DIY Robotic Tester - BoraTronic

[KonradTO]

What I am buiding is effectively a 3D printer rig, except it moves in 2D axis only (in 3d printing the third axis is achieved by moving the bottom mount plate). You will need to buil a syringe actuator which is somewhat of a delicate job - but once you will see my design (using acrylic) - you can 3D print all parts to implement it yourself.

Once I am done with the rig and move on to electircs, I will publish the PCB Gerber files - you can then order your PCB and soldier compoents...

So perfectly do-able in my opinion..

How much do you think will cost in average all the structure+motors? My point is that if you can source the whole structure from a broken 3d printer (or a 3d printer kit) for a smaller price, then you would only need to hack the software (or replace the controller). I am not fluent with 3d printing so I might have somewhat confused ideas on how much a 3d printer can be hacked

 

[Harold999]

Some syringes:

I bought a wrong set of syringes - as I knew nothing about them. Firstly, the needle needs to be at least 80mm. MasterTronic erroneously (probably by design fault) uses 60mm needes and for that reason it's unable to draw the majority of reagent from vials as the vials themselves are 60mm tall (it can draw a maximum of 12ml out of 20ml available, i.e. only 60% of reagent!).

Secondly - there are different ways in which the needle is connected to the syringe: one is called Luer Slip and another is called Luer Lock.

Luer Slip is what you encounter most - by just pushing the needle into syringe until it's firmly in it. Luer Lock is where the needle screws into syringe.

Disclaimer: I don't have a MasterTronic - but I inferred it from reading the MasterTronic manual and studying the technicalities of syringes.

So after getting wrong type of needles (too short), I re-ordered 100x of 80mm needles but these came with with Luer Lock connector. I then had to order new 20x syringes with Luer Lock Connector. Waiting for delivery...

Don't forget that you don't want the needle to go almost to the bottom of the vial, because there is a stirring magnet in there which could damage the needle if it's going in too far. I think this is one of the reasons Mastertronic leaves 8ml in.

 

[dadarara]

can you post a link to Mastertronic internal design ? how it looks like

 

[Borat]

Don't forget that you don't want the needle to go almost to the bottom of the vial, because there is a stirring magnet in there. I think this is one of the reasons Mastertronic leaves 8ml in.

Of course - I understand. But I doubt they need 2.4cm clearance to not hit the magnetic stirrer bit, only need max 5mm-6mm.. Also if you are smart - you can punch the membrane slightly on the side - thereby bypssing the magnetic stirrer bit obstruction altogether.

Mastertronic magnetic stirrer bits are way oversized - I think they were chosen so as to "cover the needle blunder". For this size of device magnetic stirrer bits need to be absolutely miniscule..

 

[Borat]

How much do you think will cost in average all the structure+motors? My point is that if you can source the whole structure from a broken 3d printer (or a 3d printer kit) for a smaller price, then you would only need to hack the software (or replace the controller). I am not fluent with 3d printing so I might have somewhat confused ideas on how much a 3d printer can be hacked

I don't count pennies here - just doing an example build for others to follow. Cost is not my (major) consideration for this build - however I appreciate it might be for some..

 

[JNalley]

@KonradTO 3D Printers can be hacked pretty easily. It's just an Arduino board, most come with Marlin firmware or some derivative of it, but it can be easily flashed to any firmware of choice. All 3 of my printers run Klipper (were once marlin) and I have an R-Pi directly driving the motors, the end result is much faster prints, and the ability to use an accelerometer + input shaping to do realtime calculations and adjust for harmonic vibrations greatly increasing the print quality at insane print speeds.

 

[KonradTO]

edit- I guess I found the answer
Are you are planning to use same test kits as the mastertronic?

 

[Borat]

Most of nitrates and phosphates test require some powder, how are you planning to dispense the powder? You dilute it in RO water first or use tests without powder reagent?

Mastertronic rely on those tests that are based on liquids.. i am not going to do anything different..

 

[KonradTO]

Mastertronic rely on those tests that are based on liquids.. i am not going to do anything different..

Sure sorry, found out myself on their website. I didn't know there were nitrates kits without powder

 

[Borat]

Sure sorry, found out myself on their website. I didn't know there were nitrates kits without powder

Ahh no worries - i had the same sort of questions when i started thinking about this project..

 

[A;exr54]

I wish you -

 

[vahegan]

The thing with the bands range - it is important for a par level sensor (I have been reading about DIY par meters a few days ago as a matter of curiocity). For a test to determine the colour of the solution, or the colour depth - this sensor capabilities should hopefully suffice.

