I have a few things posted around online. My apologies for not linking them here earlier, as I kinda neglected this post after making it. Documentation site (under construction, still filling things out when I find time) The github has all of the schematics, Eagle source files, drawings, diagrams, and 3D Models I've made so far Gfycat of one of the alpha boards running on a Monoprice Delta Miby pyr0ball - General
Well there's been a lot of development since my last post. Got a rudimentary website up, as well as a documentation site, and I'm in the process of building and shipping out beta units for testers. I did some rough tests on my breadboard/oscilloscope last week and found that the trigger signal actuation takes about 21.5uS (microseconds) on average from the piezo input to signal output, so it's eby pyr0ball - General
Quotedc42 Quotepyr0ball I'm using a hardware interrupt, which is VERY fast (like on the order of a few microseconds). From what I understand about dc42's effector, it's using an adc input and software to analyze the signal, which requires the adc pin to be actively polled That's correct. But how fast does it need to be? We clock the ADC at 250kHz, giving a conversion time of 52us. We recommend pby pyr0ball - General
Just an FYI, I'll be hosting a livestream later next week explaining how the circuit works. I'll also be recording it and will upload to youtube/gfycat for later review. I'm also very much open to suggestions, or design inputs if you guys want to contribute. This is just the best way I know how to do what I wanted. If there's a better way, I'd be happy to incorporate it!by pyr0ball - General
Wow I need to check back in more often! Sorry for the delay in response. I'll do my best to respond to everyone QuotePippy I wonder what it is you're trying to do with the outputs of U3C and U3D (see attached image) ? Looks like you're trying to combine the outputs but very unsuccessfully. The output of U3D will have no effect (depending on the value of R4). The voltage follower in this partby pyr0ball - General
Quotefrankvdh I'd be keen to be a beta tester. One question: is this suitable for under-bed mounting? I'd rather mount under my delta's bed than hang it, and the associated wiring, on the effector. Although the FFC sounds great too! I did see you ask over on the discord, but I wanted to respond here as well. Yes the standalone version of this sensor would be suitable for under-bed mounted piezby pyr0ball - General
Yes, all of the documentation* is available on the GitHub under docs: *Finished documentation. I'm still working on fleshing it outby pyr0ball - General
Hi there! I recently published a project I’ve been working on for nearly two years, with the aim of solving the biggest issue facing cheap hobbyist 3D Printers: How to get a perfect first layer on any printer, using any type of hotend, and any print surface, even swap-able ones. While this isn’t the first Piezoelectric z-sensor that’s been brought to the 3D Printing community, it is the first tby pyr0ball - General
@dc42 Well the current code I'm using handles dc drift very well. I'm currently building a new branch of my project utilising an R-2R ladder. It should give me 16 values rather than the 5 I started with, so thanks for that tip! I'll see if I have any other spare I/O I might be able to use to get higher resolution out of it. Before I go that route I'm gonna try setting up a pwm dac and see howby pyr0ball - General
Quotedc42 Done properly, it's not slow enough to matter. Using a probing speed of 20mm/sec (which is quite fast), if the code takes 100us to take an ADC reading and do the calculations, the jitter introduced would only be 2um. Hey I just realized I recognized your username from the thread over on soliforum for porting Repetier/RRFW over to the DaVinci Jr. Small world! Anyhow, I've got a GitHubby pyr0ball - General
QuoteMKSA What I thought as for the intended mode of operation but: - Based on the schematic, the 3X amp as drawn is wrong, its IN- is connected to ground ! Schematic error ? - The 2.5V Vref with a 1M will have no real effect as it is connect to the Opamp OUT. I can't see how it could: "so you don't end up with a mess of extremely fast signals all coming through.". So , is the schematic correby pyr0ball - General
@Moriquendi If you'd prefer something else, that's fine too, but I know discord has screen share capabilities along with voice chat which makes things easier As to your oscilloscope loading the piezo output, that's cus the probe doesn't have as high an impedance as an amp, and the output current of the piezo is tiny so it just gets vdrooped to nothing when probed in-circuit directly. This behaby pyr0ball - General
QuoteMoriquendi @Pyroball, It looks very interesting, can you give an explanation of how it works? Specifically how the software and hardware interact? Idris See my reply above for an explanation of the electrical characteristics, but it should essentially work as a drop-in replacement for the Precision Piezo version, just with better filtering and self-calibration (no more fiddling with 3mm pby pyr0ball - General
QuoteMKSA Looking at your schematic, I found it quite strange although I understand the principle. A 3X Opamp for the piezo signal, its Vout fed to a comparator whose triggering level is determined by a R ladder adjusted by the microcontroller. Now, the front end Opamp is "strange", and why is its output connected to a 2.5 Vref via a 1M resistor ? Regarding the R ladder. How many possible valuby pyr0ball - General
