David,
I have no experience with batteries, so I can't say anything about the problem you have mentioned. But it just means the emptying out process is not linear. But, if you will perform the test I have suggested several times, and you will see the results are consistent, you can build a converting table. Perhaps you can even measure the RSSI to help you doing that (I guess the RSSI will decrease as the battery decreases). Arik _____ From: David Conde [mailto:[email protected]] Sent: Tuesday, October 27, 2009 13:19 To: 'Arik'; 'Nicola Bressan' Cc: [email protected] Subject: RE: [Tinyos-help] Battery Level for Telosb Hi Arik, It looks like a good idea. The only problem it is that I have read that these kind of batteries can fell down to 0% batterys level from high Voltage level, I mean, these batteries can sometimes fell down around 0% of batterys level with for example 15 Volts and sometimes fell down quickly from 25 Volts, at least this is what I read about. Do you know anything about this? Anyway, thanks very much for your answer, I will use this method if nobody say something about the problem which I have talked about before. Regards David De: Arik [mailto:[email protected]] Enviado el: martes, 27 de octubre de 2009 12:05 Para: 'David Conde'; 'Nicola Bressan' CC: [email protected] Asunto: RE: [Tinyos-help] Battery Level for Telosb Hi David, I have a suggestion: Step 1: connect a mote to a USB and check the current voltage. This is 100%. Step 2: connect to batteries. Make a program that sends the current voltage all the time. Besides that, add some computation, LEDs blinking and send as much messages as you can - to decrease the battery life. This way, when the battery dies you will stop receiving the current voltage values. Then check the last value you have received this is 0%. Now you can calculate the desired percentage :-) Good luck, Arik _____ From: [email protected] [mailto:[email protected]] On Behalf Of David Conde Sent: Tuesday, October 27, 2009 12:41 To: 'Nicola Bressan' Cc: [email protected] Subject: Re: [Tinyos-help] Battery Level for Telosb No it is ok, you helped my telling me about the InternalVoltage component, just I wondered if there is a relation between level battery to Voltage level because I do not know if there is some relation between them? The problem is that I am going to use it for critical systems which never can stop because of battery off, for this reason I need something which warns me that battery is going to be finished completly, before that the battery is actually OFF (0% of its level).I would like to have something which warns me when the batterys level is around 10% of its 100% level. Thanks in advance and thank Nicola for your answer Regards David De: Nicola Bressan [mailto:[email protected]] Enviado el: martes, 27 de octubre de 2009 11:23 Para: David Conde Asunto: Re: [Tinyos-help] Battery Level for Telosb I'm sorry but I don't succeed in answering to your questions because I'm not never me place the problem... I don't have more experience about this... I have confined to effect a periodic reading of the data.... Sorry if I don't help you.... Nicola 2009/10/27 David Conde <[email protected]> Hi Nicola, Thank you for your answer. Do you mean that you use Msp430InternalVoltageC in order to get the level battery?But what is the function which relates battery level to voltage level from InternalVoltageC? For example, do you know what voltage from InternalVoltageC is equivalent to 10 % of full battery? I read about use InternalVoltage and people said that is not very reliable, because of level battery usually falls down much more faster as Internal Voltage does, so from your experience, do you usually use it in order to get a threshold for mínimum battery level, dont you?What is the voltage do you use as mínimum battery level? Thank you in advance David De: Nicola Bressan [mailto:[email protected]] Enviado el: martes, 27 de octubre de 2009 11:02 Para: David Conde Asunto: Re: [Tinyos-help] Battery Level for Telosb You can see the component Msp430InternalVoltageC(). I use this for read the Voltage/Battery Level and I think that is the correct value becouse i see that, when I use the battery the voltage is 2.5V but if I use the cable-USB the voltage is 2.97V Nicola 2009/10/27 David Conde <[email protected]> Hi, I have read some information in TinyOS-help about how getting battery level from VoltageC components in Telosb, but I think there is not direct relation between the Voltage Level in TElosb and Battery level, I am sure that someone else has had the same need of getting the battery level in order to send an alarm message so batteries in Telosb can be swicthed each time that they are almost finish. How could I solve this problem?If there is no way to get the battery level from Telosb, how can I work around about this?Does it exist any sensor which can be integrated in Telosb to get the battery level as the same way as a mobile phone does it?Does it exist any electronic circuit to get the battery level? I am working with TinyOS 1.x and Telosb motes Thank you in advance _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
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