Sensing Baby Kicks

Interesting sensor challenge.

Assuming the kicks generate a different spectrum of accelerations than a movement, perhaps an accelerometer or microphone would provide an easier signal to analyze. (Low-cost Piezo sensors generally have a resonant frequency that make spectral analysis difficult)

Another method might be to use a different sensor to detect when mother is moving and ignore the kick sensor at these times. This sensor would be mounted closer to her muscles and further from the baby. It could even use EMG sensors (electromyography).

Doug

Wow, that's a tough one. I'd almost think you'd need to pick up subsonic sounds and use DSP to recognise relevant signals. But I wouldn't be able to do that myself .

Maybe a broad belly belt of wearable conductive/resistive cloth where you can measure sudden changes in resistance when the little foot hits the belly?

Interesting theories. Dough 's solution will need too much tweaking but will be a better one in the long run.

Jan's solution has one issue- the cloth worn tightly will be uncomfortable over time.

But I'm getting good ideas. More inputs please.

In my defence, I'm going to suggest to buy stretching resistive cloth

http://openmaterials.org/materials-101-electrotextiles/

Electrolycra from Mindsets: looks and feels like ordinary lycra but it’s highly conductive. Its conductivity in one direction depends on how tightly it is stretched – if you pull it the resistance increases and then drops again when stretched even tighter. When cut into a thin strip, the material also warms up when current is passed through it and can thus provide the basis of a heated garment. A 6V battery will cause an appreciable warming effect. Resistivity: 5 ohms per 100mm, increasing to 20 ohms when stretched to 150mm. If the material is turned through 90º and stretched the resistance drops to 2.5 ohms

jancumps wrote:

 

In my defence, I'm going to suggest to buy stretching resistive cloth

And you could let mom remove and re-apply it every day to her own comfort, then press a callibrate button, and start measuring deltas.

The movement caused by the breathing of mom can be filtered out because that happens in a known frequency spectrum, much slower than the kicks and punches of little baby Singh.

Needs to be switched off when mama has hiccups and during morning sickness bursts

I have sought out some stretch sensor wires and will be trying them out. The rest of your hypothesis will take some time to test out and I will update as and when.

I am also going to continue experimenting with the piezo sensor and might try some surgical tape for temporary adhesion. There seems to be no solution currently available for a comfortable wearable...

Were you able to figure this out? Sure would love to give it a try!

I would develop something like this is my wife was pregnant - maybe play some music as feedback for the baby. I have developed a soft belt with sensors that could be used for this. It was developed for physiotherapy applications, but it would easily sense and discriminate a baby kick.

Hi Douglas,

I love the music idea. Could you share it with me? I have a lot of time on my hands right now. LOL