Mimicking a Friedland Doorbell

The project goal is to ring an existing Friedland doorbell when the Ring Doorbell 4 is pressed. 

To this end I used an SDR (Software Defined Radio) USB dongle to see if it could pick up bell rings on 868 MHz. 

Looking at the back of the doorbell is has the Libra+ model number of : 48248SL and the fact it operates at 868Mz (the unlicensed instrumentation band in the UK/Ireland)

With the rtl_433 software installed on a Kali Linux desktop I got this result: 

 

Using the command:

kilnageer@mint-AMILO-Pro-Series-V8210:~$ rtl_433 -v -f 868000000 -M time

Interestingly, it sees it as a Honeywell doorbell so they must share the same RF protocol! 

So this allows me to know when someone has pressed the doorbell but can I mimic this action myself in software so that I can get the Ring doorbell to activate it? 

So to this end I bought a Honeywell ringer and a LILYGO TTGO MCU both of which have 868MHz transmitters.

The Honeywell DCP311 doorbell push button:

uses the ActivLink protocol but isn't detected by the SDR. So I've parked that approach up for now to concentrate on the TTGO MCU. Which can apparently run sniffer firmware :)

http://www.lilygo.cn/prod_view.aspx?TypeId=50060&Id=1271&FId=t3:50060:3

So my next blog post will be on this device.

 

 

ST-Link V2 Programming Unit mini STM8 STM32 Emulator Downloader M89 New Total: EUR 10.95

 Bought this on 6/2/22 for 11 euros. Hopefully it will allow me to reprogramme ST controller that Lets Talk Solar installed.

RC Boat Ready to Test at Wetlands

 I dropped the resistor down to 900R from 2K2R and the motor now comes on reliably. See YouTube video.

https://youtu.be/SGTJCwVKb_8

RC Boat for Wetlands switched to Power Transistors

Experiments with SG90 servos and board resulted in failure to drive the motors.

http://www.ee.ic.ac.uk/pcheung/teaching/DE1_EE/stores/sg90_datasheet.pdf

So rummaged around in component boxes until I found some power transistors.

The 2N3054 should do the trick:

https://octopart.com/datasheet/2n3054-comset+semiconductors-29378570

https://www.homemade-circuits.com/dc-motor-speed-controller-circuits/

I ended up with a diode across the motor with both between th NPN collector (case) and +5v from a USB power bank. Then a 2K2R resistor from base pin to micro:bit and emitter connected to GND.

Also have a red LED (longer lead to +5v) and 670R resistor across water pump motor as a visual indication.

With the NPN viewed from behind with the two pins furthest away from you the emitter is on the right (with base on the left)

Next, after testing successfully using a breadboard last night, 

I decided to commit two channels to a veroboard this morning.

Got one wired and works if signal in connected to +5v (i.e. LED and motor turn on) but not when driven by 3.5v signal from micro:bit! Strange as this worked on the breadboard last night!

After some fiddling it finally worked. So loose cable maybe? Now wiring up the second transistor.

Got second channel working (LED on when signal taken to +5v) but first channel now broken!

Fixed. Was loose solder to collector casing.

Making a radio controlled boat to take environmental readings at the Shannon Wetlands

So this is an activity which I though would inspire young people to get involved in taking and processing environment data.

It's goal is to making a boat that can carry environmental sensors to the centre of the Shannon Wetlands ponds.

My thinking being two fish tank water pumps could be the motors with their power controlled by a BBC micro:bit which could receive commands remotely from another micro:bit. The boat could be made of cardboard which is waterproofed by gaffer tape. The motor control board and code from the Kitronix Move mini robot could be re-used.

So it composes of 5 elements:

1) A waterproof hull (cardboard covered with black plastic gaffer tape)

2) A motor (two water pumps taped to the rear of the boat)

3) A receiver that controls the motors (a BBC micro:bit and motor board from a Kitronix Move)

4) A power source on the boat (a 5v USB power bank)

5) A remote control (another BBC micro:bit using tilt control for direction / speed / full stop)

The code had to provide individual power control to two submersed water pumps which provide propulsion for the boat. That is 100% power to both pumps is full steam ahead, 0% to both is full stop and 100% to left pump (starboard) and 0% to right pump (port) would turn the boat left, etc.

