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Forum Index : Microcontroller and PC projects : ElecFreaks cell-phone module...
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| Sir_M Newbie  Joined: 14/01/2013 Location: SwedenPosts: 15 |
Hi @ viscomjim Is this a board you developed and if not where to find it? Spended the last days searching like.... // J |
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| viscomjim Guru  Joined: 08/01/2014 Location: United StatesPosts: 925 |
@White, I am intrigued with your method. Power supply design, especially from batteries, is not really in my wheelhouse as of yet. Could you explain the going from 5v to 3.3v instead of from 12v to 3.3v. I was anticipating using a sealed lead acid 12v battery. Reason being, these are going on high end equipment trailers that apparently are in high demand for thieves. While connected to their pulling vehicles, they will have power from the vehicle that can charge them. They sometimes will be left at the destination site for weeks at a time and the sla battery is the only thing that will power them. Size is not much of an issue as they will be contained in a steel locked box, hence the external antennas. I appreciate any input you may have on this power situation. I will put things to sleep to save power, but the initial conversion needs to be extremely efficient, yet cost effective. @ Sir_M, this gsm module is from a forum member. His handle is Kiiid. HERE is a thread for this board. If you private message him, I am sure he will respond. This is a neat little unit as it has the gsm module AND the 170 uMite on the same small board. It has the footprint of an XBEE module, so not all uMite pins are available, but the more important ones are ie. both com ports, console com port, I2C port and a couple of IO pins. As I get more time on it, I will post some sample easy to use code to use this module. As it is relatively compatible with the elefreak sim900 module, the code will also work with that. This is also a great gsm modem board. HERE is a link to that one. |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 5905 |
I have used similar modules for 12V to 3.3V (and a few other In/Out levels. They work well and don't draw too much under no load. I would trust them to 2 amps but not much more when going from 12V+ to 3.3V Most of my uses do need 5V as well as 3.3 so I use a fixed, sealed 5V switcher and usually a standard low dropout 3.3V regulator. JIm VK7JH MMedit MMBasic Help |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1328 |
I've used several of these too Jim but mine cost $1.80 on e-Bay not the $8 that Amazon has them at. I'm currently using one that looks exactly like your suggestion, with the ESP2866 module and it's fine, both at 12v and 9v input (I tested both from my bench supply). There are dozens of variations of them available, even with little DVM's for <$4 - search e-Bay with LM2596, that's the chip used. The ones I have were quoted for a max. of 2A but as Tassy Jim says, that's probably stretching it a bit far. I did test them to 500mA though and at that they were fine - hardly got warm. Greg |
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kiiid Guru Joined: 11/05/2013 Location: United KingdomPosts: 671 |
Sir_M, the board is available now HERE http://rittle.org -------------- |
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