Arduino TDS sensor: Part 1

I just wanted to post a quick update that I’ve managed to hit another milestone on the smart garden. This time on the technology side of the build.

The other day when I ordered up a fresh tube of caulk, I also ordered myself a TDS (Total Dissolved Solids) sensor for the arduino, so the garden will be able to monitor the strength of its grow solution and let me know when I need to top it up. When I ordered that TDS sensor I also got myself a set of handheld pH and CEC sensors, to further monitor the hydroponic solution. Perfect world, I would have preferred to buy a pH sensor for the arduino, and have it self-monitor that as well, however the price for that sensor was twice what I paid for both the handheld pH and CEC units added together.

All of those lovely bits of technology have been delivered, and I’m expecting the caulk on Wednesday.

Yesterday, when I had a few minutes I found and installed the arduino data library for my new TDS sensor onto my PC.
This morning, after I finished reading my Greenhouse lesson for the week, I decided that I would hook up the sensor and try getting the arduino to recognize it.
The sample sketch (program) that came with the library installed onto the arduino without a problem. The difficulty came when I tried to get the arduino’s output to display correctly in the serial monitor on my computer. Instead of numbers, the display was generating accented ASCII characters - mainly accented letter c.

A quick trip to the arduino forums later, and I found I was not alone with this problem. This seemed to be a common problem among users regardless of sensor or program that was being used, and the suggested solution was to adjust the baud rate between the arduino and my PC. As soon as I ramped the speed up from 9600 to 115,200 I was seeing my results.
Mission accomplished!

As a test I compared my tap water, which had around 280ppm dissolved against some coffee, which was around 520ppm.
I was happy to see there was a difference

Next up… and this should be a fun one… grabbing up a wifi module, and see if I can get my tablet to see this same info wirelessly.