Adding a data port to a Spectrophotometer 721

So as you all know I have recently purchased a cheap spectrophotometer , I thought it could be useful in the lab for some biology projects I've been working on. But as most things in my workshop and probably yours, upgrades are always on my mind and I like to see how far I can modify. In this case I wanted to see if it was possible to connect the spectrophotometer to my computer, that way I can visually see the curvatures in data and get a better idea of what is going on. 

ISP PINS

    Now I dont have any electronic testing equipment other than a multimeter so my investigation will be basic, mostly to see if there is any change in voltage levels while changing the wavelength. My initial investigation started with the pins I found during my tear down they as you can see in the photo are labeled as ISP . 

    The five pins being in this case GND, DTA,+5V and RST. Just to knock it out I tested the 5v line and as expected it was just as it said. From there I wanted to see if there was any significant voltage coming off the data line and from my surprise there was 5v. Now this might be common I honestly dont know but it really wasn't helping my on my voyage to a interface. The journey must continue so I decided to look at other possible areas of connection. (Really need to buy an oscilloscope)

SILICONE PHOTODIODE CONNECTOR

    The only other connection on the board, is the silicone photodiode as you can see from the above photo. The photodiode connects with a +15v ,-15v , GND , AGND ,Signal (believe it was misspelled) and 5v. 

I tested the Signal and AGND pins and they showed a relation between wavelength change and voltage levels. The voltage peaked at about 6.60v ±.05 at roughly 660 nm and 548nm and bottomed at .41v at 350 nm.  When I brought it to the highest wavelength (1020 nm) voltage came down to 3.5v .

So now that I have narrowed down the data/voltage line, the plan is to use an Arduino Nano Knock off (I'm cheap) and a Cheap Arduino Voltage Monitor ($4) to bring this data to the Serial Plotter.

Current wiring plan is the following :

Now the next part is how to organize all of this on the inside of the spectrophotometer. I like having things clean and tidy , so I put a little time into designing a nice holder for the electronics.

3D Printing

Epoxy went a little crazy, ohh well it works I guess

And for all those that love 3d printing info, PLA at 100% infill because I just wanted it to be strong. Also designed in Tinkercad because I enjoy using it.

Mounting

Positioning it was difficult, the biggest issue was determining where I had the greatest amount of clearance. Getting it as close as possible to the circuit board just makes life easier. So I decided to mount it just below the circuit board.

Need to clean up the wiring and probably trim a few wires.

I didn't like how my cut came out , so I hid my rough cut with a 3d print. Just a simple border so all you can see is the micro USB.

Data

With time I'm going to write more code to handle the data but for now here is some data from the Arduino Serial Plotter .

The voltage is all over the place but when sitting at a specific wavelength as you would when using the spectrophotometer , you can monitor the change in voltage , which is directly related to the amount of light passing through the sample and hitting the sensor. The photo below is 660 nm light passing though a sample of water with a drop of Blue food coloring.

Almost 100% of the light was absorbed by the blue food coloring.

Thoughts

This will become more useful when I get a chance to write some code. Overall I really enjoyed this project , and hopefully I get to use this modification in my lab.

I hope you enjoyed the read , if you have any advice or ideas on improving this idea. Feel free to contact me .

721 Spectrophotometer tear down

There will be more projects relating the to 721 Spectrophotometer but I thought I would start this little series with a basic tear down of the machine.

So the machine came in a very nice box, very well packaged and for the price I paid, it's higher quality than I originally expected.

The tear down started by unscrewing the sample holder rod then removing the wavelength knob and the 2 bolts on both sides. From here the white plastic top simply lifts off.

Overall simple design most of the left area is taken up by the lamp and the defraction gradient which unfortunately couldn't be accesed without me possibly damaging other parts. From here you can spin the wheel on the left side to modify the wavelength being used. On the right side you mostly have the sample chamber which is built to hold 4 separate samples and the detector.

I'm thinking of modifying the sample holder or at the very least 3d printing some adapters for some light fun.

Two separate circuit boards were inside the case, one to power the lamp and the other to control the screen.

The circuit that controls the screen really got my attention , I would like to see if I could do something with this "ISP" connection. Haven't identified any of the chips yet but getting a data port in here would be nice.

So there will be more projects on modifying the spectrophotometer later on but I hope you enjoyed the basic tear down.

Funaria hygrometrica pot

Been collecting plants for years and have been a fan of moss all my life.  It's a simplistic plant and after all these years I'm going to try to keep it in an indoor pot. Luckily living in the county side has given the ability to source my own moss. I filled the bottom with high quality dirt and compressed it pretty hard. So I just went outside one evening and started to fill a small indoor glass pot with cord moss. 