Hey guys, I just published my mostly complete electrical design that incorporates an onboard microcontroller for auto-calibration, and an optional version that converts the extruder cablechain into an FFC. Github Thingiverseby pyr0ball - General
QuoteCaptainHero So while i am still trying to Frankenstein my way to a somewhat working hotend mount on my Wanhao I3 i made some progress recently which made me hopefull that there is light at the end of the tunnel however there are a few issues which i can't seem to pinpoint why they keep happening seemingly randomly. So i have made a contraption to have a single piezo being triggered around mby pyr0ball - General
I made a universal mount for the PZ20 board for use with pretty much all Prusa i3 and clones. Initial testing looks good so far.by pyr0ball - General
Yep, I referenced their design when I was building the smaller of the two stepper switcher boards. I've also added a new one: An FFC breakout board with integrated Precision Piezo circuitby pyr0ball - General
The point of the repository, in contrast to the wiki, is meant to have a higher level of collaboration with specific feedback and issues tracking. It's not exactly easy to go look through it wiki's revision history to find a specific change, and then assign an issue to it like you can with github. The other thing I see as better about the github is that I can push minute changes quickly, get feedby pyr0ball - General
I'm aware of that, however the wiki doesn't track changes, issues, or experimental designs the way this repository would. I intend this repo to be an open forum for designers and developers to put forth ideas and get feedback. The wiki is a reference, not really an appropriate place for that IMHO. edit: I decided to get started on it, so here it is:by pyr0ball - General
I've been tinkering with various little PCB designs for my own custom printer, and recently started helping out with the Marlin firmware folks in reverse engineering the Prusa Multimaterial boards. I wanted to know if there already is an open source hardware repository that I could contribute to, or if I should start one. I was thinking of starting a github and uploading the cad files along withby pyr0ball - General
Quoteobewan The main problem with using themocouples is that they output such small voltages( mV) this voltage is susceptable to interference from the stepper motors and allso the PID used to heat the hot end. Well luckily I work in a building with a bunch of electrical engineers and I picked up a thing or two from them. All I had to do was add a small capacitor (100uF) from signal to ground anby pyr0ball - RAMPS Electronics
Well apart from the thermocouple instability, I got it working!!!! I had to adjust some temperature offsets and such, but I got it printing!by pyr0ball - RAMPS Electronics
OK well I'm running into more trouble with that darn thermocouple. It seems to be getting some phantom power from elsewhere on the board because when I use the extruder stepper, the voltage instantly drops by about 10mV, causing the temperature readings to drop which makes things difficult. Any ideas?by pyr0ball - RAMPS Electronics
OK got new thermocouples in, also found this lovely post that gave me an idea as to what voltages the amplifier should be putting out based on temperature. It looks like the amp is putting out about 10x the voltage stated in that thread (room temp is coming in at +2.8v) so I tried turning the gain on the amp down, but I'm still getting a MAXTEMP error and the system halts. This is with thermal prby pyr0ball - RAMPS Electronics
Moar updaet! Currently working out kinks with the thermocouple amp. Switching to AD597 for now just for simplicity. I get *some* readings off of the ad597 (variance of about 0.1 - 0.6°), so I adjusted the offset up 23° to make it about ambient temperatures. As soon as I turn on the hotend, however, I get a "MINTEMP" error either immediately, or after a few seconds depending on the gain settingsby pyr0ball - RAMPS Electronics
From what I've read, thermristors arent as accurate as thermocouples and can't handle as high of temperatures. Also figuring difficult things out is more fun! If I can get this all working then I could build a decent conversion guide for other people who might want to get off the badly designed Mightyboard.by pyr0ball - RAMPS Electronics
UPDATE: HBP thermals have been fixed! I had to re-add the pullup resistor on the RAMPS board, and remove the one on the bottom of the bed itself, and now I'm getting good temps off of it. Also the heater itself is working so that's awesome. One thing I do need to check on is the accuracy or compensation I'll need to use because of the aluminum plate on top of the HBP probably is dissipating moreby pyr0ball - RAMPS Electronics
OK Got the triggers fixed and the steppers can now move in both directions, so that's good! Also ended up fixing an orientation issue I was having with my Y and Z axis at the same time so that's good. I managed to dig up an AD597 and get one of the thermocouples hooked up with that, and just for the sake of debugging, I disabled the minimum temperature for the HPB using -1 and set it up as a "1"by pyr0ball - RAMPS Electronics
QuoteDust 1) check you endstops status with M119 comand. when endstops are triggred you cant move -ve 2) as a guess I would say z max feed rate is probably to high Looks like you're spot on with that one! All three are showing as triggered at the moment. Trying with endstop logic inverted now. How/where would I go about adjusting the max feed rate for the z-stepper?by pyr0ball - RAMPS Electronics