The MOVE mini code is a good starting point:

The Kitronix MOVE mini: https://kitronik.co.uk/products/5624-move-mini-buggy-kit-excl-microbit.html

The Servo:Lite motor board can drive up to 1A: https://resources.kitronik.co.uk/pdf/5623-servo-lite-datasheet.pdf

Library to control motor board: https://github.com/KitronikLtd/pxt-kitronik-servo-lite

Looking at their the servos what VCC, GND amd Cobtrol. And looking at the GIT library code this Control wire is drive by:

    export function forward(): void {

        pins.servoWritePin(AnalogPin.P1, 0);

        pins.servoWritePin(AnalogPin.P2, 180);

    }

    export function backward(): void {

        pins.servoWritePin(AnalogPin.P1, 180);

        pins.servoWritePin(AnalogPin.P2, 0);

    }

    export function left(): void {

        pins.servoWritePin(AnalogPin.P1, 0);

        pins.servoWritePin(AnalogPin.P2, 0);

    }

    export function right(): void {

        pins.servoWritePin(AnalogPin.P1, 180);

        pins.servoWritePin(AnalogPin.P2, 180);

    }

    export function stop(): void {

        pins.analogWritePin(AnalogPin.P1, 0);

        pins.analogWritePin(AnalogPin.P2, 0);

    }

    export function neutral(): void {

        pins.servoWritePin(AnalogPin.P1, 90);

        pins.servoWritePin(AnalogPin.P2, 90);

    }

So this the analogue voltage presented to P1 and P2 controls the servo motor.

https://www.ebay.co.uk/itm/284556271865

http://www.ee.ic.ac.uk/pcheung/teaching/DE1_EE/stores/sg90_datasheet.pdf

But for the boat I just want a voltage!

Parts list:

1) 2x DC 2.5V / 6V Small Mini Water Pump Fish Tank Fountain Aquarium Micro Submersible bought from ebay.ie for £3.50 each.

2) Re-used guts of https://kitronik.co.uk/products/5652-move-mini-mk2-buggy-kit-excl-microbit

3) Cardboard and black duck tape

4) 2x BBC micro:bit

5) 2x 5v USB power banks (from Dealz for 1.50 euro each)

Measuring Electricty Usage

The simplest way is to just read your meter and log the results. (Hopefully, eventually, the new smart meters will allow people to do that electronically!)

A less time consuming way is to install a monitor.

Though you will always need to check and apply a fudge factor to the readings from the monitor so it agrees with your true meter reading.

OK. So how do we go about all this?

Well, if you look at your electricity bills you will see your usage over the billing period (typically every one or two months).

Here's the values for a 3 bed semi in Shannon Town:

Bill	Start	Reading	Type	End	Reading	Type	Usage
15/12/20	01/11/20	92782	E	30/11/20	105	E	260.56
12/01/21	01/12/20	105	E	31/12/20	213	E	107.37
10/02/21	01/01/21	213	E	31/01/21	473	E	260.66
11/03/21	01/02/21	473	E	28/02/21	705	E	231.26
12/04/21	01/03/21	705	E	31/03/21	946	E	241.35
11/05/21	01/04/21	946	E	30/04/21	1314	E	368.30
14/06/21	01/05/21	1314	E	31/05/21	1531	E	217.04
12/07/21	01/06/21	1531	E	31/06/21	1782	E	251.03
11/08/21	01/07/21	1782	E	31/07/21	1992	E	209.20
08/09/21	01/08/21	1992	E	14/08/21	2091	E	99.09
13/09/21	15/08/21	2091	E	31/08/21	2167	E	76.72
12/10/21	01/09/21	2167	E	30/09/21	2385	E	217.20
12/11/21	01/10/21	2385	E	31/10/21	2490	E	104.98
15/12/21	01/11/21	2490	E	30/11/21	2729	E	238.94
13/01/22	01/12/21	2729	E	31/12/21	2903	E	174.78

And for a 5 bed detached single story cottage in the Mayo countryside.

Bill	Start	Reading	Type	Interim	Reading	Type	End	Reading	Type	Usage
16/12/20	16/10/20	61391	E	15/12/20	62092	A	16/12/20	62150	E	714
16/02/21	16/12/20	62105	E	20/12/20	62141	C	16/02/21	62659	E	554
16/04/21	16/02/21	62659	E				16/04/21	63139	E	480
16/06/21	16/04/21	63139	E	10/05/21	63918	C	16/06/21	64337	E	1198
16/08/21	16/06/21	64337	E	18/06/21	64456	A	12/08/21	65066	C	729
16/10/21	12/08/21	65066	C				16/10/21	65830	E	764
16/12/21	16/10/21	65830	E				13/12/21	67102	A	1272

So what next? Well what about heating oil usage?

So what does all this say? Well if you average the amount of oil (one litre of kerosene is approx. 9 units) and electricity used you find this is the average daily energy usage over the year 2021:

Shannon:

Mayo:

Now with technology all of this monitor and logging can be done automatically with a physical check every month of so to ensure its accuracy.

NodeMCU V3.4 ESP8266 ESP-12 E

Bought 10x of these on 23/1/22 for less than 70 euros but haven't done anything with them yet. They all have soldered legs for breadboard work.