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Very basic questions on the MSP430 Solar Energy Harvesting Development Tool

Thaddaeus Voss
Prodigy 20 points

I have no idea if this is the right place for a question like this, but I was directed here four times, so if someone wants to redirect me that is fine...

I have a few questions about the MSP430 Solar Energy Harvesting Development Tool. I have not purchased this kit yet, however, I am very seriously thinking about it. First, to explain my situation, I will give you a little background. About a month ago, I ordered the XLP 16-bit Energy Harvesting Kit from Microchip (http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2042¶m=en548091). This actually seems very similar to this development kit (it even also includes the CBC-SEH-01 board from Cymbet), it just does not wirelessly transmit data. However, I have a HUGE problem with this kit, and am pretty disappointed in the kit, because while it claims to give progress on the charge percentage of the board, it does not accurately do so AT ALL. Therefore, if I purchase this kit, I would like to be assured that it is in fact able to transmit the charge percentage of the EnerChip batteries, and that that charge percentage will be totally accurate and in real time. Can anyone confirm this? Also, could anyone give me some insight as to what program is used and exactly what data is transmitted to the PC? Microchip had a video that showed the program output. It would be nice to have a description of exactly what data is shown when the kit wirelessly transmits data to a computer. Additionally, since I already have the CBC-SEH-01 board, can I just purchase two eZ430-RF2500T wireless target boards and the debugging tool separately? I would not like to buy the kit since I already have the CBC-SEH-01 board. I want to buy all the parts separately to make this kit work as it should. Lastly, how much power does it take to wireless transmit the data each transmission? I would like to see how fast different transducers can charge the batteries, however, if it takes too much power from the transducer/battery to transmit data, I would not get a very accurate reading overall.

Thank you for any help you can provide!

  • 0
    Guru 227245 points

    I don't have any experience with this kit myself, but from general experience...

    If you go to the product page of the kit, you  should find links to related documents, including layouts, demo codes etc. At least it is this way for most if not all MSP-related products.
    You can look into the code for details. Or maybe there's even a written documentation.

    Thaddaeus Voss said:
    Additionally, since I already have the CBC-SEH-01 board, can I just purchase two eZ430-RF2500T wireless target boards and the debugging tool separately?

    The target boards and the debugging tool are available separately. if the other board is indeed the same, then you should be able to just the missing parts.

    About the charge accuracy, well, battery charge metering is a tricky thing. Only after you depelted the battery, you know how much was in it. Under ideal circumstances you may guess that next time you filled it, it will hold the same charge again. But with energy harvesting, you have many charge cycles and charge and discharge intermixed, so all information about the current charge is only a guess at best.

    A typical way to check the current charge percentage is to expose th ebattery to a define dload and check the battery voltage before and after. However, in case of energy harvesting, this is a bad idea (way to much energy wasted). Just measuring the current battrery voltage gives no information of any worth - after some time of no current draw, the battery voltage may be as high as if it were full, where it is in fact almost depleted. To freely cite Heisenberg: "you may exactly know the charge or use it, but not both"

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