Team TAHMO

It took some time to get used to the logic of Git and GitHub but now it definitely feels liberating not having to worry about version controls and consistently naming different versions. All files developed for this project are from now on available through GitHub through the Team_TAHMO repository. A descriptive page with clickable links can be found on the corresponding Team_TAHMO GitHub Wiki.

We are getting there, hopefully making major follow-up strides over the weekend. Most design files are there:

• Schematic
• Gerber files used for the PCB production
• Fritzing file
• PCB image

The parts file is in this Google sheet.

Next steps:

• Finalizing code
• Parts placement
• Final test
• Finish Youtube movie

Here is the first design of the PCB, adjusted after discussion on the Hacker Channel this morning, for which many thanks, and studying the guidelines for PCB design https://hackaday.io/project/6936-pcb-design-guidelines.

Considerations:

- No surface mount (too little experience)

- Three functional groups: power supply (left), CPU (center), and RF part (Thunder click) as far from the rest as possible (it will actually stick out over the board with its RF part).

- Made supply lines wider

- Removed straight angles and replaced them with 45 degrees

- Hi frequency ground (crystal and GND of CPU) is isolated from the rest of the ground; only connected at one point to rest of GND

Unfortunately, with apologies to Yann Guidon, we do use the bottom side as well. You are probably right that it can be avoided but that will be the next version... Fortunately, at OSH Park, the price for two-sided is the same as for one-sided (about $10 per PCB).

Next steps, put all material on Github and order PCB and parts....

With the winning of the business competition in Rwanda, the building of the lightning detector becomes a serious pursuit. We decided on the following selection criteria for the materials, basically based on the idea that we are not professional PCB designers:

- Avoid surface mount (perhaps a next version?)

- Use pre-built modules for the RF components: AS3935 lightning detector and GPS module. There are well designed pcb's on the market that would be hard to beat.

We will build the PCB to house power supply and CPU and allows for solid mounting or connecting the GPS and AS3935 boards. The power supply will be solar panel based. Most of the time, the module will be asleep, during which about 70 muA is used. Once lightning is detected, the AS#(#% will produce an interrupt to wake up the ystem during which the system needs about 50 mA. We assume thunder storms will not last more than 24 hours, in which case the batteries chosen here should work.

With these consideration, these are the materials chosen:

Next step the PCB design.

Team TAHMO member, Gilbert Mwangi, participated this week (13-17 July 2015) in a business development workshop in Rwanda. The idea included the lightning sensor used in this Hackaday project. Fourteen partcipants, divided over five teams, developed their business models for innovation involving water & it (http://viawater.nl/en/the-library/articles-and-reports/wanted-rwandan-water-ict-professionals).

The business idea is to use the lightning sensor, together with regular weather stations and numerical weather predictions, to build an extreme weather early warning system for Musanze, an important tourist town in northern Rwanda. The idea won the first prize, consisting of $2000 for further market research.

Attended the HACKADAY PRIZE WORLDWIDE: SAN FRANCISCO event on Saturday 2015 to get a good start on the design of the PCB. Actual design will follow later this week.