and VK-172 GPS receiver

Meet the GPS Receiver

The GPS receiver I have is the VK-172 G-mouse USB GPS receiver. It has a small form factor, and connects to the PocketCHIP via USB. When connected, it identifies itself as a USB device with ID 1546:01a7, and shows up as a serial port:

Access C.H.I.P UART Wirelessly with ESP8266

A year ago, a Kickstarter campaign CHIP - The World's First Nine Dollar Computer caught my attention: it's a $9 computer smaller than a banana. Unlikely the Raspberry Pi, it comes with onboard storage so I don't need to buy a separate SD card, it has WiFi instead of wired Ethernet so I don't have to run wires everywhere, and it is compatible with my existing VGA monitor through a $10 adaptor so I don't have to buy another HDMI monitor. Therefore, I snapped two of these little computer along with one VGA adapter during the campaign.

During the whole year of waiting, Next Thing Co sends me regular email updates on the development progress, with each email ending with mmmtc (much much more to come) and a lot of hearts. NTC also clarified that C.H.I.P is strictly B.Y.O.B. Finally, my pair of CHIPs and a VGA DIP arrived in my mailbox on Jun 16. An hour later, yoursunny.com homepage is displayed on its Debian desktop.

A few more hours later, I start to discover a limitation of C.H.I.P software: The Linux kernel comes with CHIP operating system has very limited features.

$ sudo modprobe fuse
modprobe: FATAL: Module fuse not found.

Obviously, the solution to this problem is to compile my own Linux kernel with more features. The compilation can be done on the C.H.I.P itself. I managed to do that when the CHIP is powered by a 5V 1A phone charger plus a 1500mAh LiPo battery. I had the compilation running under screen(1) and attended to it intermittently, and finished in a day.