johnsl/fsr_endstop

Force-Sensitive Resistor controller designed for Delta 3D printers for automatic bed leveling

fsr_endstop's Issues

toucher

another iteration of your idea:
https://github.com/random-builder/toucher
please let me know if you have any thoughts

Thermistor inputs to standard endstop inputs

You mentioned the following in your README file.
"Johann's original branch used one of the thermister inputs, but he later changed to using one of the standard endstop inputs"
Why did you do so?

Raw FSR values over SPI?

Hi. I'm working on an AI delta printer calibration fork of Smoothieware. It works really well so far, but only knowing the depth (not X and Y) limits accuracy. It has to assume the probe is hitting at the X and Y where it thinks it is, because it has no actual feedback other than depth.

I have a theory that FSRs might be used to triangulate the X and Y position being touched. I don't know if FSRs have enough accuracy or repeatability, but if they do, it would be great. I ordered one of your boards recently and I'd like to try to get it talking to a Smoothieboard controller over SPI. I know the processor supports that protocol. Do you think the processor is fast enough, and has enough RAM, to continuously stream the FSR values over SPI? I wouldn't have it maintain a running average or anything like that - just have it send numbers over the wire.

Use on a square Cartesian bed.

So far the best way I can figure to do this is using the 3 fsr pads under the bed using a maximum equilateral triangle solution or just inside the leveling screws one in each corner and one mid bed on the opposite edge...
It would be nice to be able to attach a 4th fsr and place them in each corner to reduce any possible cantilevered error due to areas probed outside a triangle within the square bed.

Is there a way to do this? Or should I just restrict the probe points to areas directly over the 3 sensors?

using the board with external 5v source

Hi,
I would like to use this board with an external 5v source, then somehow connect it to the 2 pins of the z probe input on my printer.
is that possible?

ps
I cant use 5v directly from the printer, thats why im asking
rgds
PB

Trigger debounce...

John -

Does it make sense to add a "trigger debounce" feature that will discard subsequent triggers if they happen very quickly after the first? I am thinking this could reduce false triggers?

Any thoughts or comments can also be directed to brad )at( ulti bots.com.

Thanks the great board and addition to the community - Brad

trinket version?

Hi

i saw WingTangWong 's trinket version of your code, but he removed the thresholds so i cant set them

of course he had to remove individual leds etc but the thresholds i cant figure why he removed

any chance you will make a trinket version?

False Triggering

I have four fsr's set up on a flat surface w/ a flat glass plate on top of them and I'm running 2 sets of 2 ea fsr connected in parallel or a total of 4 ea frs. The resistance I measured in the wires attached to the fsr's ranges from 160K to 240K ohms.

1. Do I need to lower the sensitivity of JohnSL board to prevent false triggers?
2. Can I add 500K ohm resistor in series with the fsr's to help prevent false triggers?

Please advise. Thank you.

Controller should detect bad/flakey FSR connection

After tracking down why my bed was never leveling quite right, I found one of my FSR sensors was damaged (small crack running across a surface wire on one sensor). It would sometimes make a connection, other times not. When the connection was broken, the FSR controller would not detect pressure and it would not give an error.

Is the controller sensitive enough to distinguish between an FSR with zero pressure (ie: MΩ resistance), and between no connection at all (ie: a damaged or disconnected sensor with infinite resistance)?