Ports and Adapters - Struggling back to Beginner's Mind

By -

I have to admit it: I've been struggling over the last two days. 

I'm working on a write-up of a Walking Skeleton for Lazydoro, together with sample code for its Ports and Adapters architecture.

I often create a Walking Skeleton at the start of an application. Lazydoro is now in its fifth version,  there's already a finished working version, and it's difficult to 'un-know' how it evolved. Trying to create what I might have written at the start has been quite a challenge

The process has been valuable, though. I think I understand Ports and Adapters better through working on my sample code and explanation, and it's had another benefit.

I've set up an automated deployment process which I'll be able to use for future MicroPython projects.

Automating deployment

Some applications can be deployed as a single file, but small modules are easier to read and test. lazydoro now consists of 9 files in a three-directory tree, and deploying a new version manually has become a real pain and is prone to error.

The new process uses a gist on GitHub which deletes all the files from a MicroPython-based board. It's always possible that your code relies on a file that you deployed a while back but have now forgotten about - a common cause of 'It works on My Machine'. 

Deployment to an empty file system is the safest way of avoiding that.

There's more to the deportment task than that, and I'm documenting the whole malarkey.

What's coming

I'm not sure how soon I'll have all the sample code ready, but you'll get to see three things:

  1. The automated deployment process
  2. The Walking Skeleton, and what you risk without one
  3. Ports and Adapters in an Embedded Application, and how that architecture helps with unexpected change.
Meanwhile I will be posting a short article about a simple technique for making stack-able breakout boards using strip-board. It's a very simple trick I forgot to apply to lazydoro until this morning; the buzzer break-out board now look much neater. 









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