tekkydave

I used one of these in my RPi based weather station. I also used the owfs file system to provide the connectivity to the 1-wire sensors. It just presents all the sensors as a virtual file system mounted on your RPi's file system. You can then access them directly via a script/program on the RPi itself or connect remotely to the RPi from another system running owfs (RPi, PC etc). I have an RPi in my external weather station box which also has a WiFi dongle attached. This connects to my house WiFi system. I also have another RPi indoors pulling values back every 15s over the network. This RPi also runs a small database and web site for viewing the data.

The Precision Piezo kit arrived so I spent this afternoon putting it together following their instructions on Youtube. Then connected it up to the DBot Ramps to calibrate and test. It only needs the standard 3 endstop wires (Gnd, +5v, Signal) and will work on 5v or 3.3v. The video below shows the unit triggering (blue LED)

Santa's bringing me one of these for Christmas (don't ask me how I know ) - Can't wait to go 32-bit and quieter stepper drivers etc. Will have to wait till Christmas to open it though . I've also ordered one of these to try this new way of probing the bed. The servo arm with microswitch method I'm currently using just isn't reliable enough.

I have added an extra piece to support the front of the platform. This has allowed me to put wheels in all 4 corners of the platform to better support the weight. At the same time I have changed the 4-wheel carriages to 3-wheel. These are much easier to align. The carriages I used from Thingiverse also have an M3 bolt to adjust the tension. I have also moved the leadscrews to the centre of the platform as this is now the centre of gravity. I'm still considering an upgrade to a 3 leadscrew system powered by a single motor.

Just checked and it seems to be ok. Could have been a temporary problem.

I discovered I had a complete servo/microswitch assembly left over from when I experimented with bowden on the Prusa. I printed a modified fan mounting to accomodate the assembly then fitted and wired it all in. The orange coloured parts are the ones from the Prusa. I have amended the Marlin config to suit and it just needs calibrating now. I also assembled & fitted the power switch/SSR enclosure.

I'll have to see how it goes I think

Thanks, I'll have a look at those

I have yet to implement auto levelling on this printer. I haven't decided on proximity or servo/microswitch. Any thoughts?

Yep. 300x300x6mm ecocast Ali adds a bit of weight. It's not too bad if you get it balanced but a bit fiddly. To be fair I used to get backdriving on my Prusa using the 4-start screws. They are not really suitable - 2 start would be a good compromise between speed and accuracy I think.

Yes, I was considering doing that myself. The D-Bot is designed for light PCB style heated beds not the 6mm Ali like I'm using. The cantilever is not really up to holding the weight without a bit of droop. Some use 3 lead screws which is what I'll try first as it is easy to implement but I may end up going the way you have. I may do it as a general upgrade to 3-wheeled carriages all round.

I took a trip to B&Q the other day and picked up some 1mm thick discs for my angle grinder. Today I shortened the new lead screws to 410mm. I ground an approximate 45deg finish on the cut ends to avoid any nasty burrs. I didn't bother trying to clear the threads as the cut ends will be in the flexible couplings. I fitted them to the D-Bot and they work very well. The bed doesn't back-drive the motors now and move down under it's own weight I temporarily changed the Z steps_per_mm to 3200 using M92 for testing: M92 Z3200 I need to make this permanent in the firmware and also adjust some of the speeds as the movement is far too fast for these screws, especially the Z homing speed which tends to stall the motors. I have a 3rd screw and a spare motor so I'll be trying to add it in at some point to give better support to the heavy bed.

Good progress, Gina. I love your "make it up as you go along" methodology. I don't have the confidence to do that myself. I tend to take working designs like the Prusa and D-Bot and make improvements where possible. Best luck with your build

Ooo, another printer topic. I'll pop across and read up so far

I've also been busy designing and printing an enclosure for the IEC C14 inlet and Solid State Relay. The plan is to keep all the mains voltage wiring together and separate from the rest. A mains feed from the box will feed the power supply. The SSR will have 12V input from the RAMPS and mains output to the silicone heat pad.

The new leadscrews arrived this p.m. They look pretty good quality with nicely finished ends. These are 8mm dia, pitch 1mm, lead 1mm, single start. For some reason I ordered 500mm length, but I need 400mm for the D-Bot. I'm not sure how easy they will be to cut. I'll have a go with a hacksaw or maybe my angle grinder. The narrowest metal-cutting disc I have is 2.8mm. Maybe a 1mm would be better.

I've ordered some single-start T8 lead screws. These will have a pitch and lead of 1mm as opposed to the 8mm lead my current ones have. This should stop the sagging (hopefully). I've ordered 3 so I can upgrade to a triple drive system at some point.

Yes, I thought ABL would not be relevant. Maybe some kind of braking mechanism is needed or keep the z motors energised. In a normal printing situation its not an issue as they are permanently energised during the print.

I have temporarily connected up the heat pad via the SSR to test it. The bed now heats from room temp (21C) to 65C in about 30 seconds. Should be fast enough . No picture as I dont want to encourage exposed mains voltages I did add a grounding point to the metal part of the bed for safety. The glass arrived today so I installed that and did a PID tune for the full shebang. I discovered that the thermistor types used in a lot of these beds needs to be set up as type 75 in Marlin #define TEMP_SENSOR_BED 75 One thing that is now happening is due to the weight of the bed it now sinks down the leadscrews under its own weight when the motor power is off! Maybe some anti-backlash nuts might help, I'm not sure.

I've also ordered a piece of 300x300mm borosilicate glass from Ooznest to give a nice build surface.

I have drilled the mounting holes in the bed plate and countersunk them so a glass plate will go over the top. Today I attached the heat pad to the plate and fitted it to the printer. I cut some PTFE spacers from some bowden tube to keep the metal mounting screws and springs away from the cut corners of the heat pad. I'm sure the heater wires are still about 5mm from the cut edge but you can't take any chances with mains voltages. I needed to adjust the positions of the z motors, bed mountings and z carriage 'arms' to accomodate the larger bed. I also moved the z motors forward as the centre of gravity of the combined bed assembly had moved forward significantly. I should have removed the entire assembly from the printer and found the balance point manually but I think I have it in approximately the right place. I intend to upgrade to three lead screws with a single motor at some stage so it will all get rearranged at that point anyway. I have connected the bed thermistor up to the RAMPS and updated the necessary Marlin configuration, moved the endstops etc. Next step is to wire up the heat pad to 220V via the SSR. I will also be ensuring the metal parts are all grounded and the bed supply is also fused.

It should work but you will need to rewrite the clockwise() and anticlockwise() functions to suit the stepper controller. Good luck.

Thanks for that To be honest I haven't even touched my scope for a couple of years now <shame>. I seem to have been completely taken over by the 3D printer bug.

A couple of pics: I would strongly advise anyone doing something similar to get a slightly oversized plate, e.g. 310x310mm or 320x320mm to make life easier.

The Silicone Heater I ordered has arrived. I made the mistake of buying a metal base 300x300x6mm so leaving no room for the mounting screws. I have managed to snip approx 6mm diagonally from each corner of the heater to clear some space. I could just see where the wires were inside the heater and I had my DVM connected measuring resistance but it was heart-in-mouth time whilst cutting Next job is to drill and countersink 3mm holes at each corner for the mounting screws.