Yes, for the PAR meter, this is a must. For a single test type meter it is probably an overkill. But when you make a single device for several color-changing type tests, that may turn up handy. Also, it would be interesting to compare the absorption of color samples at different wavelengths, to be able to select the band (or a combination of bands) that works best for a particular test. The price of that sensor is higher, but not that high, so it may be worth to give it a try.
When I bought the sensor, I was thinking of two uses for it - one as a PAR meter, and the second as a detector just for the aquarium tests - not automatic one, as you are building, but similar to the universal Hanna tester. I am currently using quite a few Hanna eggs, but there are a few things I don't like about them. First is that for some reason they are using round vials, and their sensor is looking at the developed color from the side of a cylinder. I believe that a rectangular vial with thin walls made of optical glass is much better suited for optometry. In fact, I have purchased a few small (10mm side) vials that were specifically made for optometry. Also, I do not like that these Hanna eggs have no history and no computer/phone connection. I am too lazy to manually record the measured readings into a third party software, and I was thinking to make a meter that would log the results and transfer them to the computer or phone so that I could build graphs and trends. Unfortunately all this hardware lies around waiting when I could find some spare time to put it all together, and write the software to make it work. Sometimes I fear that this would be waiting there until I retire...

 

[vahegan]

Sure sorry, found out myself on their website. I didn't know there were nitrates kits without powder

I think Salifert is using only liquids for their nitrate test. I wish I knew what they use as the reducing agent to convert nitrate ions to nitrite before they can measure it. Most test kits (including Hanna's High range photometer powder) use zinc powder in a weak acid: hydrogen atoms that form on the surface of zinc particles act as a strong reducer, before they combine into H2 molecules. The other option is to use nitrate reducing enzymes - but it seems there is only one company that makes testkit-grade enzymes of this type, and they are pretty expensive. I don't think Salifert uses these enzymes.
Some kits are using zinc suspension in glycerol - but this requires vigorous shaking before it is added to the vial. If Vlad is going to use a stirrer in reagent containers, then using of zinc suspension in glycerol is a viable option.

 

[Borat]

can you post a link to Mastertronic internal design ? how it looks like

If I had Mastertronic's internal design drawings - my job would have been 200% easier... but by now I think I just figured things out on my own: given space constraints certain things simply can be done only in one way.

One thing I am not sure is if Mastertronic uses stepper motors to move the rig (you don't have to - you can do with regular motors provided you have optical switch for start position and end position of each axis). Whatever it uses is very noisy - possibly small steppers with cheap A4988 drivers.. My device will be better in this respect - I will use TMC2209 and they will be dead silent..

 

[Borat]

How much do you think will cost in average all the structure+motors? My point is that if you can source the whole structure from a broken 3d printer (or a 3d printer kit) for a smaller price, then you would only need to hack the software (or replace the controller). I am not fluent with 3d printing so I might have somewhat confused ideas on how much a 3d printer can be hacked

For cost-concerned folkes, lots of parts that I source at "normal price" can be sourced much cheaper from China. I actually looked at the option of buying a small 3D printer kit - but those are no-where cheap.

The other problem with the kit is it sets a constraint on your device size - it's usually of certain size/spect that you cannot change (e.g. aluminium extrusion profile is often larger than 2020). With this build I carefully think how to place different compoents so that they utilise all available space and it's only possible if you are free from being dicated by components.

For the same reason I don't buy/use some standard mount brackets (e.g. you can buy a 90 degree Nema 17 motor bracket) - with a DIY purpose-buit bracket I can get better motor placement and ensure there is no obstruction created..

 

[Borat]

Currently working on syringe actuator - will post pictures shortly..

 

[geddavis]

Wow great job, I have also recently been working on an automated tester not for my tank though. I am working on one for my school’s marine science program to test the local seawater. I will definitely be following along for any cool ideas.

 

[Borat]

Wow great job, I have also recently been working on an automated tester not for my tank though. I am working on one for my school’s marine science program to test the local seawater. I will definitely be following along for any cool ideas.

This looks really cool! Especially that you do it for school... Look forward to hearing your comments!

 

[KonradTO]

Wow great job, I have also recently been working on an automated tester not for my tank though. I am working on one for my school’s marine science program to test the local seawater. I will definitely be following along for any cool ideas.

interesting design! Do you need a special "dark box" for the color detection or any non-trasparent plastic will do?

 

[JeffB418]

If I had Mastertronic's internal design drawings - my job would have been 200% easier... but by now I think I just figured things out on my own: given space constraints certain things simply can be done only in one way.

One thing I am not sure is if Mastertronic uses stepper motors to move the rig (you don't have to - you can do with regular motors provided you have optical switch for start position and end position of each axis). Whatever it uses is very noisy - possibly small steppers with cheap A4988 drivers.. My device will be better in this respect - I will use TMC2209 and they will be dead silent..

It appears that MT uses 2 optical IR sensors and cutouts in the carousel plastic to encode the position of which vial is under the home position.