a little update to say that we manage to drive our coding wheels by switching from the comparator of the STM32 to the simple ADC and handling this part with software.
here it is some so much more precise results
Hi everyone, this is a soft week for breathup, indeed alexandre is a little bit stucked on the ads driver so we must wait until he make it work.
Most of our job is yet integrated and work fine on our PCB like the LoRa, the bluetooth, the sd card, the FatFS, the filters, the qualification, the RTC and the IMU. Thus we need to fix little details like the coding colors of our leds, and how to use our buzzer but Benoit already implements something. After that and with the ads working, our project will be over !
During the beginning of the week, I helped Alexandre fixing some bugs on the ads driver but now I can’t help him anymore because I never read the ads datasheet and he will waste too much time explaining me. Thus, I’m cleaning out our code and I’m writing our integrated final code for acquisition routine.
Hope, we will soon acquire something ! Stay tuned !
Benjamin for BreathUp
Such important improvements this week, I resolved my writing problem ! In fact there were not any problems at all, I was writing but It just took so much time… So I decided to reduce the number of writing and increase the length of what was writing. It speeded up the task from 10 minutes down to 30 seconds.
Thus, I ended with implementing the filters on our PCB, it worked fine ! I tested it and compared with what we obtained on the computer: exactly the same. I didn’t try to determine filters speed, but it was enough faster to appear immediate. But this tests need to be perform so I will try to do it during the next ultimate week.
After that, I decided to integrate the whole code and with Xavier, we realized that both LoRa and SD card couldn’t work at the same time, we supposed that it was because of some DMA’s channel… So that Xavier and Samuel wrote a new SPI driver without DMA and now LoRa and SD card can both worked together again !
I also integrated, with Xavier, his job on qualification, we tested it and we had the same results as on the computer too.
Eventually, I worked with Xavier to weld our electrode connectors and we helped Alexandre to merge his work on the ADC with what we have done recently. We performed some tests: we are able to read the ADC output but we can’t read as fast as the ADC write and also, we don’t manage well the data. We always read zeros.. So we have one week to deal with that and to fix some details: it seems that the project will be done soon!
Stay tuned during the last week !
As you could read on the post of my teammates, we saw Laurent this weekend to show him our works on the project about the acquisition part and the algorithms. During is meeting, Laurent confirmed us that after the digital filters we had a good Electromyography (EMG). That is a very good new.
After that, with Alexandre, we made some tests to check if we could use an unipolar supply power and if the ADC internal clock could be used to make measurements. We could see a good acquisition but to be sure of that we need to make others tests and treat them this the digital filters. After an other reading of the ADC and acquisition boards datasheets, I identified the different signals and bit registers to modify. But there is a signal (the clock select signal) that on the testing software it is not possible to choose the value of that. I think its value is 1 by default because there is a jumper on the board to choose this signal as the input on the ADC or to put this input on the ground. However, I did not find something witch confirm my idea.
I also made a little review of the analog part of the schematic.
For the next week, I don’t know if Alexandre will work alone on that tests or if I will help him. I will finish the analog schematic section just after the confirmation of the analog supply power and the oscillator. I anticipated the two cases. So,I will just need to make some little modifications. I will begin to work an the smartphone application too.
That is all for today,
Have a nice week.
Benoît for BreathUp.
During the last 3 days, I could not work a lot. Indeed, I made some tests about the oscillator on the testing board. To make that tests, I need to use my Windows Virtual Machine but I don’t know why, the board connects its to the Windows machine and disconnects. So I can’t use the board’s software. However, the board does not sometime unplug and I can make some tests. I tests different configurations thanks to some jumpers. I tried to use the internal clock of the ADC but when I disabled the extern oscillator, the acquisitions did not work. If my computer will allow me to use the software, I am going to make some tests to know if the ADC need a bipolar or an unipolar supply power.
I reviewed the analog part of the schematics too. And, after the tests, I will see it again.
