Electric Imp & Batteries

Wow, this post has questions I asked almost a year ago! The things I have learned while deving with the Electric Imp!

It’s now May 2014. I see from imp 001specification version 20140226 that for wifi use, a minimum of 2.5V is needed at the imp Vdd pin. Am I reading this right, that imp will work normally and connect to wifi and run device code at Vdd = 2.5V?

Thats correct. You only need 1.8 to run device user code, but you need 2.5 to start WiFi.

No, the 2.7V figure Hugo posted upthread was correct. The forthcoming imp003 module, though, will work down to 2.5V.

Existing imp001s and imp002s might appear to work below 2.7V – but operation, particularly firmware-upgrade operation, is not guaranteed.

Peter

Is that 2.7V at the input of the april board, or 2.7V at the Vdd pin of the imp 001?

I run my imp001 directly from batteries and I have one still working at 2.4v as reported by hardware.voltage() :slight_smile:

The quoted limits do appear to be quite conservative. It really depends on how you feel about “this one here seems to work” as opposed to “this is what’s guaranteed by the chip manufacturer”.

It’s 2.7V at the Vdd pin of the imp001.

Peter

Ahh… 2.5 is still in the datasheet…

Hi Peter,
thanks for the info. I’m just trying to make sure that my imp has the correct voltage to both connect to wifi AND execute agent code. I’m still at the early learning stages with the imp so my questions are all based on lack of knowledge. I was not sure if 2.7 was at the april board + and - or at the imp 001 Vdd pin, hence my question. The imp 001 spec version 20140226 says 2.5 at the Vdd pin. If it’s 2.7 at the Vdd pin that’s okay by me and I’ll make sure I cater for that in my design.

thanks,
P.

If you are using April, you will want to supply 3.6V or more, since the April has a buck convertor on board.

Thanks MakeDeck. But what if I am not using the april and am supplying the imp 001 direct. In that case what is the minimum voltage at Vdd to get to imp to connect to wifi AND execute device code AND update imp flash (if needed, since I had not thought of this before).

Imp 001 spec version 20140226 says 2.5V at the Vdd pin of the imp. I just want to check that my understanding is correct i.e. if 2.5 is minimum for above wifi AND exec exec device code AND reflash requirements. If it’s not and imp needs 2.7, thats okay. I just want to know if its 2.5 or 2.7 (at the Vdd pin of the imp 001). I don’t know what version of imp 001 I have, only that I bought it 2 weeks ago. I know 0.2V between 2.5V Vdd and 2.7V Vdd appears minimal but just want to know my design is within spec.

Any insight or practical experience gratefully accepted :slight_smile:
P.

I should have said, thanks MakeDeck for the info about the 3.6 V. If you or any of the forum members have experience of supplying the imp direct without the april board it would be very helpful. I just want to clarify if 2.5 at the Vdd pin of the imp (as per the spec) is correct or not. If it’s not that okay, as long as I can find out what the correct value is :slight_smile:

P.

I designed P3V3 and C3V0 around the reference designs, and they are a great place to look. P3V3 uses a 3.3V regulator and C3V0 uses a 3.0V regulator to maximize the power of a LiPo battery. I haven’t built a design yet that uses a lower voltage, so I am just quoting the datasheet.