Supplemental Battery Powered Light - Wireless Activation with 120v Wall Switch

Projects General Guidance
1

I'm thinking through what it would take to create a device which can switch a relay to turn on battery powered lighting, and activate when a 120v wall switch is turned on.

As an example ... in our laundry room, I'd like to put some battery powered lighting under a coupe of cabinets, and have them switch on when the ceiling light fixture is turned on with the wall switch.

I'm comfortable with the overall premise, meaning the code and switching hardware needed for each side (like sensing the 120v on the switch, as well as activating a relay on the battery powered light, etc) ...

What I need some help with is choosing a suitable wireless module for each side. I need something small enough to fit inside a single gang switch box, which can communicate wireless to the receiver(s) on the battery light(s).

I've been using ESP8266 ESP-01 modules for other projects, and thought this may be a good choice .. but the pin breakout on them is really limited and may cause a challenge.

Is there a small bluetooth module with an integrated microcontroller (like the ESP-01 for WiFi) which would work well here?

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2

Why not have a light sensor attached to the relay for the battery powered light? It should be pretty easy to tell the difference in light level with the lights on vs. off. No wireless communication required

3

The big problem here is common to all remote control devices where the receiver is not mains powered. Wireless (or infra-red) receivers require continuous power to operate, so if they are battery powered, the battery lifetime is significantly limited. If you have a wireless doorbell where the bell itself is battery powered, expect the bell unit to require battery replacement - even using alkaline "C" cells - every three months at least and you may not realise when the battery goes flat.

This is not an Arduino project. The receiver modules available are intended for data transfer, not low-power standby operation (at least, not if you need them to be actively monitoring).

You need to look for a remote control transmitter and receiver module set which is specified for extremely low power consumption of the receiver. But in the long run, I think you will be quite disappointed.

4

blh64:
Why not have a light sensor attached to the relay for the battery powered light? It should be pretty easy to tell the difference in light level with the lights on vs. off. No wireless communication required

I had actually started playing around with a circuit to do exactly this yesterday, right after I posted this. Just a small photoresistor, a 9v battery, and a 3v relay. I think this will probably be what I end up with, as it's quick and easy ... thanks!

Paul__B:
The big problem here is common to all remote control devices where the receiver is not mains powered. Wireless (or infra-red) receivers require continuous power to operate, so if they are battery powered, the battery lifetime is significantly limited. If you have a wireless doorbell where the bell itself is battery powered, expect the bell unit to require battery replacement - even using alkaline "C" cells - every three months at least and you may not realise when the battery goes flat.

This is not an Arduino project. The receiver modules available are intended for data transfer, not low-power standby operation (at least, not if you need them to be actively monitoring).

You need to look for a remote control transmitter and receiver module set which is specified for extremely low power consumption of the receiver. But in the long run, I think you will be quite disappointed.

I've seen some extremely low power consumption projects, using things like an ESP8266, where wireless battery life was quite long. To your point though, in most of these projects it was the transmitter running on battery, not the receiver.

It seems in a "Light Sleep" mode, the ESP8266 will consume 0.5mA ... so with 2400mAh AA batteries, this would be around 200 days of battery life. So battery replacement about every 6 months or so.

My initial thought was the receiver device battery just for the receiver and switching mechanism itself. An opticoupler would be less mAh to hold open than a relay would as well.

5

Stoopalini:
It seems in a "Light Sleep" mode, the ESP8266 will consume 0.5mA ... so with 2400mAh AA batteries, this would be around 200 days of battery life. So battery replacement about every 6 months or so.

Fine, but this has nothing whatsoever to do with your project. :astonished:

An ESP8266 in sleep mode (any sleep mode) is doing nothing. Specifically, it is not listening for any communications at all.

When I focus (difficult) on the task, I need to make a number of "the Button" devices using an improvement on the circuit employing the Power Down function of the ESP-01. This will allow it to lie dormant until the button is pressed and then continue operating until it has sent its message and had it acknowledged. This is of course perfectly practical for the sending device, but the receiver must be mains powered to be always active.

6

Paul__B:
Fine, but this has nothing whatsoever to do with your project. :astonished:

An ESP8266 in sleep mode (any sleep mode) is doing nothing. Specifically, it is not listening for any communications at all.

When I focus (difficult) on the task, I need to make a number of "the Button" devices using an improvement on the circuit employing the Power Down function of the ESP-01. This will allow it to lie dormant until the button is pressed and then continue operating until it has sent its message and had it acknowledged. This is of course perfectly practical for the sending device, but the receiver must be mains powered to be always active.

This made me think it can be woken from Light Sleep mode with a wireless WoL data packet. Maybe I'm mistaken ... certainly possible since I'm trying to learn more about it here .... ::slight_smile:

https://bbs.espressif.com/viewtopic.php?t=133:
There are a few things need to pay attention to.

*You can use wifi_set_sleep_type to set sleep type for power saving and set NONE_SLEEP_T to disable power saving.

*power saving modes can only be enabled in station mode, since ESP8266 do not sleep when working in softap mode.

*Wake up of sleep:

Deep Sleep: ESP8266 need be waked up by xpd_dcdc(Pin8) or by other gpio of external MCU. Thus, xpd_dcdc(Pin8) or external GPIO should be connected to ext_rstb(Pin32).

Light Sleep and Modem sleep:Both are automatically added by underlying, which can sleep and be waked up automatically. There is no need of any processing in hardware.

*About test data:

Light Sleep and Modem Sleep:Both can adjust themselves to support the type of DTIM according to the AP that connected. Thus, the above data of power consumption in DTIM1 and DTIM3 is just calculated.

Deep sleep: There is a parameter(108th byte) for the interval of RF cal in the esp_init_data_default.bin as is shown below. Currently, you can set the interval of RF cal by modifying the value of this parameter. Then,you can get more accurate power consumption data in deep sleep mode.

7

OK, seems you have researched it and there will be a trade-off between power consumption and the ability to respond. :grinning: