Ultra Low Power Stick, Is There a Market?
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I was wondering if many users would want a stick that can run off battery power in a low power mode for perhaps a week, like a cell phone can...
(I just demonstrated the M5stickC to a user group, with 5 different apps merged into one, had to worry about having LCD backlight turned down to get more than 20 minutes battery life)
This may require some improvement of peripheral power management and an E-Paper display, which can be 'on' all the time (but with severe limits to interactivity) may need to rely on USB connection for setting up WiFi connection, etc, or an attached OLED "terminal" for basic setup interface in the field (a screen mirror mode would be fun)
Applications that come to mind include:
- Environmental readings display that updates Temperature, etc readings once per minute.
- Bitcoin price display that updates from the web every 15 minutes.
- Data logger that stores low volume data in ram, and transmits hourly packets via WiFi.
- Should be able to run as a BLE beacon for a reasonable amount of time.
There's one E-Paper display prospect that may be suitable.
http://www.e-paper-display.com/products_detail/productId=412.html
GooDisplay 1.02 inch Flexible E-Paper Screen : 128x80 resolution, B&W part# GDEW0102I4F
Outline: 32.57 x 18.6 x0 .3mm, Active Area: 21.76 x 14mm
Some tricky folding of the connector end would be needed,
the 0°C~50°C operating range is an issue as well.(Alibaba has considerably lower price offerings)
To counter the large visual feedback delays of E-paper, more inputs, like 5 touch sensor hot spots embedded in the case along 1 edge of the display would be useful for menu designs.
Even the ideal ESP32 hardware is a challenge to run from an 80mah battery. The work done on stick watch software should be very helpful.
I understand that the overhead to wake from a deeps sleep makes it only practical to sleep for more than 1 minute at a time.
The 200mA overhead of running the radio, would probably limit connections to very short bursts.
This example post concluding that 20-25mA is required to maintain an AP association, is the sort of ESP32 issue that may be quite challenging.
https://esp32.com/viewtopic.php?t=8070One E-paper article noted:
“an e-paper display will use around 3 mA for 2 seconds each time it updates its contents” -
It would be a good project but would result in a completely different product. For greatly extending the run time of the existing product how about a large external battery such as a power bank connected to the usb jack? Quick, cheap, and easy and should do fine for demonstrations and prototyping.
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I would really like to have an M5stack with e-paper display! I do have one of the use cases you mentioned - bitcoin price ticker, but I'm not using M5Stack due to several limitations, the biggest of which is that the display cannot stay ON while device is sleeping.
If anyone develops an M5stack with e-paper display (and eliminates the above limitation), I will gladly buy large quantities of this device!
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@m5er said in Ultra Low Power Stick, Is There a Market?:
I would really like to have an M5stack with e-paper display! I do have one of the use cases you mentioned - bitcoin price ticker, but I'm not using M5Stack due to several limitations, the biggest of which is that the display cannot stay ON while device is sleeping.
If anyone develops an M5stack with e-paper display (and eliminates the above limitation), I will gladly buy large quantities of this device!
Does a epaper display exist that is small enough?
As the default firmware is micropython based then it may be possible to swap out the SPI screen for an eink screen.
And yes there is a market for a more energy efficient version. -
HI,
what about this idea:
wake
connect to wifi
display to 100
read light sensor
ping m5stack.com
wait 5 sec
display go down to 30
deepsleep 10 sec.all is native base on latest m5stack uiflow. only the ping is extra lib imported and bit modded.
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Hey @ajb2k3, thanks for your input, but I'm afraid bigger/external battery doesn't answer OP's question and neither the issue I referenced. An e-paper display will certainly render the M5stack a lot more energy efficient while preserving the same product size (while external battery will just make the product bigger). And yes, e-papers of this size do exist, though are probably more expensive than the OLED.
@Mati if your M5stick is indeed in deep sleep while the display is on, then the issue I referenced earlier affects only the M5stack. I don't see why this issue is not fixed in this product...
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@m5er let my try to kill the lcd in deepsleep.
Keep in mind i have other project with pure esp32 chip and small oled, and guess what =] lcd is also not cutted do the code design. Power is still drained from esp module.There must be the way to cut it and now i will follos this for sure =D
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Hey @mati. Any success on this?
Just to be clear, the issue is not that I need to cut the LCD in deep sleep, but just the opposite - to keep the LCD ON while the M5Stack is in deep sleep. Have you managed to test this? -
@mati said in Ultra Low Power Stick, Is There a Market?:
HI,
what about this idea:
wake
connect to wifi
display to 100
read light sensor
ping m5stack.com
wait 5 sec
display go down to 30
deepsleep 10 sec.all is native base on latest m5stack uiflow. only the ping is extra lib imported and bit modded.
When you say "all is native base on latest m5stack uiflow" do you mean the uiflow firmware or the Blockly blocks? Because I don't see a block for deep sleep in uiFlow. I'm interested in getting deep sleep working with uiFlow.
