I just measured the sideways force on the x-carriage bearing (very unscientifically, using an elastic band and some known weights. I make it about 6.5N. So that force sensor I linked to should indeed be suitable for measuring the load on the x-bearing.by dc42 - Ormerod
If anyone is game for redesigning the x-carriage to (a) make the x-runner bearing mount adjustable, and (b) integrate a force sensing resistor to monitor the sideways load on the bearing, then I'll sort out the electronics and (if necessary) software. Just need to determine first whether the normal sideways load is within the 0.2N-20N range of that sensor, or else find a more sensitive sensor.by dc42 - Ormerod
Alternatively, how about a single sensor that monitors the force applied to the x-runner bearing? That would be usable all over the bed, and could also serve as a head crash warning.by dc42 - Ormerod
The existing output is just an analog reading. The least expensive one I found is this. Looking at the datasheet, you might get away with connecting the FSR between +3.3V and the Duet input, with a resistor of about 10 to 50K to ground, and a capacitor in parallel with the resistor to improve noise immunity. Multiple FSRs could be connected in parallel. But it would be better to use an attiny orby dc42 - Ormerod
You could have one force-sensitive resistor on each corner of the bed, then you could still do automatic bed compensation. Unlike the IR sensor, it wouldn't require any calibration because the software would only need to look for a change in resistance, not an absolute value.by dc42 - Ormerod
M503 tells you that the Duet can currently read config.g and shows you what is in it. It does that even if it failed to read and process config.g at startup. So try what I suggested. 9th pin from the right on the lower row is correct.by dc42 - Ormerod
Quoteiamburny I wonder if there is a thermal cutout for the hot-end and bed? Matt There is a software cutout, in that if the detected temperature goes above 300C then the corresponding heater is cut off. But the firmware does not yet use the watchdog timer, so there is no guarantee that the firmware remains running. The bed temperature will reach at most about 125C with the ATX power supply.by dc42 - Ormerod
How about making the bed from carbon fibre sheet like this? Does anyone know how rigid, temperature-stable, and heavy this is? Sadly the A4 sheets are slightly too small.by dc42 - Ormerod
My 4Gb Maplin card is MicroSDHC and cost £4.99 AFAIR.by dc42 - Ormerod
Your voltages are correct. Check the blue wire is connected to the correct Duet pin, However, I suspect that your Duet is not running config.g due to slow SD card. Try sending M558 P1 manually, and see if you start getting sensible readings after that.by dc42 - Ormerod
Quotekwikius Would a capacitive sensor be more accurate. You sure have a big aluminium plate as one plate? That's a thought! I think the IR sensor can be made stable, if it is lined up with the nozzle and modulation is added; but it will always have to be at one side of the nozzle and therefore sensitive to rotation about the y-axis. A cap sensor could be mounted on the hot end, with two platesby dc42 - Ormerod
Quotekwikius Could try reinforcing it with carbon tube or strip. I think this Carbon square tube on ebay would fit in the insulation layer in atriangle between each screw, glue with cyanoacrylate, and you could add a further one ( may need to be e.g 10 mm strip, but that might fit) under the mdf part along the y axis in front of the extrusion.. An interesting idea! I think the plywood centre rby dc42 - Ormerod
Quotepicnic My machine is telling me I have a fault on the sensor when I turn everything on. Having checked it out I'm not sure there is an error. FYI that means the Duet thinks the temperature is below -30C or above +300C. I know the extruder thermistor isn't accurate at low temperatures, but I think perhaps it's time to ask for a new one.by dc42 - Ormerod
Mark, I already have it set so that the USB ports don't get turned off when the computer sleeps. But I probably don't have that one set to wake up the computer.by dc42 - Ormerod
I'm finding the Z-height unstable, to the extent that getting the Z=0 nozzle height good enough to lay down the first layer needs manual adjustment each time. For example, when a print has completed, if I set run setbed.g (which homes all the axes, as well as doing bed compensation) and start another print, typically the head is too low and the extruder stutters because the head is dragging on thby dc42 - Ormerod
