C3Pi - Fun and Frustration at the Elephant and Castle

By -
C3Pi from above

I went along this morning to the Elephant and Castle Mini Maker Faire to introduce C3Pi to some of my fellow makers.

The event was extremely well organised and I had no problem finding my desk and setting up. Before long C3Pi was running through his paces - fairly limited at the moment, as he still has no sensors and is controlled by a very simple command line interface.

That's about to change, thanks to Joe Walnes' brilliant websocketd - more details below.

In spite of his limited repertoire C3Pi soon made new friends and performed admirably. It's always a little nerve-wracking when he runs on a desktop. He has been known to get over-excited and career off in unexpected directions, but this morning he behaved himself...

Power problems

... until just before lunchtime, that is.

I'm still not certain what happened, but I think C3Pi's batteries ran low. What I know is that the ssh session connecting my laptop to the Pi suddenly started behaving strangely, and C3Pi's file system was completely corrupted.

There's quite a lot of work needed to recreate the file system and I had to take C3Pi home to repair the damage. Next time I'll prepare and take a backup SD card! I'll also trying out the Pi UPS which is designed to avoid just this sort of problem. By then C3Pi should aslo have a proper web interface.

A web interface using websocketd

I've wanted to provide a web interface to C3Pi for a while, but never got around to it. I am currently experimenting with a browser interface using websockets, based around Joe Walnes' websocketd interface.

websocketd makes it incredibly easy to web-socket enable any program that reads from standard input and/or writes to standard output.

There's an easy-to-follow example in the 10 second tutorial, with more detail in the 10 minute tutorial.

The software is really easy to install. It's a single, small stand-alone executable, with versions available for WIndows, OSX and Linux. The Linux versions include one for ARM processors and websocketd runs well on the Pi.

If you want a really simple way to control or observe stuff via a web browser, take a look at websocketd. Recommended.




Comments

Post a Comment

Popular posts from this blog

Controlling a Raspberry Pi Pico remotely using PySerial

By -
Image
Update : I'm using thie code below in another project, and found that I had not correctly fixed the reported bug. The new version passes automated tests, and I am pretty sure it works OK. I have changed the name of the class to Talker  since it can both send and receive information. Apologies to all concerned for the bug! Introduction You can use a Raspberry Pi Pico as a powerful peripheral to a host - a Raspberry Pi, a Jetson Nano, a laptop or workstation. In this article you'll see how to interact with a Pico running MicroPython or CircuitPython by writing some Python code that runs on the host. The software is easy to use. It enables you to send a Python statement to the Pico and read the results. The statement can be any valid MicroPython code. Setting up the host and the Pico For this article I've used a Raspberry Pi as the host, but any computer running Windows, Linux or Mac OS will do so long as it has Python 3.5 or later installed. In particular, you can use this t
Read more

Five steps to connect Jetson Nano and Arduino

By -
Image
Yesterday's post showed how to link a micro:bit to the Jetson Nano. One of the members of the (unofficial) NVIDIA Jetson Nano group on Facebook asked about connecting an Arduino to the Jetson. Here's a simple recipe for getting data from the Arduino to the Jetson Nano. It should work on all the Jetson models, not just the Nano, but I only have Nanos to hand. On request, I've added a recipe at the end of this post which sends data from the Jetson Nano to the Arduino; it turns the default LED on the Arduino on or off. The recipe for sending data from the Arduino to the Jetson has just 5 stages: Program the Arduino. (I used the ASCIITable example). Connect the Arduino to the Jetson using a USB connector Install pyserial on the Jetson Download a three-line Python script Run the script.   Programming the Arduino I used an Arduino Uno, and checked it on a verteran Duemilanove (above), but any Arduino should work. You'll need to do this step usi
Read more

Raspberry Pi Pico project 2 - MCP3008

By -
Image
This post show you how to drive the MCP3008 8-channel ADC using a Raspberry Pi Pico. I'll start with a personally embarrassing and annoyingly relevant story. I'll also tell you about a minor 'gotcha' when using SPI on the Pico, and how you can avoid it. Finally, I've include the code and fritzing diagram I used to test the interface. First, the story. Back in 2012, when the Raspberry Pi was fresh and new, I was running a startup called Quick2Wire.  We made add-on boards for the Pi. Just before Christmas we sent out our first batch of boards to a small army of beta-testers. The beta boards didn't work. Somehow a single trace on the pcb had got deleted and one of the GPIO pins was isolated. The boards were still usable and it wasn't too hard to solder in a jumper wire to replace the missing trace, but it was very embarrassing. It wasn't just that we'd shipped boards with a defect. The really annoying thing was that I'd set up an  automated loop-bac
Read more