I give it a light spraying ever day to keep it moist and so far its doing pretty well. 

Also I think the pot is beautiful , I was given a load of old milk glass and am slowly going through it.

Custom Vivarium Lamp

So you probably already read my Vivarium build well as much as I love the Vivarium,  I would like to provide it better lighting and have it near my chair. So here we go , I started this build by drawing a simple pixel art of what I wanted (I just like doing it for all my projects).

The main parts of the project are as follows:

• Two round modules for mounting the LED strips

• Oak base

•Led strips

•Mount to hold the metal square tube 

•Cap

The round modules are probably the most complex part of the build mostly because you have to take into account for the leds strips, wiring and attaching it to the 19mm square tube. Took me two tries to get it just right but in the end it worked out beautifully. All the CAD work was done tinkercad. 

 

Originally I was going to cut a hole into the oak to hold the 19mm square tube but I decided to go the easier route and just 3d print a holder for it.

(At this point I simply need to drill a few holes and wire the led strips)

I didn't think it was going to be to bright but turned out I was wrong. So I built a simple shade to cover the brightest parts of the light. The leds get slightly warm which provide heat to the terrariumm

Vivaruim build

I've had a terrarium for years and it all started from one of those Venus fly traps you buy from Walmart in the summer.  The venous fly trap eventually died but I decided to keep the hard plastic container to see if anything else would come to life.  And with a little patients it eventually did the peat moss around the Venus fly trap sprung to life and took over the container but let's fast forward about 15 years.  The plastic container started to die due to sun exposure so I decided to swap the container for a large pickle jar.  I decided to remove 90% of the peat moss due to it having negative effects on growth.  I also increased the water level by 30% making the original soil extremely moist.

I brought in several different species of moss and lichen and plants to create more competition for the peat moss. Also added a piece of tree bark to add dry surface and soil coverage.

•peat moss

•small unknown plants (waiting for more growth)

•reindeer lichen

•Tree Bark (Male Persimmon) 

To keep the moss and lichen from over taking the new container I decided to add some isopods and snails. I wanted this to be a self-regulated biosphere. I know isopods like both a dry and wet area so I decided to design a small hideaway for them to explore during the day. 

The structure was 3d printed with grey PLA at 100% infill to stop any possible warping by heat. Long term hope is that the the mosses eventually over take the structures roof allowing it to blend in with the rest of the terrarium. One end of the hideaway is open and the other is closed with a piece of rock moss and reindeer lichen. Some small rocks were added for other areas to hide and explore. The hope is that the moss takes up most of the open soil,  I believe this will eliminate or decrease the amount of sitting water.

I will update periodically with updated photos of the growth and life I discover in the Vivarium. If you enjoyed this reading check out my custom lighting I built for it.

Laser Mount for Telescope

A few years ago while walking around Good Will I found a cheap telescope . It wasn't anything fancy just a 15-20 year old refracter,  they only wanted $5 for it so I picked it up.

It sat in the closet for a while,  it needed alot of TLC. All the bolts needed to be replaced and everything was simply to loose. There was to much play to make it a useful scope. Luckily all the new bolts and washers removed all this slack.

 

Unfortunately someone probably years ago removed the "finder scope". Which make it easier to align up to the object you want to examine. To solve this issue I decided to mount a semi high powered laser I had laying around.

Originally I decided I was going to attach it using velcro straps but I eventually mounted it using adhesive.

I didnt expect it to be perfectly aligned, it was pretty obvious even a small angle difference would effect the alignment of the scope and the laser.

If it got me close to the location of the object I was trying to view , I would consider the project a success.

Overall I consider the project a success.

Fecal Examination Microscope Slide

Quick project 

A few months ago I had a friend approach me about the idea of examining the fecal matter of a goat to see if the goat had worms by looking for eggs. After some research I found out they do manufacture such a slide, but I thought they were a tad expensive. The design is relatively simple with it mostly being a counting square in the center wedged between two slides.

I took a microscope slide and as close as possibly engraved a counting square in the center of the slide. After it was done to make it more visible I filled the engraving with blue ink.

To to create a space in between the two slides I simply broke the a slide into multiple pieces and sanded to the needed size.

A small drop of adhesive holds the two pieces in place. Decided to add an 3d printed casing to the ends to hide all my ugly glueing.

This slide probably won't work as well the official version but if it works well enough for me to count eggs then it did its job well.

Thanks for reading