Benoît for BreathUp
In this end of week, the result of our work is not so impressive compare to what we said in the previous post. Let start with the goal I settled in the last post. The first point was: “reduce the number of electrodes from 4 to 3” and the second was: “get an EMG”. On the first point, I study with our teacher Alexis the usefulness of the RLD electrode (which is right leg driven electrode). After a while we deduce that we couldn’t afford to use the system without RLD. Concerning the usefulness of the three other electrodes I will see it directly with Laurent, when I will try to get a true EMG with him on Wednesday (if he can come). To conclude I would say that my goal for Wednesday are quite the same they were for today.
Concerning the other guys of the group, Benoit and Xavier have done a pretty nice work on the PCB and the components. We almost finish it, I have just to do a small test on the acquisition card, to see if they can simplify a little the PCB.
About the algorithm, compare to the acquisition, it is quite the same problem. It seems normal because both are linked. This is the reason why, Benjamin will try to improve it on Wednesday.
I hope Laurent will come on Wednesday.
During the end of the week, I knew lots of emotions. Indeed, Friday, after some tests with lots of noise, I was lost and I did not understand why there was that noise. So, I took the user guide of the tests board and I checked all the default parameters to know if the configuration of the software was wrong or not. After that, I debated with Alexandre to find the reason of this noise but we did not find. With Samuel and Alexis, we tried to watch an electrode signal on an oscilloscope but we watched a noise of 50 Hz too. Alexis or Samuel, I did not remember, tell me to put a square signal in input of the board. So, Saturday, I put a square wave on the board and I watch the wave but there was a noise of 50 Hz again. At that moment, I thought we did never find a solution for that noise.
However, with my team-mates, we met Laurent. He brought us the cable for the electrodes. And with it, he showed us how make an ECG measurement. Laurent said us that we could watch EGC’s picks on the signal. But there were lots of noise. During a debate with Laurent and Alexandre, Alexandre had the idea that the power supply of the board could generate the noise. Indeed, in the user guide, there was a topic which said a supply with stack could reduce the noise. That is why I went to the robotic club to ask them if they had a pin and a box for stacks. Thanks to Telecom Robotics, we could have a new supply with stacks. We also discovered if the computer, which make the acquisition, was in charge there are a 50 Hz noise too. After, that problem was resolved, with Alexandre, we make some tests to have a good ECG with all the electrodes. I assisted Alexandre to reduce the number of electrodes used to have an ECG.
My main task is still to have an EMG (electromyography) to valid the ADC. This EMG will be valided by Laurent.
As I have already told in an old post, today, we have a the PSSC for this task. So we does not respect it and we are in late. I hope to valid this PSSC in the next days.
For today the group was supposed to validate the ADC choice for the EMG, and succeed in using the algorithm given by the startup we are working with. Unfortunately it will not be done for tonight.
However like I said in my previous post, step by step we are going forward! With Benoit and with the help of Laurent we had seen that 50Hz noise was there every time, even on a signal of a wave generator (idea of our instructors). At this moment I knew what the main issue was: The only fact to plug our acquisition card on the 50Hz is killing the EMG signal. Even worth, when the computer is no longer working on the battery, the noise is going throw the usb cable. It’s mean none thing: my working time is as long as my battery charge :). (By the way, my hearth is working very well, I am alive!) Then we start to reduce the number of electrodes, it was working quite well, until the moment the battery of my computer was over.
What’s more the algorithm given by I-respi is not as operational as they pretended. Benjamin and Xavier improved it, but not enough. Like Benoit and me, they should finish it by the next two days, and test it on the acquisition we will have done.
The main goal for now it is having the result we hoped for today with the ADC in the next two days. Hopefully I think the next thing we had planned, should not be impacted al lot (like the components choice and the drawing pcb, which is by the way something we had just done in class by Friday)
See you on Wednesday, and I hope I’ll give you great news!
After reading datasheets, with electrodes and some welds, with Alexandre, we made our first tests on ourselves and it was a fail. This tests was made with a testing board to understand how work the ADC. This ADC is specific for a ECG treatment. To make the EGC with our device, three electrodes are used: two for measurements (channels) and another for the ground. However, the ADC which is used needs three signals to create after a kind of average, a new signal of reference. This signal allows to reduce the noise on the channel to have a better ECG. So we need to find solution to have a good ECG without this signal.
Moreover, our first deadlines will be the next week. So, the next week, I am going to work on the ADC again and analogue filters. With my teammates, we will have lots of works during the next week.
See you next week!