week 18

• project development
  Assignment: complete your final project, traking your progress



what tasks have been completed and what tasks remain?

Since I changed my final project, in agreement with my tutors, 2 weeks ago, I started immediately to draw a plan for accomplishing all the requirements of the project. I selected first all the things to buy or find outside, as components and materials for the generator, in order to find or buy as fast as possible.

- Aluminum: I need a 5mm thick plate minimum size 21x25cm to generate the front plate and the central frame. Status: Done

- Cork: I bought easily a sheet of cork in a normal hardware shop, size 100x20x0,5. Status: Done - Peltier cell: this is the topic component because is what provide energy. It is to try to find a TEG and not a TEC with minimum 6 watts output. Status: To do. - Heatsink: As I designed the whole Generator to fit the standard 80x80 mm of computer desktop heatsink size, I’m searching in many old ones to find a good one. Status: Done

- Electronic components: As I’m going to create 2 boards (dc/dc converter and main controller board), I’m going to buy all components I don’t find in the Lab in a store in the city. Status: Done

- Screws: I don’t know yet if I’m going to use the fan which depend on the power of the Peltier cell I’ll find. If it is not going to be enough powerful, I have to cut off the fan from the project, the totla lenght of the body will be shorter so I bought a single 1 meter long screw-bar and cut it at last. Status: Done About The rest which is to be done in the Lab:

- Handle: This has to be printed as I have the measures of the 2 boards to put inside. Status: To do.

- Boards: The first one, the controller one has been done for allowing me to start writing the code. The dc/dc converter is yet to finish. Status: To do

- Arduino code: I’m writing a code for reading the 2 thermistor NTC 10k and set a logic relation with the buzzer. Status: Done.

For the dc/dc converter I have ready a sketch. Status: Done

Having bought Aluminum and cork, I’ve been cutting and milling them. Status:Done

Remaining to do: Dc/dc converter, find Peltier cell, print the Handle and make some test.



what has worked? what hasn’t?


I have had 2 problems:

- I’m going head without the fan option beacuse, according with my tutors, here in Spain is not possible or very expensive to inport a good Peltier cell from USA with this timing. The power generated will not allow the generator to sustain the load of the fan (more or less 2 watts).

- The dc/dc converter I tried to work on, found on Fab Lab older stuff, doesn’t work at all and there is no way to create in time something with a minimum of efficiency. Going well:

- The Modela has worked slowly but fine milling the aluminum for the front plate and the frame. - Cork has been cutted with laser quickly. Finding the setting has not been difficult. Just a little faster and at lower power compared to equal size wood cutting.

- I’ve founded the heatsink just as I prevented: being such a standard, I found may in the electronic “cemetery” we have in the back.
what question need to be resolved? - Peltier cell: I have to buy a cheap one which is also less resistant to high temperatures.

- dc/dc converter: As I have already designed a board for controlling the device sensors, I’m going to buy a commercial converter. It is cheap and it will let me go ahead with the project.




what will happen when?

While working on the project, as the only problem I am facing is about forniture, I’m sure that I want to improve with this generator even after the course.

I am sure this technology is growing fast and the prices of the TEG modules is slowly dropping. My application is simple and useful, it is to make it cheap, local and quite ecological.

So I’m going to create a more powerful version with more features as a double USB socket, a double output voltage channel to operate the fan and maybe I’ll provide it with a liquid cooling system.

A second step of improvements will be on materials.

Ceramics should fit perfect for dealing with high temperatures games. The goal would be 3D printing all the insulation compound and the frame in ceramic, with much more free forms when designing.




what have you learned?

I am used for my past experiences to be very organized. I use to make a plan starting from the end, the delivery. This way I can control better both the time for every task and the relation between a task and the other following a rigid coherency with the project. I this case I couldn’t. Organizing the job with so many people working on the same machines is very difficult.
Then I have to say that even if the tutors are always doing their best to help everybody, I have wasted a lot of time waiting for talking with them and get the infos or tips or basic instructions when needed.
Last, I can say that I’m learning to be more clear with file storing.