Maker Pro
Login Join Maker Pro
Or sign in with

Menu

Connect With Us

Network

Maker Pro

low power design and wifi

E

en2

Jan 1, 1970
0
Hi guys.
I need a suggestion regarding one project.
Well, the project should be one micro controller battery powered device
with wifi connection. Of course, the main problem is wifi and power
consumption.

Base processor will be ARM cortex M0 and the device should be powered
with 3,6V non rechargeable battery ( it's is not a must ).
WIFI range should be around 50 meter and it would be nice if i can hook
up external antenna.

Data will de send in half minute package and device should work 24/7.
Minimal work time of the device : 2 years.


I have found few ready made solutions like
- spark core ( over project budget )
- cc3000 ( TX power consumption 275mA )
- ultra low wifi ( small range )

Size of the device should be in 15x10 cm range so i can use some kind of
battery array but then again, this will be over project budget.

The main thing is to pass the data to Internet so some other solution
can be used.
 
A

amdx

Jan 1, 1970
0
I saw this but if i connect some USB wifi adapter i will end up in the
same situation as before or maybe worse.
I dont know, maybe am wrong...
Click to expand...

Only obvious thing I can add is high gain directional antennas to keep
the Wifi power down.

Mikek
 
E

en2

Jan 1, 1970
0
I wish there were a way to get two spdif jacks on them, and then use
them as comm links.

Then, one could daisy chain a bunch of them together and make a nice
emission free cluster.

But you could can the cluster and the router and use less power in the
links. But that is my cluster, not his scenario.
Click to expand...
------------------------------

So, the model with build in wifi costs 60$ without VAT and shipping.
End prize would be around $90 and that's quite expensive.

Raspberry has lower prize but 5W consumption so this is also out.

I have to use external antenna and it can be directional one so i have
to have some external jack to connect this antenna to.

It looks like that only option iw some built in wifi enabled device, but
i dont know if this can fit into budget range.

What about some ultra low power WIFI module ?
Maybe i can use this module with external antenna to get this 50 meter
range...
 
E

[email protected]

Jan 1, 1970
0
What about some ultra low power WIFI module ?
Click to expand...

It's a very common wish list (or wishful thinking), transmitting a few databytes over WiFi with battery device. But WiFi was not designed for low power. The connect/disconnect process is complicated and power consuming. The reasoning is that you save on the internet gateway, since WiFi routers are everywhere. Very often, the project get killed by the battery.

We use Asymmetric Network Transmission (ANT). The portable device TX at 30mA, but the gateway TX at 100mA. This is for a range of around 20 meters. For 50 meters, you probably need 200mA from the gateway. In between packets, the transmitters are off to save power.
 
E

en2

Jan 1, 1970
0
It's a very common wish list (or wishful thinking), transmitting a few
data bytes over WiFi with battery device.

But WiFi was not designed for low power. The connect/disconnect process
is complicated and power consuming.

The reasoning is that you save on the internet gateway, since WiFi
routers are everywhere. Very often, the project get killed by the battery.

We use Asymmetric Network Transmission (ANT). The portable device TX at
30mA, but the gateway TX at 100mA.

This is for a range of around 20 meters. For 50 meters, you probably
need 200mA from the gateway. In between packets, the transmitters are
off to save power.--------------
signing every word :)

I would "stop" transmission for half minute till i get full buffer.

ANT:
- can you share some link ?

What about other possibilities.
Some ISM FSK band transceiver.

So device would be some kind of basic ISM tranciever and it would not
have some big power consumption. On the other side, 50 meters away, i
can set some serial to IP converter. I know it's long shoot but..
 
H

hamilton

Jan 1, 1970
0
It's a very common wish list (or wishful thinking), transmitting a few
data bytes over WiFi with battery device.

But WiFi was not designed for low power. The connect/disconnect process
is complicated and power consuming.

The reasoning is that you save on the internet gateway, since WiFi
routers are everywhere. Very often, the project get killed by the battery.

We use Asymmetric Network Transmission (ANT). The portable device TX at
30mA, but the gateway TX at 100mA.

This is for a range of around 20 meters. For 50 meters, you probably
need 200mA from the gateway. In between packets, the transmitters are
off to save power.
Click to expand...

I think you are missing the point.

No matter how much data you send, you will need to connect to the router
every time.

The power use just to connect may be higher then the power to send the data.

The smaller the data packet the worse your power usage.

ANT:
- can you share some link ?

What about other possibilities.
Some ISM FSK band transceiver.
Click to expand...

There are lots of these type of devices.
TI has many to chose from, pick one and start from there.

http://www.ti.com/lsds/ti/wireless_connectivity/overview.page

Good Luck

PS: If you can find one of these on ebay:
https://dl.dropboxusercontent.com/u/74667085/star_trek_classic_communicator.jpg
 
E

en2

Jan 1, 1970
0
I think you are missing the point.

No matter how much data you send, you will need to connect to the router
every time.

The power use just to connect may be higher then the power to send the
data.

The smaller the data packet the worse your power usage.



There are lots of these type of devices.
TI has many to chose from, pick one and start from there.

http://www.ti.com/lsds/ti/wireless_connectivity/overview.page

Good Luck

PS: If you can find one of these on ebay:
https://dl.dropboxusercontent.com/u/74667085/star_trek_classic_communicator.jpg
Click to expand...
 
R

RobertMacy

Jan 1, 1970
0
I have to use external antenna and it can be directional one so i have
to have some external jack to connect this antenna to.

