Probably the easiest way to make this would be to procure all the parts in the parts list below, and send off all the necessary files to your favourite PCB manufacturer. If you live in a big city you can likely get all these parts locally. If you live in North America, you can order everything from Digikey. I've given their part numbers for everything and provided a link to an online B.O.M (Bill of materials). If you download and extract the archive file mmmse_all, inside you'll find all the silkscreens, gerber files etc. you should need for PCB fabrication zipped up together as "mmmse_alpha-0.1.1_pcb_manu_files.zip." When I made my boards, this was the file I sent to APC (Alberta Printed Circuits) in Calgary. There are lots of other places all over the world that may be cheaper, but I used APC because they are in Canada and have great service. You might need to send other stuff for other board manufacturing houses, but you'll have to research that on your own. I made a board like this because I wanted to make a whole bunch of them. This circuit is easily breadboard-able or solder-able on a PC board if you just want to try out one or two. Making Your Own Modifications There are many software programmes for designing boards out there. I used Kicad because it is free and is for Linux. There is also a free Windows version available. You should be able to yum or apt-get Kicad for your Linux distro, or get the source (or exe for Windows) at the Kicad website. There is also a helpful tutorial floating around, links below. If you want to make changes to this circuit with Kicad, I've provided all the project files and also my own custom libraries for schematic symbols and component footprints. They are all in the "mmmse_all" archive. See the read_me text file in there for more details. Parts List see http://octopart.com/partlist/view?id=NDYyOTQ5 for a parts list. LABEL / DESCRIPTION / DIGIKEY PART # IC and semiconductors: U1 / Maxim 8212 voltage monitor / MAX8212CPA+-ND Capacitors: C1,C5 / .01uF capacitor / BC1095CT-ND Resistors: R1 / 1K resistor, 1/4 watt, 5% / 1.0KQBK-ND Connectors: P2,P3 / 5mm green 4 position terminal block / 277-1609-ND Known Errors, Needs Work: 1. in the board files, there's no connector P1... only P2 and P3 Sinks and Sources In this case what I mean by "source" is the combination of charging device and storage device. By "sink" I refer to whatever it is you are turning off and on. In the Canoe (Solar Version) the source devices were 2 flexible 13.5 watt solar panels I got from Canadian Tire and twelve 50F 2.5 volt super caps I found at Digikey, and yes that is Farads. The caps were connected in two parallel series of 6 caps so they would be able to withstand up to 15 volts. The sink device was a gear motor driving the paddle. In the Stepper Motor Choir the sources were also super capacitors and solar panels. The super capacitors were 360F at 2.7 volts connected in a series of 5, to withstand up to 13.5 volts. The solar panels were custom made with cells ordered from Plastecs.com. Each panel had 25 cells connected in series. The cells were specified as .5 volts at 1.75 amp each, for a theoretical total of 12.5 volt, ca. 22 watts per panel. This never really happened of course. The sink device was a micro-controller board driving the stepper motors. It's beyond the scope of this article to describe all this in more technical detail, but if you use super caps you should solder 10K to 22K resistors in parallel with each cap. This helps balance the charge on each cap in the series. I used solar panels and super caps, but there is no reason why this circuit wouldn't work with other sources: wind, piezoelectric, bicycle dynamo, SLA batteries for storage etc. This is what I'm currently experimenting with. The combination of source and sink devices is pretty wide open to imagination and experimentation. Hopefully someone out there will find interesting uses for this circuit. Let me know if you do, and please pass on any and all suggestions, corrections, comments or criticisms Links http://octopart.com/partlist/view?id=NDYyOTQ5 - Bill Of Materials at Octopart |
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