MicrobeHunter.com Microscopy Forum

Hey folks,

So one of the cool things I've done with my BH2 (BHT) microscope is hook up magnetic linear encoders to the X/Y table. This gives me a real time DRO on my computer screen while I poke around a slide. It's great for a lot of reasons - one example is, if you see something you want to look at later with oil immersion, you can quickly mark the coordinates and go on to other things (and possibly more markers) before committing to oiling the coverslip. Obviously you can technically do this with the Vernier scale - but that's a pain and way less accurate.

The next thing I'd like to get going is automatic objective selection detection. This way, when I'm streaming or taking video, I can automatically apply the correct scale bar when I rotate the turret. I have a few ideas:

1. I could paint white stripes on the turret's rubber ring aligned with the objective ports to make crude barcodes. Then I could use IR sensors to read the presence or absence of a stripe and call that 1 or 0. Seems feasible, but if I change objectives or the whole turret, I'd have to change settings on the software end.
2. I could put small QR or similar codes on the objectives themselves and get a small barcode reader. Could be a little difficult and more expensive.
3. I could put mini and/or flexible RFID tags on the objectives and use an RFID antenna at the viewing position to read them. The most elegant of these ideas I think.

That's what I've come up with so far, but I would appreciate hearing any other ideas or if you've done something like this before.

Thanks,
Jason

I like the idea of QR codes for this job … they are robust, and can include a lot of information.

There are many generators/readers available … but the one that I use, for general purposes, on the iPad is this:
https://apps.apple.com/gb/app/qrafter-q ... d416098700
https://qrafter.com/

[ no connection other than being a satisfied user ]

MichaelG.

A couple of years ago I used 25mm diameter flexible writable NFC tags to label my chili plant containers. They were self adhesive on one side, coated on the other (water resistant). The description states a read range of 1-5cm but I felt it was in reality at the lower end of the range. I used a free phone app on my Samsung Note 10+ to program the tags. Something like that might work for you as long as your reader wasn't accidentally picking up the next objective in the turret.

I'd be curious as to your encoder project for the stage. I want to do something similar -- ultimately I want to motorize my stage with joystick control, and encoders that can store locations and "tours." If you could share more information on exactly what you did with the encoders, I would really appreciate it.

I like your DRO idea - and hope you post a thread on it.

As for the objective magnification feedback, here's one more possible approach:

- Three lines, bars, or dots, read by a small photodiode array, would cover up to eight objective magnifications.

- There's room behind the turret (away from the operator) on your BHT stand to place a three-diode array and lamp. Lots of ways to toggle the lamp on and off to make sure you have enough light to read your binary code.

- Print the codes on strips of paper (white plastic sheet etc.) and use transparent heat shrink tubing to fix them around the upper side of each objective. A plus with Olympus is that DPlans, SPlans, and even SPlanApos are cylindrical rather than tapered at the upper end. Apply the coded strips and clear heatshrink tubing with each objective screwed into the turret, so you "clock" your code so it can be read from the back.

Thanks for the ideas, guys - I like the heat shrink idea especially for laminating on barcodes, although I’ll admit I’m a little hesitant to point a heat gun at my high performance optics

As for the DRO - yes I will absolutely be sharing this process. I need to refine it a little and it’s not going to be a straightforward process unless you have my exact setup, but tinkerers should be able to get it to work.

This is the encoder module I use: https://ams.com/as5311adapterboard#tab/description

And this is the tape that it reads: https://www.ebay.com/itm/165397757686?var=464953115264

I actually use a Nikon table because it was a lot easier to mount the tape and sensors with just hot glue and some shims made from plastic microscope slides. I’m sure with a few 3DP parts the same could be done on an Olympus table.

Here's a pic of the X sensor - the Y sensor is mounted on the left side underneath - you can see wires going over to it in the background. It all goes to an Arduino which handles the bit banging and spits out encoder counts onto a USB COM port. I pick up the encoder counts in a C# Winforms application and display them in a window. I'll probably change to a Python app in the future as it's a little easier to iterate on.

The real nice thing about this is that there is no mechanical interface between the static parts and the sliding parts. So no impact to the feel of the table as you manipulate it.

I think that on the BX, one manually registers an objective into the software. The software recognizes the objective that sits at the optical train, and the ordinal number of the turret position. One installs the objective and tells the software which one it is, in the operating software of the motorized microscope. The barcode sounds an even better approach.

Hobbyst46 wrote: ↑

Sun Jun 04, 2023 8:11 pm

I think that on the BX, one manually registers an objective into the software. The software recognizes the objective that sits at the optical train, and the ordinal number of the turret position. One installs the objective and tells the software which one it is, in the operating software of the motorized microscope. The barcode sounds an even better approach.

Yeah I change out my objectives and even my whole turret pretty regularly - I want everything to "just work" no matter what I do.

josmann wrote: ↑

Sun Jun 04, 2023 7:12 pm

Thanks for the ideas, guys - I like the heat shrink idea especially for laminating on barcodes, although I’ll admit I’m a little hesitant to point a heat gun at my high performance optics . . .

The other option would be something like Brother P-Touch tape. I'll use the clear or silver stuff to re-label objectives with worn lettering.

I've used heat shrink tubing on some cheaper lenses. The shells often unscrew and separate from the lens body. And the pencil-type hot air guns provide pretty good control of the heat and shrink.

You could look for a Leica DM RXA, The nosepiece is motorized and encoded, the focus control and stage x/y speed is automatically adjusted for the objective in use. Contrast methods are automatically detected and with the right Leica digital camera, meta data from the scope and the camera is captured with the image. Also all remotely control via the integrated LAS software. The most recent incarnation is the DM6000.

wabutter wrote: ↑

Fri Jun 09, 2023 11:38 pm

You could look for a Leica DM RXA, The nosepiece is motorized and encoded...

Directly encoding rotational position within the turret is what's done in the CNC world for tool selection:
Second most elegant solution for lens ID would be those sexy stick-on metallicized mini QR codes: