A little update to show the Redshiftt main receiver/relay box taking shape. This actually reached this state months ago, but under the present challenges we’re all struggling with I kinda back-burnered Redshiftt in favor of keeping Vanistan prosperous. I’m also pretty lazy about posting (mostly because I really struggle with this site software). But I know folks that are excited to see how it’s coming along.
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So, here’s a few pictures of the main receiver/relay box. The first shows a rough-looking cover prototyped with my 3D printer. Don’t worry, the actual covers won’t look like this awful thing. You can see it was printed in two halves and glued together, that was the best way to do it. 3D printing surely looks like crap, but it’s handy for knocking something out, as long as you need it tomorrow. In actual production the covers will be thermoformed clear plastic (see my previous post on the box design). But I needed a cover made to the design to test the fit and sealing, so 3D printer to the rescue. And it’s gonna work nice!
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Inside, there are six 30-amp single-pole dual-throw (SPDT) heavy-duty automotive grade relays, the Bluetooth module which controls them, a separate fuse for each relay, and a 12-circuit lug block where connections can be made in addition to the 3-lug connectors at each relay.
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I built these prototypes in my shop in mild steel sheet, in production they will be laser-cut stainless, so the edges and holes will be neater than my handiwork. I also need to perfect fitting the EPDM foam strips that seal the top over the endwalls and provide wire entry sealing and strain relief along both long sides, you can see they’re not as tight a fit at the ends as they’ll need to be.
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My open-framework approach keeps cost low but also allows maximum wiring flexibility for all possible applications. Each relay has a 12ga. wire from it’s common pole to one fuse, and from the fuse to the lug block. All other connections are made according to the user’s circuit designs. Unlike most similar products which only switch power from a single positive battery bus, an open framework allows switching either the positive or negative side of a load circuit, because many applications are best done on the grounded side. You can also source positive power from switched supplies, such as the ignition-on or lighting circuits, or route a grounding circuit thru another grounding switch elsewhere, all of which let you impose an additional condition on operation of that circuit. Being SPDT, your loads can be connected to the Normally Open (NO) or the Normally Closed (NC) pole of a relay, you could use a relay to alternate between two loads if desired, or the fused connector can be moved to either pole from the common as well. You basically have choices in wiring design that similar accessory control boxes simply won’t allow.
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Some similar products use separate weatherproof automotive connectors on pigtails emerging from the control box. That approach has some real disadvantages. First is cost: quality weatherproof automotive connectors are expensive and the user has to also buy premade proprietary harnesses with the mating connectors. The harnesses might not be long enough for some applications, necessitating extension harnesses or other additional connections to extend them, and when they’re too long, you’ve paid for a lot of wasted wire. The wire gauge may be too big, which is just a waste of copper, or too small to power the intended load without adding another load relay. If you want to change things later you may have to buy more proprietary harnesses. And as to circuit quality, more connections, no matter how good they are built at first, means more places resistance can creep into a circuit from corrosion and mechanical weakening of connectors. Basically, as any electrician will confirm, the best electrical design uses as long uninterrupted wire runs of the appropriate gauge for the current requirement with as few connections as possible. By offering an open framework, you can do the best possible wiring job using whatever wire type and size is best for the application with just as long a continuous wire as needed and the no intermediate connections. It also keeps the price low for the control box, as well as your own costs for wire and connectors. And by using lugs, you only have to strip the wire end to connect inside the box, although if you’re really into a good job you’ll tin the stripped end with solder first.
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Not everyone will need so many high-amp relays, of course, but all six being 30-amp is a by-product of another approach I’ve used to keep the cost low: I only have to produce one printed circuit board with two relays on it, which is designed to be connected edge to edge to build out to six relays. Only one of the three boards is populated with the Bluetooth module and supporting components, the other two PCB’s just support the relays and switching transistors which get their control signals from the main board.
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This allows me to keep my development and production costs as low as possible. The downside is this box is not as compact as some of the similar products, but it’s not that much bigger, and in return it will come in at a pleasingly lower price. I’m not willing to talk actual pricing yet, but I’m on track to come in much lower than any competitive control box product with a package that will include the Redshiftt wireless gearshift knob controller, the only one that literally puts control in the palm of your hand.