It looks like that only option iw some built in wifi enabled device, but
i dont know if this can fit into budget range.

What about some ultra low power WIFI module ?
Maybe i can use this module with external antenna to get this 50 meter
range...
Click to expand...

Interesting, the last product I did that had built-in Wifi: We could only
obtain compliance *IF* we tested the system WITH the proposed
fixed-connection antenna and if we needed to make a disconnect for the
antenna [which might inadvertantly enable a user to 'modify' our system],
we had to use a 'strange' RF connector, like one with left-handed threads
or such. Supposed to be unavailable to 'normal' consumers.

Has compliance changed?
 
E

[email protected]

Jan 1, 1970
0
It could take minutes to reconnect WiFi. You also have to enter the passcode in the device somehow.

Look up 802.15.4 without ZigBee. Ant is not Bee. Plus you have to actively manage power budget for the Radio and Processor. There are no magic module to do it for you.
 
K

Kevin McMurtrie

Jan 1, 1970
0
en2 <[email protected]> said:
Hi guys.
I need a suggestion regarding one project.
Well, the project should be one micro controller battery powered device
with wifi connection. Of course, the main problem is wifi and power
consumption.

Base processor will be ARM cortex M0 and the device should be powered
with 3,6V non rechargeable battery ( it's is not a must ).
WIFI range should be around 50 meter and it would be nice if i can hook
up external antenna.

Data will de send in half minute package and device should work 24/7.
Minimal work time of the device : 2 years.


I have found few ready made solutions like
- spark core ( over project budget )
- cc3000 ( TX power consumption 275mA )
- ultra low wifi ( small range )

Size of the device should be in 15x10 cm range so i can use some kind of
battery array but then again, this will be over project budget.

The main thing is to pass the data to Internet so some other solution
can be used.
Click to expand...

Power consumption is influenced by the WAP too. It needs to have
reasonable beacon and DTIM intervals, and enough buffering to not drop
packets while your radio is sleeping.
 
E

en2

Jan 1, 1970
0
Power consumption is influenced by the WAP too. It needs to have
reasonable beacon and DTIM intervals, and enough buffering to not drop
packets while your radio is sleeping.
Click to expand...
 
R

RobertMacy

Jan 1, 1970
0
...snip...
Interesting, the last product I did that had built-in Wifi: We could
only
obtain compliance *IF* we tested the system WITH the proposed
fixed-connection antenna and if we needed to make a disconnect for the
antenna [which might inadvertantly enable a user to 'modify' our
system],
we had to use a 'strange' RF connector, like one with left-handed
threads
or such. Supposed to be unavailable to 'normal' consumers.

Has compliance changed?
Click to expand...

These tiny boards have little tiny coax connectors on them.
Click to expand...

If it's that little 'button' type, I think I have the part number for that
connector, ...somewhere around here.

Doesn't this product have to meet compliance? Be tested as a system? It
is true that buying a module and sticking it into a system 'sometimes'
gains you automatic compliance meeting "intentional radiator" specs, but
not often. You still need to meet Class B "unintentional radiator" limits
and test for that. If you're lucky [or did it perfectly] with the addition
of the Wifi module; you won't have to test for the 'extra' radiation part,
which can easily be another $3k in test lab time. [from memory]

Check to make certain you comply with EVERY restriction listed in the
modules registration. If ONE item varies, you start over. Get each modules
documentation, that may also help in making your selection.

Footnote, if you place two like Wifi and zigbee in the same product you'll
probably end up with the two antennas closer than allowed in their
registration and you have to do the WHOLE testing series for compliance.
However, the FCC made a mistake on one of the zigbee modules and lists NO
restrictions on it being near another antenna. - major oversight! ah, but
the other one catches you.
 
E

[email protected]

Jan 1, 1970
0
No, It's ZigAnt. Yes, pay me $1 per year.

We have it on a 16K Atmega169, 64K PIC32MX130F064 client and a 512K PIC32MX675F512 server, which has 10M/100M ethernet.
 
E

[email protected]

Jan 1, 1970
0
WiFi vs 802.15.4

Not an Apples to Apples comparison.
Click to expand...

Yes, Bad (for OP's app) RF vs. Good RF.

OP did not require 801.11 only.
Are there any web pages that compare only WiFi models ?
Click to expand...

802.11 needs at least 500mW to operate and around 100 seconds to connect. Doesn't matter what models you pick.
 
H

hamilton

Jan 1, 1970
0
Yes, Bad (for OP's app) RF vs. Good RF.

OP did not require 801.11 only.


802.11 needs at least 500mW to operate and around 100 seconds to connect. Doesn't matter what models you pick.
Click to expand...

I am not a WiFi expert, but is that 100 seconds typical ?

I am sure, but I'll ask, does distance require more power or will the
router not accept the connection if power is too low ?
( or does it slow down )
 
You must log in or register to reply here.

Similar threads

N
Low power audio circuit design
Replies
10
Views
2K
Newtopprojects
N
stspringer
How to design a transistor circuit that controls low-power devices
2
Replies
30
Views
6K
Electro Bro
Electro Bro
Y
Low-Power Design Requires an Open, Comprehensive Standard: The Unified Power Format
Replies
1
Views
1K
Kevin Aylward
K
M
Low ESR Tantalum Failure due to Power On- Design Fix?
2
Replies
37
Views
3K
Ross Herbert
R
N
LOW power Design
Replies
2
Views
719
martin griffith
M
Top