Differential IR height sensor, Attemptin' Clone....ain't sure of success...now stage 10

Ho Puff, Thanx for the info.......Nice printed enclosure.........I'll be designing an enclosure as soon as design is proven & waiting for PCB bare brds to arrive.........Hoping to install in Robo by some 'rubed' method today.........I used a SMT electrolytic cap in PCB....shorter height, think it will still block e'nuf of the IR side scatter. Waiting for your install this weekend...keep me posted.....Jimmy

 

this looks great! Looks like a great amount of sensing distance

 

As far as repeatability goes, the following results was obtained after running 16 x G30 commands while the x and y axis was stationary.

First the servo and limit switch values

21.62 x 1
21.63 x 7
21.64 x 6
21.65 x 1
21.66 x 1

Next the Mini IR results

0.98 x 14
0.97 x 2

Im very happy, no more moving parts on the auto bed leveling.!
Better accuracy as well.

Next step is to split the sensor in two and only have the IR stuff right in front of the nozzle under the fan, as opposed to on the side that it is now.

Jimmy, this is still version 1 with C2 where it was, I have new PCB's comming with thicker tracks and C2 relocated as per your suggestion. (Mainly to fix the swopped anodes and cathodes).

Getting here was not without incident, I shorted the one GL4800E0000F while fitting it and had to replace it.

Also I can confirm that the following two za.rs-online.com components will work: RS stock no: 577-538 and 666-6476 with Dave Crocker's original resistors.

 

Puff, Your the man..........You are moving fasssst. Only installing mini today.....new cable Zmin 3 cond. created & installed in Robo yesterday. I'll post some pics of the cable, ended up being 48" long........spent most of day removing the 3 bearings from extruder, cleaning hot end & heat-break, greasin' smooth & threaded rods, etc. Pencil drawing of mini support bracket.....will model today....install in robo, after extruder removal & re-install. I seem to have a greater sensing distance, sub'ed the IR's..........test will reveal.......I'll slot the support for Z tweaking & ideal height from bed..........

Your numbers are going to get many excited.....................Jimmy the greek geek.............

 

Mini IR Cable - 48" length, 3 conductors of 24awg teflon stranded, Berg Contacts & 3 pos 0.1" pitch receptacle, heatshrink- here & there....

 

Hmmmmm, I think Mouser came up obsolete when I tried ordering those..........Thanks for the info, I'll keep that in my back pocket.....

 

Here's a small bracket, modeled, and printed with PLA that's been setting unsealed in 85+ weather for 2 months, kinda crappy print, but should work for mounting onto the extruder lower carriage. It will mount to the existing screw & acorn nut......

 

This project is really cool. Awesome work guys. I just moved this to my wish list of upgrades. Wonder if this will be standard on the Robo3D R1++

 

Thanks Danz........I also sent qty 16, G30 commands last night, with nozzle centered on bed, for base line robo repeatability data, with the limit switches......the Z results are:

X110.00 Y110.00 Z *****

******
0.04 x 3
0.03 x 1
0.05 x 1
0.04 x 8
0.05 x 1
0.04 x 2

Deciding to add a True/False jumper to the mini to include either digital logic conditions from various limit switches, saves "experts" like me from messin' with the firmware..........take care........

 

Just ran tests again this morning........this time z nozzle was lifted +10mm between tests, the results:

0.06 x 4
0.05 x 2
0.04 x 2
0.05 x 1
0.04 x 1
0.05 x 1
0.04 x 1
0.05 x 1
0.03 x 1
0.05 x 1
0.03 x 1

 

Alright, had to pull the trigger on this. I just bought the IR sensor and can't wait to see it work in person. I just have the stock hex extruder, but I am sure it will work the same. Just need to come up with a way to attach it. Jim, will your mount work for both the stock and E3D?

 

Good news! You are welcome to the STL file, the bracket mounts with the existing single extruder carriage screw. I modeled in under an hour, most of that time was robo fit measurements......What is the ETA of the mini?........bracket fits, should be mod'ed to captive the rear board nuts......I think it will fit as long as your fan isn't in the front.

Messing with config.h in arduino now.....but, moving forward.....keep me posted.........Jimmy

 

Progress on Mini-IR, Mod'ed code Z min from "true to false", flashed EEProms, eyeballed mounting..to my surprise, right on.....I'll do better tests with hot nozzle & bed tomorrow...think 'bout better mounting...and MK or Danz if one of you can give me the center to center of the two mounting holes, that would be great......PC designed as above but may revise a little after further tests...take care.....

 

Jim

My IR mini should be at more door on Monday. If Mike doesn't get you that measurement before hand, I will get you that Monday evening. Just got my leadscrews replaced and now I am ready to ditch these z stops for something way cooler. Nice video btw.

 

FIY from David's blog:

Board dimensions and mounting holes for version 1.1 board
If the bottom left corner of the board is position (0, 0) then other points on the board are at the following coordinates, in mm:

Top right corner (24.0, 17.62)
Mounting hole centres (2.70, 14.92) and (21.11, 14.92)
Mounting hole diameter 2.8

 

Thanks Puff, You know, might of seen that at one time in his blog...............appreciate the info............hope you are makin' out OK with the separation thing. Careful with the photo receiver tho...........code is looking for small voltage changes between partially on & saturation currents..........milli'volts......

 

Thanks Jimmy, my printer is running fine with the sensor on the side so splitting is not a must. It would be nice as the z leadscrews are the only variable that could change and having the sensor in front would counter that. Still waiting for the new PCB's with the IR legs the right way around and the two part PCB. But like I said no urgency. I should be installing the second sensor in the next couple of days.


Sent from my iPhone using Tapatalk

 

Hi Jim, great work! I would love to try this on the Mowi printer i am designing. It is a foldable printer and as the folding messes up the calibration i really like the autobedlevelling. I am using an inductive proximity sensor now but that is not so convenient. It needs aluminum tape on my bed which i then have to cover with kapton or painters tape. I also ordered a PiBot Optical Reflection Endstop that I will test as soon as i receive it but i have the feeling it will not be as precise as Davids design. As they didn't share much specs either it will be way harder to adapt the design in case it doesn't fit on my printer.
Anyways, I'll get the parts together and try your diy version of Davids design. It seems the capacitator is the highest component on the board. As i have some space issues i would like to replace it with something lower. Do you know if there is an alternative? I'll put something else between the leds and phototransistor. Is there also a way to change the detection distance? In your video you are talking about changing the value of R3. Would that help?

 

Mowi, Thanks for the response.....my take on R3 resistor revision.........stay with the values as David recommended for now. I subbed the pot because I subbed the IR Emitters.....Wanted to be certain, I had the ability to tweak the far LED's current to match the the near LEDs received IR output.

I think, bottom line, you want the photo-transistor to receive the same energy from either IR Emitter at the same distance from the bed.

Since the far IR LED light, must travel further than the near lR LED, the far LED must be driven harder with lower resistance/higher current to compare apples to apples & oranges to oranges.

I'm thinking greater sensing distances will result in less repeatable results, ain't sure yet...that's later.

A method to test sub'ing parts may be: Use a photo-transistor & two IR diodes. Mount as in the circuit 90 degrees from each other & 45 degrees from the reflective surface. Apply power to near LED, measure voltage from photo-transistor, record, remove power then apply power to far LED. Record voltage, and tweak LED currents to match voltages received. That way you can play with different combos.

I will shoot a video tonight, I hope, to explain the operation of the circuit.....as I see it............anyone feel free to correct flaws in my interpretation. I think this new video will help you with 'understanding the mini ir'..............Take Care