05/30/2016 at 01:23 •
This is a 4x8 LED array that should work for this project. The PCB is laid out so that I can choose to either go the traditional passive (simple) route or I can drop a couple of 16 bit LED controllers (TLC5940) that listen to the serial interface and have a 12-bit PWM output so I can control the level of light and depending on the LED selection I can also control the wavelength of that light through LED selection. What I have here is a preliminary PCB, there are some interesting drawbacks to using the the TLC5940. One I read about is if the LEDs have power but not your TLC5940, you run the risk of frying your TLC5940. I found this link (http://effluviaofascatteredmind.blogspot.com/2012/05/tlc5940-tlc5941-and-arduino.html) a wee bit late in my initial development of this PCB, but after I get my PCBs back from the PCB house I will do some testing slap some necessary blue wire down and then add some updates to the PCBs.
I think I will modify the overall size as well to exploit the max size the PCB house is willing to fabricate.
05/29/2016 at 02:32 •
All plants need light, at least the ones that I will grow in the SCGA.
I have some work completed on the LED board that will supply the light to my plants. I did some research and read that there are two specific bandwidths of light that are the most beneficial for plant growth. Quick Google brought me to this -->https://www.illumitex.com/impacts-colored-light-plants/Red light (640nm-680nm)Blue light (430nm-450nm)
I will focus my efforts on these two spectrums and develop the necessary PCB to provide just these two for the added light for this project.
05/26/2016 at 00:20 •
Last night I sat down and wrote a bit of code to test the experiment PCBs. I have a servo, a DC motor, (ran by PWM from an analog input) to adjust the duty) and the LED connected to pin13 working. I did notice that I forgot my soft pull down resistor on the digital input switch that I added. OOps. Blue wire to the rescue, should be easy enough, there is a ground trace close to the switch that I can tie a 1k0 smd if I scratch the coating off the trace and drop some slobber.
If anyone is following my other project, you will notice that these logs are very similar. If you don't like it, please feel free to add a comment and I will correct my way of working.
05/24/2016 at 01:01 •
The PCBs (to test the not yet written software using the Teensy3.2) have arrived and they test OK (except the one that I soldered the LM317 in backward!). I used an L293 Dual H-bridge driver for the fan and peltier device control. This way I can make the device shuttle electrons either way to warm or cool the heat-sink . The same goes for the fan, though I am not certain it will be necessary to drive the fan in both directions. The fan might end up being controlled by something else and I may use the second channel to drive a peristaltic pump, but again I don't know that I will need to drive that in different directions.
04/28/2016 at 11:27 •
PCB was designed and sent to the board house. I will post files after I recieve the PCBs and test functionality.