Injecting, Need to Colorometering

A project log for Reagent Robot

Automate the Reagent (take a sample, put a drop of stuff in, shake, look at the color) testing of water for Aquaponics, Ponds, Aquariums.

james-newtonJames Newton 02/09/2016 at 01:141 Comment

Haven't touched this in a while... honestly, I think it's because I had a really bad experience at an event where I was showing it (as well as doing a workshop) where the organizers had a rock band inside the worst building for sound reflection ever... Our ears were ringing and that means hearing loss. The lead guy was nowhere to be found and none of the people he left in charge was willing or able to pull the plug on them or turn them down. And no amount of screaming, yelling, or trying to unplug them physically would stop it. They played the full set at full volume and I had to pack up and leave. Kids in there were injured, but no one cares about hearing so forget about reporting it or owning up. When I tried to express my shock and outrage after the event, I was censured (probably appropriate, I posted publically when I could have done it privately) and banned from future events (possibly appropriate, sad) and my friends, who I was NOT exhibiting with, were also threatened with a ban (VERY inappropriate). That seems to have lifted as he cooled off. So my upset and hurt feelings over that transferred to this project and have made me want to leave it alone. That sort of thing ever happen to you? I'm ready now to get back into it.


So the injector is working fine, I used an LM317 with resistors to give 6 volts for accurate power supply and max strength to the servo. It /seems/ to be very consistent in it's movements but I'm not sure it will be accurate enough.

If I were starting again on this project (and I'm sure I will end up doing so after I find out all the things I've done wrong in testing) then I would use a stepper with two shafts (either end) and the top would run the injector while the bottom shaft runs the wiper / stirrer. Just crashing forward for now.

I need to get my butt in gear on the colorimeter and then get it hooked up to water and see what's wrong / how badly it works so I can take notes, document, then scrap the current version and start over.

Colorimeters don't seem that hard, I just need to wire up the circuit and add some code to the Arduino to run my light source and read the frequency back from the

I have some TLS235R and TLS237's and I'm following the basic instructions from

but they use TLS128's... not sure why I didn't get those... must have been a reason. Just need to make up a header to plug the sensor into and then wire that cable to the Arduino... then I'll probably just tape the sensor to the outside of the reaction chamber.

I have an Adafruit Neopixel or two which I'll probably start with, but I may need a more accurate light source... we will see. LED's are cheap. I'm hoping I can measure all the colors with the one Neopixel instead of having to wire up multiple LED's. Again, cable, tape to chamber.

Should probably seal the cables with silicone / heat shrink because they will almost certainly get wet.

A client wants to measure multiple frequencies for a separate project so I'll probably start with:
and see if it works. Should be well in the frequency range at less than 10KHz.

If anyone has experience with any of this... or even just read it... please let me know.