My little electronics project over Chrismas and New Year [github.com] I'm just going to drop this here and ask what you guys and girls think https://reprap.org/forum/read.php?181,880687,880687#msg-880687 Wed, 10 Jun 2026 06:03:17 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?181,880687,881110#msg-881110 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881110#msg-881110 rq3 Next Wave Electronics Working Group Sun, 31 Jan 2021 13:53:45 -0500 https://reprap.org/forum/read.php?181,880687,881087#msg-881087 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881087#msg-881087 reprap.org]

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Mike]]> leadinglights Next Wave Electronics Working Group Sat, 30 Jan 2021 16:16:27 -0500 https://reprap.org/forum/read.php?181,880687,881082#msg-881082 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881082#msg-881082
Quote
leadinglights
Quote
majic79
.................................................................................. For probing, you could sync the query over the serial bus before stepping - might slow things down a bit, but that seems an acceptable price to pay.

.......................................

Thank you!

As long as response times can be in the low millisecond region. I use a probe speed of 2mm per second on my piezo probes which equates to an approach speed of 2 microns per millisecond. At this speed, a 10ms latency would only be 20 microns and fairly reasonable. Having said that, some people seem to use approach speeds for touch sensors in the region of 25mm/second in the belief that piezo and FSR sensors need a good thump. This would give a potential error of 0.25mm

Mike
@leadinglights, for what it's worth I've also been working on an underbed piezo sensor for my delta printer. I noticed that automotive piezo knock sensors use a ring shaped piezo element, with a quite heavy mass glued to them, so they act as more of a seismograph than a microphone. I ground a small flat spot in a 1/2 inch diameter stainless steel ball, and JB-Welded it to the center of a standard Murata 41 mm diameter piezo disc, which feeds a MicroChip 12F1840 ADC input (with very simple clipping and low pass filtering). The results are pretty astounding. It is almost immune to acoustic input (like motor vibration and air horns), but will detect a BB dropping 2 inches onto the bench 4 feet away.

So the trick is to mass load the center of the piezo disc, and support the disc only at its outer rim. No clamps, levers, etc. Just thought this might be of interest.]]> rq3 Next Wave Electronics Working Group Sat, 30 Jan 2021 14:25:02 -0500 https://reprap.org/forum/read.php?181,880687,881072#msg-881072 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881072#msg-881072
As far as Microchip itself goes, they do a fairly good free C compiler but their support for assembler is pretty stinky - annoying for me as I do useful work in assembler but am distinctly handicapped in high-level languages.

Mike]]> leadinglights Next Wave Electronics Working Group Sat, 30 Jan 2021 07:52:34 -0500 https://reprap.org/forum/read.php?181,880687,881071#msg-881071 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881071#msg-881071
I've not touched a Pic for about 5 years, so I fear I'm a bit behind on their tech.]]> majic79 Next Wave Electronics Working Group Sat, 30 Jan 2021 07:32:50 -0500 https://reprap.org/forum/read.php?181,880687,881069#msg-881069 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881069#msg-881069
I have some spares of the Piezo14 board from earlier work where I needed to run a number in parallel. If you have or can acquire a PicKit3 or PicKit4 I could send you one.

Mike]]> leadinglights Next Wave Electronics Working Group Sat, 30 Jan 2021 06:25:02 -0500 https://reprap.org/forum/read.php?181,880687,881046#msg-881046 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881046#msg-881046
I'll take a look at your project - would be good to at least get support for an I2C Probe]]> majic79 Next Wave Electronics Working Group Fri, 29 Jan 2021 15:13:44 -0500 https://reprap.org/forum/read.php?181,880687,881045#msg-881045 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881045#msg-881045 workspace.circuitmaker.com] although I have not used it yet.

An additional question, What firmware will you be using?

