Pir AS 312 with 2 rechargeable AAA battery. Boost needed?
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few month ago ,i use tlv61220 step-up boost only for as312 is only 4ua， atmega328p ,battery cr2477 , then get 21ua ,
but now ,i give up boost , i test use ER14335 3.6v CR16340LIPO 【4.2V with diode 0.7V Step-down then 3.5V+- 】 ，same as312 get 18ua,:relaxed: ,ER14335 cost much but 1600mah ！ cr16340 750mah rechargeable best choose for me,,,, -
Hi guys, project finished! Now the led are under the Fresnel lens, so the design of the case is more clean (WAF +10 :sunglasses: ).
The final result:
With 2 x AAA batteries and the RFM69 radio module the node works very well and the total cost of the parts is about 10€.
If someone is interested, here a detailed build guide, with the links to all the parts of the project (3d model of the case, Kicad project, gerber files, BOM, firmware).
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@franz-unix
This is wonderful work... thanks for inspiring me :-)
I know that this is an old thread,
but can you give me a link of the AAA battery holder please ?I just make a node sensor and I want to use it.
Thanks a lot
Denis@DenisJ : Glad to know that this work has been useful for you in some way. :+1:
Regarding the AAA battery holder, the footprints on the PCB are for a Keystone 5204 (negative) and Keystone 5226 (positive) contacts.
I have purchased them on ebay; unfortunately the item that I have purchased is not more available, but this one appears to me like the same thing.
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@DenisJ the link is broken, so I have not seen the contacts that you have bought, but if they are just a little bit smaller and they can fit the hole on the pcb, they should be OK.
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@franz-unix Hi, this post is very old I hope I can get an answer :)
I have ME2188 here but the behaviour of CE pin in extrange.
If I apply high to CE pin I get my correct 5v but if I change CE pin to low I get 4v on the output and I hope to get 0v.Anyone can share your experience?
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@franz-unix Hi, this post is very old I hope I can get an answer :)
I have ME2188 here but the behaviour of CE pin in extrange.
If I apply high to CE pin I get my correct 5v but if I change CE pin to low I get 4v on the output and I hope to get 0v.Anyone can share your experience?
@Diego-Serrano said in Pir AS 312 with 2 rechargeable AAA battery. Boost needed?:
@franz-unix Hi, this post is very old I hope I can get an answer :)
I have ME2188 here but the behaviour of CE pin in extrange.
If I apply high to CE pin I get my correct 5v but if I change CE pin to low I get 4v on the output and I hope to get 0v.Hello, this is the normal behavior for this chip. CE will enable the step up, but with CE low it acts as a bridge so you get input voltage at output.
Pretty annoying :)Anyone can share your experience?
My experience was to add an MT9700 power switch before the voltage input of the ME2188. The EN pin of the power switch is connected to the same signal than the CE pin of the MT2188, driven by the microcontroller.
It works fine like this driving a Plantower PM sensor not a PIR (don't pay too much attention at the caps at output I just wanted to have different footprints available).
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@Diego-Serrano said in Pir AS 312 with 2 rechargeable AAA battery. Boost needed?:
@franz-unix Hi, this post is very old I hope I can get an answer :)
I have ME2188 here but the behaviour of CE pin in extrange.
If I apply high to CE pin I get my correct 5v but if I change CE pin to low I get 4v on the output and I hope to get 0v.Hello, this is the normal behavior for this chip. CE will enable the step up, but with CE low it acts as a bridge so you get input voltage at output.
Pretty annoying :)Anyone can share your experience?
My experience was to add an MT9700 power switch before the voltage input of the ME2188. The EN pin of the power switch is connected to the same signal than the CE pin of the MT2188, driven by the microcontroller.
It works fine like this driving a Plantower PM sensor not a PIR (don't pay too much attention at the caps at output I just wanted to have different footprints available).@Nca78 said in Pir AS 312 with 2 rechargeable AAA battery. Boost needed?:
Pretty annoying
Thanks you very much.
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@nagelc The LiFePo4 batteries will be perfect (AA and AAA), but I arrived at your same conclusion: a little bit to exotic respect to standard alkaline or NiMH batteries.
@rozpruwacz Nice board, is similar to what I want, but unfortunately not exactly the same. I prefer to have one single board to simplify the build and external case design (3d-printable).
Thanks to your suggestion, I have modified a little bit the circuit:
Some consideration and board features:
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Added footprint for CR2032 coin cell and dedicated 100 uF capacitor to prevent problem related to the low discharge rate of the battery.
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Added a flyback diode across the inductor to discharge voltage spikes when the circuit is disconnected (mosfet Q3 - Pin D4). Not sure if it is strictly necessary... but just in case!
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Multiple power options: 2xAAA batteries, 1xCR2032, micro USB (phone charger), J6 pin header. When powered from an external source through USB port or J6, the voltage can be between 4 and 12V. When you power the board through FTDI or ICSP make sure that the voltage is 3.3V, otherwise the radio module will be damaged!
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Mosfet Q1 offers a reverse polarity protection to the board if the batteries are inserted in the wrong way. It cut off also the batteries compartment when an external power source is present, so you don't have to remove the batteries while powering the board via FTDI, ICSP, USB or J6
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When VCC is below 2.7V (AAA rechargeable batteries) the boost circuit is activated by the MCU (Pin D4). When VCC is above 2.7V (disposable AAA batteries or CR2032) the circuit is disabled and the PIR is powered directly form VCC (see Q3-Q4-Q5)
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To increase the battery life, the photoresistor is powered through PIN D5, only when the node is awake. During sleep D5 will be set to LOW, so no current waste.
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Two momentary switch: 1 for MCU reset and 1 to force the node to wake up
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Motion led (D3) and low battery / external powerl ed (D5) configurable in the firmware, plus radio activity LEDs
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Header for Si7021 breakout
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AS312 Pir with mounting holes for a standard fresnel lens like the one present in the HC-SR501
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MYSX 2.6 connector to add other sensors.
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ATSHA204A for security signing
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Size: 57x57 mm (not so small but also not so big)
This is how the board looks like
It is still under development, but if someone is interested, the Kicad project is available on github.
... Well the next step is to test the ME2188 boost converter... I hope that it can do its job without triggering false positive on the PIR sensors!
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