Hydro Spinach version 1 day 3

Day three

I replaced the 12V power supply with a bigger one. now there is 120W of power and that should be plenty. Now the idea is that the HydroSpinach growing machine runs without supervision on its own. To have this done safely I think I need the fuses. LED grow lights for example take 72W. If there is a malfunction and it sorts the power supply will automatically cut it off after the threshold load is reached. I assume that it is somewhere a bit higher then 120W. In case of malfunction on this quality 🙂 LED strip from China and it shorts but the threshold is not reached. It still can cause a hazard. Lets say its starts heating up and uses 144W that is the double it normally uses. It might be the case that it will combust in to flames and the power supply is not aware of the short. This is why the fuses are needed. So for the grow lights I think I would go with 80W/12V =6,6666... amps so a fuse as close to that as possible. Also for the rest of the power lines in the machine. Same principle. I want the fuse to burn before my workshop does 🙂


I been test running the HydroSpinach for the last week. Noticed that the temperature meter that is mounted on-top of the grow lights is getting some heat from the lamps bellow it. I took a piece of foam and made a 5cm high "weather tower" Also added a light sensor to it. If you want to check it out I made the sensor readings public at Thingspeak.

Cool isn't it? All the measurements are updated there every ten minutes. Also added one buffed measurement for the grow lights just to see that the logic works.

Programming challenge

One of the biggest programming problems I had was with the time. I heard from a friend that the Spark cores clock is shit and needs to be set on every loop. Now I had that in with punch of other changes so it took me quite some time to try to remove it and notice that it was the thing that killed the execution. Problem was that on every loop the Spark core restarted and this restart fucked up the whole execution. No sensor readings in Thingspeak. Restart was caused by this Particle.syncTime() function. I have it now only in the setup and not in the loop and all works nicely. Maybe if I put that in the back of the loop and it can do the restart as the last thing of the loop. I think if the time is a problem I will do that.

Now enough fiddling with the electronics

I need a grow something and this requires some work on the reservoir. The plastc box that I so far have taped with white ductape is going to act as a reservoir. Now the idea is to have the grow top be all rockwool sitting on some sort of frame that keeps it from sinking into the water. Also this frame would have handles so that I can lift the grow bed of the reservoir for maintenance and for changing the nutrient solution.

On the sides of the reservoir I used hot glue to put some plastic corners. Its just a cut from an L profile of plastic with 2cm per side. One piece on middle of each side of the reservoir.  I also put a tiny piece to each four corners of the reservoir to add support to the corners

The actual frame would be  an simple X shape. with some wire glued to each end as handles. First try was to use the same plastic L profile that I used on the sides of the reservoir. This turned out to be too flimsy as the wet rock-wool weights quite a bit. After a one hour test the plastic frame gave in and the rock-wool bed sank into the reservoir.

Next up was to go through my workshop to see what would be available. Found some aluminium L profile. Same size as the plastic one. I used the same principal as with the plastic except tried to make the center a bit more sturdy. Test is still running after 5h and grow bed has not yet sank 🙂

In short this grow bed assembly will be a challenge. I think it is still not sturdy enough. Sure it holds the empty grow bed but what when it actually has growing spinach on it? then need to move it up and down... Thing will need to be enhanced before any spinach can grow on the machine.

Added the rock-wool and nutrient solution. Sprinkled some Spinach seeds on top. Now its a wait game... Will they grow? Will they... 😀

Thats that for to day.

Still to do:

  • Fuses. For safety I need some fuses...
  • Grow bed frame needs to be made more sturdy.
  • Camera... Need to figure out how that works

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