23.-29.9.

In the past week we met with Sonja and Gerardo to test the ADS1292 on the adapter constructed previously. We assembled a test circuit from TI and connected 1.5V-3V to the input (variated by a voltage divider done by resistors and a potentiometer). We measured the output with an oscilloscope, but failed to get any rational output signal and called it a day.

Circuit on the protoboard with power sources of 1.8V and 3V 

The next time we met, we tested the ready circuit for an expected gain of ~15.56 dB(?), but looking at the multiplexer configuration of the ADS, it seemed that the switch config had to be programmed separetely, to be able to get the desired gain. No reasonable output was seen.

Later, I managed to finish the µcontroller adapter. I soldered the MSP430 QFN-package by hand and ended up with a fairly good result. The connections seem good according to multimeter measurements, but further testing will show if the chip overheated. This I doubt, because I soldered each pin heating them for only ~2 seconds. Here are some pictures of the final outcome:

Magnified from the previous image.

Finally we met Robert we had meeting on 16 September we discuss about the progress in the project and saw different circuits made by our group members me and Robert then agreed on the time for the meeting about wireless interface and then we had meeting about wireless interface on 18th September and Robert gave me some tasks now we have to work on the wireless interface part more as it is lagging behind.

2.-8.9. and 9.-15.9.

During the past two weeks we have had two microcontroller workshops prepared by Robert and Gerardo. We have learnt this far the very basics of microcontrollers and seen blinking light demos. 

Johannes soldered ADSs onto the PCBs etched previously. He also took photos of the PCBs with and without the components. Some of the photos are shown below. In addition, Usman created a bluetooth connection between two development boards.

Successful and unsuccessful PCBs:

                                          Photo: Johannes Pirhonen

                                          Photo: Johannes Pirhonen  

                                          Photo: Johannes Pirhonen

                                          Photo: Johannes Pirhonen

                                          Photo: Johannes Pirhonen

                                          Photo: Johannes Pirhonen

The first attempt of soldering the ADS onto the PCB failed. There was too much solder and the component also got overheated in the process.

                                         Photo: Johannes Pirhonen

                                         Photo: Johannes Pirhonen

The second try was the charm!

                                          Photo: Johannes Pirhonen

                                          Photo: Johannes Pirhonen

Week 26.08.- 02.09.

We have advanced to the stage that the first prototype construction is approaching. This week Johannes etched the before designed adapters at the University and he will drill the holes soon. These adapters are used for the ICs to connect them to the prototyping board for easy connectivity.

This week Sonja was busy with other studies, hence we have not advanced more in the power source design but she will send the suggestion list for the rest of the team to revise possible new power source chips after realizing that the voltage level was not sufficient to supply both the Analog front end and the Microcontroller (2,7V to 3,6 V).

Meanwhile Robert and Gerardo have started to prepare the first Microcontroller workshop taking place next wednesday...