Tuesday, October 10, 2017

5V Solar Power Supply - testing system

In order to test the solar power supply without connecting the Raspberry (also because used to monitor the solar charger itself), here how I'm proceding.

First of all we need a way to simulate the Raspberry Pi "load" toward the system.
Browsing around the net I found the perfect tool for that, an USB load capable to be set to draw from few mA up to 3A.
I did buy it from Amazon.
Another nice thing to have is an USB voltmeter/current meter like this one :
It is handy to have the voltmeter connected to the load in order to regulate the load to draw the average current used by the Raspberry Pi, around 350 mA.

Then the idea is to use the Raspberry Pi itself, powered externally, to run a monitor program to capture the battery charge/discharge and other conditions, like full sun/night to determine the solar power supply under different conditions.

Block schematic

Here a block schematic about the test environment.

The goal is to have the system set to draw about 300-350 mA from the solar power, simulating the average load of a Raspberry Pi, and see how the system behave in few week run, monitoring the battery charge/discharge via the Raspberry Pi.


As mentioned, the monitoring is done using a Raspberry Pi with the groove system.
At least we need to monitor the battery charge and the amount of light (used to determine if there is sun enough to charge the battery.
The monitoring program, in python, running on the Raspberry Pi is quite simple.
It just open a log file and every 60 seconds reads the value of the voltage and the value of the light.
The data collected in a file  are then displayed on a graph using  gnuplot.

Sunday, September 10, 2017

Working on Teirmilab

Here a step-by-step guide to work on git for the TeirmiLab project.
If you are new on git and github, read this article first

TheTeirmiLab project is on github, so if somebody wants to join it, or just follow the progress, can clone the git repo for Teirmilab.

Let start from the link for the TeirmiLab github :

Note that you have to ask to be added as collaborator if you want to use this repo.
Currently is private, not yet public.

Clone TeirmiLab

Use git to clone the TeirmiLab project, with the command :

  • git clone
That's it !
On your directory, will exist a directory called TeirmiLab, containing the code.

Update TeirmiLab

Now that you have TeirmiLab on your machine, to keep it updated is even easier.
Simply go in the TeirmiLab directory and issue the command : git pull

  • cd ~/SteveProjects/TeirmiLab
  • git pull
That's it !  If the code on the github is changed, it will be updated on your machine

Working on TeirmiLab

Commit TeirmiLab

If you want to collaborate to TeirmiLab, you can modify the code on your machine, and keep track of the modifications locally, using git.
Issuing the command git status returns the status of the modifications made to the code.

Every time you modify a file, git status will indicate a modification.
Every time you will have to add it with:

git add file_name

git add * will add all the modified files.

Then it will be possible to commit the file with:

git commit file_name

All these operations are LOCAL to your machine !

If you are a registered collaborator to the TeirmiLab project, then you should be able to "push" your modifications in the github:

git push

Friday, May 12, 2017


Just a brief note for spammers.

Often I receive some comments on some articles of this blog.
Many of them are clearly just spam masked as comment.
I have zero tolerance for spam comments, as soon as I identify one I'm deleting it (if already published) or I can prevent the publication if I recognize it.
On this blog comments must be approved by me, they are NOT automatically published.

So, who wants to post spam here, will have hard time and my total contempt.
Don't bother to post spam.