Thanks for the thought out response and suggestions Eric.
You’re right that using more basic materials such as C-channel (aluminum or steel) would be less expensive and more readily available. And we do want to lower the cost of the device and achieve widespread adoption. Though right now we want to have a flexible hardware system that is easy to work with and customizable for the DIYer/maker/hacker type folks - something that t-slot extrusions afford us more so than C-channel, strut, or angle iron would. That’s not to say that it can’t be done with those materials, it’s just that that’s not the route we took in our development because the first generation of devices are closer to 3D printers and CNC machines than they are to outdoor gardening/ag equipment.
But of course, anyone is welcome to build (and hopefully share) a FarmBot design with those materials. If they build it the same size as the devices we’re building then they could save up to $120 or so considering the total cost of all the extrusions in the current FarmBot design is about $150 (https://farmbot-genesis.readme.io/docs/extrusions). Perhaps there would be even more savings using regular rollers and belts too, on the order of $50 or $100. The benefits would be greater at larger scales!