Paul, I had the same problem with the original card supplied with the kit (config.g not running, so Pronterface thinks the Duet is offline). I bought a Maplin 4Gb Class 10 card, and I have had no problems since I used that instead.by dc42 - Ormerod
Sounds just like the x-plate and x-rib that I received with the kit. RRP has now made the slots bigger to stop this happening.by dc42 - Ormerod
Last night I left a print running. When I came to it this morning, my computer had gone to sleep, the print had stalled not far from where I left it, and there was burnt plastic under and on the print head. I woke up the computer and the print restarted, but the extruder temperature was reading 303.4C. In fact the extruder was cold. Other than the burnt plastic on the nozzle, there seems to be noby dc42 - Ormerod
Simon, my sensor readings are still good enough to use. The lower readings will increase the sensitivity to ambient light, but I now have the Ormerod in a room with LED lighting, and the sun hasn't shone for several days. But I may print your original design anyway and use a high infill factor this time. And yes, I always leave the fan running until the extruder has cooled down.by dc42 - Ormerod
QuoteNumber 192 Did the additional 0.8mm improve your sensor reading? Unfortunately, it had the reverse effect. My sensor face (not edge of sensor board) was already 1.5mm above the nozzle, so when I calibrated at 1mm nozzle height, the sensor range was 2.5mm, which is ideal. Now it's nearer 3.5mm and my sensor readings are lower. Bear in mind that I had changed some component values so that I mby dc42 - Ormerod
kwicius, if you are getting stringy prints, what worked for me was increasing the retraction distance in the slic3r printer->extruder 1 settings to 4mm (default is 1mm AFAIR).by dc42 - Ormerod
picnic, would you care you try my modified firmware, posted at the start of this thread?by dc42 - Ormerod
The problem I had was with halogen lighting, although I found that bright sunlight caused problems too. I don't think fluorescent lighting would cause much of a problem, because unlike incandescent lighting, it doesn't produce a lot of IR.by dc42 - Ormerod
Hitting M503 in Pronterface (or Arduino serial monitor) gives you the contents of the config.g file, not the current settings. However, unless you have the problem that I and some others had (config.g not getting run because SD card supplied was too slow), then unless you have manually changed the settings since config.g was run, those should be the settings that the Duet is using.by dc42 - Ormerod
I've just found the answer to my own question. A comment in the firmware source says the extrusion thermistor is RS part # 198-961, which has a 10% tolerance and a B value of 3960. By my calculations, at 200C the 10% tolerance could result in a reading as low as 194.7 or as high as 206.0. So the tolerance is about +/- 5.5C at PLA printing temperatures.by dc42 - Ormerod
Rory, it's actually the product of RPM and pitch that matters (assuming constant blade diameter). The higher RPM fans from RS will have finer pitch to compensate, assuming they are designed to accelerate air from standstill just like the lower-speed ones. What this design needs for the second stage fan is higher RPM than the first stage but the same pitch, or same RPM and courser pitch. I think lby dc42 - Ormerod
I'm wondering what the tolerance of the 100K thermistor is, and hence how accurate the temperature readings are. Although an accurate temperature reading isn't essential, because you can find out by experiment what works well on a particular machine, it does make it difficult for people to compare results and swap settings. I'm now using 210C first first layer and 205C for the rest, but someone eby dc42 - Ormerod
QuoteRory166 Re 10mm fans, what about having two 10mm fans with 2 perhaps 3 of these static deflectors attached to make a higher pressure compressor. The idea of the 3rd one would be to catch the rotational element of the output and direct it forward. In that arrangement, the two fans should really have different pitch blades (the second with a courser pitch), or rotate at different speeds (theby dc42 - Ormerod
Quotedieterzar On my one it only worked once reset with the network cable plugged into it, if I plug it in after a reset, no go... It otherwise logs in fine and does everything fine via LAN. No issues. Dieter, is that with the standard firmware, or my modified version?by dc42 - Ormerod