This question is lying somewhere between electrical engineering and computer science, however I felt that this forum suited my question the best. I post this question because I feel that this kind of research is quite cumbersome if you don't look at the right places.

I want to mention that my question is not about buying goods, but rather where to search for information about the goods you want to buy, which I think is relevant to know for anyone who would like to build a smaller system on a chip. If there is a better forum for posting this question, please tell me.

I am planning to begin a project building a smaller system consisting of

1) 8-bit microprocessor

2) Some memory (speed is not relevant for my project)

2) Wireless communication unit (Wifi/Bluetooth)

3) Display (about a 2-3 square centimeters, only going to display some static images, and no advanced animations etc, resolution is not the big thing here).

4) Battery

I am not going to build every part of the system myself, and only the programming of the microprocessor will be the hard work from my side.

The thing is : want to make the power consumption of the system as small as possible (so that the battery last longer...), so my question is : How do I estimate the power consumption a system like this / where can i get that kind of information? Of course, the power consumption varies with what kind of components I am going to use, so what kinds of components suits best out of the energy saving perspective?

With the above specifications in mind, I express my first considerations about this below

Processor : The power consumption varies with the clock frequency and if you are giving it operations to perform, so what I am searching for is the average energy per clock cycle / average energy per operation.

Memory : What kind of memories are the most energy efficient?

Communication : Wifi / bluetooth best (read about Ericsson's new low power bluetooth technology, however I couldn't really conclude anything about the overall power consumption)

Display : What display's are the most energy efficient theese days? I have considered E-Ink displays as an effective alternative, but I'm not sure about this.

I am merely a beginner at this, so any input to the problem would be appreciated and if I am missing something here I would appreciate that kind of information aswell. Again, I am not asking for you to explicitly give me the answers to my problems, but where to effectively search for this kind of information. Of course some direct answer would not be wrong either.


  • \$\begingroup\$ Single design questions are required. \$\endgroup\$ – Leon Heller Nov 19 '14 at 17:39
  • 1
    \$\begingroup\$ Generally, use recent-generation low voltage technologies, and use them as little as possible - ie, not just reduced clock, but also putting the CPU to sleep, disabling peripherals, turning off the display when not needed, etc. Then look for power wasters such as signals driven against pulling resistors more than a tiny fraction of the time, linear regulators with a large voltage drop, regulators with high quiescent current, etc. \$\endgroup\$ – Chris Stratton Nov 19 '14 at 18:00

First work on your specifications.

An 8-bit microprocessor?? That is weird. Why the fix on 8-bit? And then, why a microprocessor and not a microcontroller?

memory: RAM? ROM? FLASH? How much?

display: what do you want to display? Can it be reflective or does it have to produce light? (for low requirements + reflective this is probably the least problematic part of your design).

communication: if this must be on all the time it is likely to dominate your power budget. Consider all alternatives, including simple transceivers and less-than-100%-on scenarios.

Battery: every design must have one 'free variable', this is likely yours.

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  • \$\begingroup\$ So before I begin cutting down my question here, isn't a micro controller just an embedded system consisting of processor + memory? Anyways, maybe that's what I'm looking for. The 8-bit can be changed, but doesn't the energy consumption increase with higher bit CPUs? Maybe that's not my biggest concern here, if it's all going to come down to the communication device. \$\endgroup\$ – skalet Nov 20 '14 at 17:55
  • \$\begingroup\$ A microprocessor is (just) a CPU on a chip, a microcontroller is CPU+memory+I/O on a chip. But better start with what functionality you need: X processing power, runing Y software, storing Z data. With such figures we can give an estimate of the chips needed. But unless you want to run a big system (Linux level) I think the wireless part will be your biggest power consumer. \$\endgroup\$ – Wouter van Ooijen Nov 20 '14 at 18:08

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