First total test

Tuesday was it a big day. The first version of the software was finished so we could test is with the hardware. But this was in a open classroom. But it works very well. 
The software is written in C++ because we started of an example, this was the easiest and quickest way. Joeri did well research in this stadium, because we had no C++ experience.

 

In the movie you can see a fan and a led. In the future will the led be replaced by a bigger lamp. But the led is an indication for the heating element.

When we start up the software we need to push on 'Start' and wait 5 seconds.

This is that we can measure already the temperature and than is the measured value
more correct. The lm35 needs some time to be at the correct value.

When this is done, you can see the measured temperature by the lm35.
And you can give in the temperature you want.
In our test, it was about 23°C in the classroom. So we set that we want a temperature
of 22.8°C.
Than will the fan power on and cool the lm35. When the temperature is below 22.8°C, the led turns on, because it was warmer in the class, the lm35 warms up etc, etc ...

Problems with software PIC

It is quiet here because we are trying to adapt the code of the software of the PIC.
But it is very hard for us, the code is written in C++, and we can't program that...

Hopefully we can tell you soon that we make progress with the code.

Testing with V-USB and AVR

The last days/week we were very busy with testing with V-USB and AVR.
We based us on the Powerswitch example:
http://www.obdev.at/products/vusb/powerswitch.html 

And this is our first prototype pcb:

But like you can see, it was very fast soldered with the result that it doesn't work.

So the next prototype need to build:

This time, the pcb works! So We have tested the powerswitch with the commandline software. And this was succesfull.

But afther this, we want to make a graphical software...
First we had a problem with the .dll. After this was fixed we saw that it is

on this moment impossible for us to let this work...

So probably we go use the PIC18F4550.

Our Own USB Interface

Today we have tested with the USB Data Acquisition Card of Elektor (click).
Our previous students, 2 years ago have made this PCB with the application
Ball and Beam. And the PCB was still at school.

After installing the drivers, we had a error while opening the demo software.
The problem was solved if we open the software as admin.

When this problem was solved, the PCB doesn't work anymore,
our previous students made a PCB with copper tracks with the thickness of a hair I think.
Soldering a wire and the problem was solved.
After that, we measured al the digital I/O and analog I/O.

This evening , we finished (hopefully) the list with components.
Tomorrow we hope to search how the Demo software works,
and made ourself Demo software.

A lot of progress - Prototype

Here we are after a while...
But we were very active...

First, we have coupled all the small circuits to each other to check if it is working.
This worked, but is was on breadbord.
So the next step we have done was drawing the schematic, where everthing is on it.
Al the foregoing circuits that we have maked, were small schematics.

The next step we have done, was build this circuit on a perfboard. This is also the prototype of the PWM. And the power supply is the power supply that we are going to use in the future for the project... (Adapters).

The bad quality is because it is filmed with my gsm.
While we have done those test etc, we have make a list with components.
This is almost ready, than can we give it to the school to order.

Schematic of hardware

This is a small visualization about how the klimabox probably goes look at.

Negative Supply voltage

Because we are going use the Adapters that are available in the laboratory we have only a positive voltage. For our project, the adapter needs to set to 12V.
But for the op-amps that we are using, we need a negatieve voltage of -12V.
We found a very simple circuit with a NE555. We builded it yesterday quickly and it works fine. We measured an output voltage of -11,62V. And the input voltage was 12,6V.
This is the circuit:

http://www.circuitsonline.net/schakelingen/139/voedingen/negatieve-spanning-met-ne555.html