Mike]]> leadinglights Next Wave Electronics Working Group Fri, 29 Jan 2021 14:09:44 -0500 https://reprap.org/forum/read.php?181,880687,881017#msg-881017 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881017#msg-881017 majic79 Next Wave Electronics Working Group Thu, 28 Jan 2021 18:49:08 -0500 https://reprap.org/forum/read.php?181,880687,881012#msg-881012 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881012#msg-881012
I'm breaking out 5V for power, but I'm thinking about breaking out the 3.3V Vdd of the MCU - the pins aren't 5V tolerant, so there needs to be some level shifting going on. If I break out 3.3v, then there are a few options for any expansion boards.]]> majic79 Next Wave Electronics Working Group Thu, 28 Jan 2021 16:39:37 -0500 https://reprap.org/forum/read.php?181,880687,881007#msg-881007 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,881007#msg-881007
Quote
majic79
.................................................................................. For probing, you could sync the query over the serial bus before stepping - might slow things down a bit, but that seems an acceptable price to pay.

.......................................

Thank you!

As long as response times can be in the low millisecond region. I use a probe speed of 2mm per second on my piezo probes which equates to an approach speed of 2 microns per millisecond. At this speed, a 10ms latency would only be 20 microns and fairly reasonable. Having said that, some people seem to use approach speeds for touch sensors in the region of 25mm/second in the belief that piezo and FSR sensors need a good thump. This would give a potential error of 0.25mm

Mike]]> leadinglights Next Wave Electronics Working Group Thu, 28 Jan 2021 14:35:40 -0500 https://reprap.org/forum/read.php?181,880687,880999#msg-880999 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,880999#msg-880999
I like the idea, I'll see if I can add it. It would also solve my consideration about how to add support for probes!

Thank you!]]> majic79 Next Wave Electronics Working Group Thu, 28 Jan 2021 12:45:39 -0500 https://reprap.org/forum/read.php?181,880687,880997#msg-880997 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,880997#msg-880997 Examples of external controller boards that I am playing with and which are limited to simple digital IO are:

  • A toggle motor for swapping two print heads. The control board has an input with high selecting one head and low selecting the other. A single output is used from the toggle motor control board which is asserted on completion of a move.
  • An under-bed probe detects nozzle contact for each probe to set nozzle height. The control board is able to detect "soft" contacts indicating the presence of plastic on the tip. Two outputs only, contact detected and contact was good.
  • A touch contact probe to perform the function of bed leveling. This works somewhat like a BLTouch but also checks for baseline drift or mechanical or electrical noise which would reduce the precision of the detected touch. This again uses two outputs, one for the contact detection and one to be interogated before the z-probe operation to find if the baseline is good.
  • A device to measure the cross-sectional area of the feedstock filament. This works by measuring the acoustic back-pressure offered by an orifice through which the filament passes. The output is an analog value.

These controller boards are all very simple and all use PIC16 MCUs; It would obviously be useful to have some form of serial communication such as RS485 so that they could actively have parameters changed. I2C and SPI can be forced to work for this sort of application but they are not really at their best over distances longer than a few hundred mm. Most other serial interfaces need supporting electronics.

At the moment my host controller is an Arduino Mega 2560 with a RAMPS 1.4 which do the job acceptably but trying to add serial communications to a number of other boards seems to be a bit above its pay grade.

Mike]]> leadinglights Next Wave Electronics Working Group Thu, 28 Jan 2021 12:33:11 -0500 https://reprap.org/forum/read.php?181,880687,880938#msg-880938 Re: My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,880938#msg-880938
After some research, I finally got a working design at a reasonable cost. I have an excess of board space, so I was able to layout discrete components to solve that power issue. I have a new found respect for electronics designers - I lost a lot of time trying to figure that part out and fortunately, Spice tells me it will work, and as long as there's no glaring issues with the board layout, I think it should be a workable design.

I'm now wondering if I need to add support for a PINDA probe or similar, and I'm wondering if I have enough pins to drive it. Is it just a Z-Stop and a Servo out?]]> majic79 Next Wave Electronics Working Group Tue, 26 Jan 2021 19:06:08 -0500 https://reprap.org/forum/read.php?181,880687,880687#msg-880687 My little electronics project over Chrismas and New Year https://reprap.org/forum/read.php?181,880687,880687#msg-880687 github.com]

I'm just going to drop this here and ask what you guys and girls think]]> majic79 Next Wave Electronics Working Group Tue, 19 Jan 2021 14:29:43 -0500