cool!

[jschoch]

This is great! Very cool. I'm playing with using velostat for a 3d probe and just found this. I have a

A few questions:

1. how sensitive is this?
2. strain gauges are cheap, did you do this to prove you could?
3. did you test the setup with a strain gauge?
4. did you try this with different resistor values?
5. Did you try this with plain old pcb traces to act as the strain gauges?

[IvDm]

Hi! Thank you for your interest in my project. I apologize for the delay in the answer: I just recently saw your message. I will try to answer your questions:

1.In this form, the sensitivity of the sensor is about 90 grams. During testing, it turned out that this is the optimal value for my 3D printer. Sensitivity can be changed by changing the values ​​in the sketch.

2.Yes, I just wanted to check if it works.)

3.Yes, I used strain gauges and everything worked perfectly.

4.With less resistance, the sensitivity becomes somewhat less. With greater resistance, the sensitivity becomes slightly larger, but the likelihood of false alarms from temperature fluctuations increases.

5.I checked, but I could not make very thin tracks. The minimum thickness of the track at the same time turned out to be 0.1mm. At the same time there is a high probability of obtaining poor-quality trails. With such tracks it works very badly. If you make the track longer, then everything should work well, but this will increase the size of the device.

[Harvie]

Did you try this with plain old pcb traces to act as the strain gauges?

I'd really like to get this working!

false alarms from temperature fluctuations

Well placing such device directly in neighborhood of 3D printer hot end does not sound very good :-)

[IvDm]

jschoch, a little off topic, but thanks for your recommendation of my project on the resource Hackday. I did not expect it to be published).

[thebrakshow]

Hey out of curiosity, why such a large resistor package, is this so that they flex more?

[IvDm]

Hi. On the contrary: the area of ​​the active conductive coating is larger, therefore, they can be bent less than, say, resistors of size 2010.