The first application we've put the 3D printed orbital shaker to work on was agitating containers with samples in it for this red cabbage pH protocol. The protocol is simple, takes just minutes to do, and depending on the sample you are testing, can work instantly or require a bit of agitation which you could easily do by hand, but we have an orbital shaker so why not use it?
One sample (pictured below, left) was actually homemade soap. The middle is coffee, and the right is regular tap water. We also later tested lime juice which instantly turned the cabbage juice red-pink.
There are scales online showing the different colors red cabbage juice will change depending on what pH it is exposed to. The image below was taken from here.
We've been making DIYbio lab equipment mainly just to make it and put it out there for others to use, modify, and improve on. The designs for our equipment are freely available on Thingiverse here. We haven't been using it for too many applications of our own yet, but we have used the centrifuge to extract DNA from rice, and now this pH protocol shows some promise.
What would you use your shaker for?