EG's Ventilator 3000, part 1

Megan Wagner and Cori Gilkey - welcome, and thanks for following the blog!

I want to thank Karen for the nice email she sent me yesterday. It was really nice to hear from an heirloom tomato gardener from my neck of the woods. :-)

The other day I mentioned that something would be constructed to open the coldframes automatically when the temperature inside gets too hot for the plants' liking. Since you can purchase something from the internet for around $50 that will accomplish this task for you, I decided to construct something that would be cheaper. Immediately, 3 different ideas came to mind that would certainly work well, but only 1 option was even in the ballpark when it came to being under the $50 threshold. This project will be in 2 posts, because i'd really like to share alot of detail in the construction of it. My inventions/ideas are usually very unique, and evolve from a need to accomplish a task in a way that it will somehow make my gardening experience better. The biggest problem is, usually there's nothing on the internet to use as a reference (because it hasn't been built by anyone yet), so i'm just on my own to come up with an idea on how to construct it.

Anyway, I had this old 12 volt cordless drill laying around that had a bad battery, but the motor itself was in pretty good shape. The only downfall is that the gearing/clutch in the chuck assembly is quite noisy when running. Still, it's got quite a bit of torque for turning something, and i'm gonna use it to open the window in one of my coldframes - (thermostatically, of course) Hehe....The force needed to lift the side of the hinged window seems to be less than a couple of pounds - so it shouldn't have a problem with this. Now, it's time to resurrect the previously useless item in the photo below - which has been laying dormant in it's case for about 5 years now.....

Ok, i'll explain things along the way so that you will hopefully understand what i'm talking about.....
The trigger and switch inside the handle is useless for this project, but the motor itself (at the top) needs to be supported by something. So, the motor is removed from the plastic housing for a little bit of modification - then will be re-assembled once again. The switch and trigger are removed and discarded.....

Photo below - here's the motor and chuck assembly. See the 5 different wires that are attached to the rear? Well, we only need the 2 wires that are attached to the brush holders. For reference, this is simply a dc motor that has a permanent magnet for supplying the magnetic field that the rotating member turns in. If the polarity of the supply voltage is reversed when connected to the armature, it will turn in the opposite direction. Oh, you can bet that i've already got a plan together for how it will be reversed automatically for this project.

Photo below - With all of the unnecessary wires removed, this motor is ready to be put back into the plastic housing that it's supported by. A 4 foot piece of lamp electrical cord is connected to the ends of these 2 wires, which is only used to extend them outside of the plastic housing.

Photo below - Here's what will be used to reverse the motor for me. It's an ice cube relay plugged into it's mounting base, that has a 24 volt dc coil in it for making/breaking the 2 sets of contacts inside. (DPDT, or double pole double throw). I'm a little bit concerned with the minimal amount of gap between it's contacts, and may opt for a completely different kind of relay that has a gap that is much wider. Hmm...now that I think about it, I could use 2 of them in parallel to seperate the 2 polarity transitions.....That's what i'll do...

Photo below - Ok, I know the initial thought from seeing the modified drill strapped to the inside of the coldframe is probably "what the????". Well, it had to be this way, and is certainly mounted very rigid by the plumber's strap. A piece of 5/16" allthread rod is placed in the drill chuck that will be used to transmit torque from the motor to accomplish the needed task. I guess this would certainly qualify for the "you might be a redneck" list by Jeff Foxworthy. Ha! While inserting the allthread rod in the chuck with the help of a 12 vdc electric wheelchair battery connected to it, I thought the thing was gonna rip my hand off. I couldn't hold it, because the amount of dc current supplied by the unconventional battery is impressive! Under the right circumstances, this drill is unbelievably strong. I'd put it up against a new 18.8 volt drill anyday, as long as I could use the wheelchair battery connected to this one. Hehe...It's impressive...

Photo below - This right angle bracket was leftover from a previous construction project, and is just the thing needed to create the unit that will run on the 5/16" allthread rod. It was cut into 2 pieces with a hacksaw, then had 2 holes drilled through them for the bolts to go through. I'll also cut the short end of the "L" off, because it won't be needed.

Well, I think that's gonna do it for part 1. Part 2 will be posted about once I get the remaining work on it completed. So far, everything that has been used was already on hand (there's all kinds of crazy things laying around here), but i'll have to invest about $7 on a couple of things later. No big deal...Anyway, i'm sure that this project will be right up there with some of the craziest things that's been built by myself over the last few years, but hey! They always work, don't they? Hehe....BTW, the only power tool that is being used is my "good" cordless drill, because welding the pieces would be an advantage that most people don't have at home. I like to keep things simple, and don't have a shop, vise, or drill press. I just make do with what I have on hand - kinda like MacGuyver. Anyway, i'll try to get the rest of the stuff together hopefully this weekend, and do the final post about it then. After that, i'll shoot a video of it in action. My personal feeling is that without a video of it actually working, then it never happened. Stay tuned for part 2.......

Take care, and happy gardening  building!

EG