The previous week has been spent on figuring out the gameplay for the respiratory sensor and trying to incorporate the pulse sensor into the device.
One of the problems is that the heartrate sensor and the chest strap for measuring breath have to be located in a similar position to give good readings. We tested different positions of the sensors – and found at that right now the respiratory sensor is more exposed to noise – so that needs to be positioned over the heart rate sensor (at a more optimal position). Another concern is that people don’t want to wear this device on the skin. We are currently attempting to make the device so that the heart rate monitor can be taken out – and people can use the respiratory sensor on top of their shirt. This seems to work a lot better and make it more comfortable for people to wear the device.
This is what the first prototype looked like. However we found out that the pulsesensor didnt have good contact with the body – therefore we changed it into this other design (which is also easier for the user to put on as we replaced the connection of the strap with velcro.)
So right now the stretch conductive fabric is located on top of the heart rate monitor located at the bottom of the device.
We got the pulssensor to work and incorporated the heartrate into our sketch. But I wasn’t happy with the reading as it seems to skip some beats and act noisy. I don’t know if this is due to the position of the heart rate monitor or whether I need some more code to sort it out (Tom told me that it was probably due to the delay function in my code, and that I should try to replace it with interrupt instead) So I’m going to give that a try.
Although it works to some degree I do have some doubts about the polar sensor at this point. It’s uncomfortable for people to wear (since it has to be in contact with the skin) – Physically its difficult for us to put into the device and at the same time make it reliable for everyone. I will keep working on it – but I only want to use it if I think it will work and be reliable.
Here’s a test of both measures combined – however this is before putting them into the fabric which is causing some problems:
Another thing being illustrated in this video is some of the tests we did with our respiratory function. We tested the moving average function that we have gone over in class and combined it with the average function we were already using in our sketch. It worked really well and got rid of a lot of the noise we had in our readings. The downside was (as you can see in the video) that the visual feedback looked more manipulated. And from testing different users we found that people liked our original code better (which I found frustrating). Before the final we will do a few more tests to decide which type of data visualization/manipulation we want to go with.
We also agreed on a way to present our presentation. Our idea is to give people some time to visualize and see the autonomous physical mechanisms that we often take for granted. Like respiration and heartbeat(! if it works). After that we want to let people know that even though these functions are autonomous we are still in full control – which we want to illustrate using a game. We discussed the game and how to use it.
So far our game had been to difficult and made people dizzy. We agreed to set up some different stages – and in between give people some rest. Our thoughts are for people to follow a pattern created by circles. It will start easy and increase in difficulty over time. We also decided to make it a short game (1 – 1.30 min).
After incorporating this – this is what our sketch looks like:
This week leading to our final we will see if we can get the heartRate sensor to work reliably. If not we may sacrifice it for now – or have it as an option.
Also, we need to fix the wires going from the feather board to the bluetooth sensor and the alligator clips on the stretch fabric. The wires keep snapping above the connection to the board. This happened during the playtest and I have been trying to fix it again and again without luck.
I will try to make a casing for it, as that may relieve some of the pulling that happens to the wires. Also We would like to have a visual on/off light on the outside of the device. Which should be possible if we get the cables “cleaned up”.