Hi all!
I would like a little bit of help. I’m doing a HSC major project and would like some technical advice on something relatively simple that I can learn and complete within 5 months.
I am planning to construct a “smart bookcase” that monitors moisture levels on plants and has under-shelf LED lighting. I also want to have WiFi connectivity to connect with my mobile (using the Blynk app) and possibly Alexa.
have LED lights - for these, I would like 2 x 50cm strips (can be used in series if this is simpler) and am happy to use analogue instead of digital if easier (happy with all LEDs showing as the same colour)
WiFi enabled to connect with an app (Blynk) - if I get time, I’ll then try to connect Alexa to Blynk
Given the above, what electronics platform would best suit in terms of cost and simplicity? I have done some very, very basic Arduino things in the past but am happy to try something new. I’ve had a look and the ESP32-E platform (e.g. FireBeetle Board ESP32-E (Arduino Compatible) | DFRobot DFR0654 | Core Electronics Australia) seems interesting as it includes WiFi but I would like some more advice. I’m happy to learn as I go but don’t want to waste money by buying items that wouldn’t suit.
Welcome to the forum thanks for including a diagram of your plan.
The two soil moisture sensors you have suggested should work quite well for long term soil monitoring as they will run on 3.3V or 5V microcontrollers via the very common I2C protocol. The capacitive type sensors last a lot longer when left in damp soil.
The cheaper soil moisture sensors use two dissimilar metals and pass a small DC voltage through the probes to measure the resistance of the soil. The issue here is that two dissimilar metals in a damp environment with a DC current flow is the perfect conditions for electrolytic corrosion. The capacitive sensors get around this by not having the metals in direct contact with the damp soil.
I haven’t used Blynk myself so I’m not sure how challenging it will be to setup on a microcontroller or which hardware is going to be the best choice.
The ESP32 definitely have advantages over others by having WiFi built in but they are still targetted mostly at developers as they are a bit harder to configure and not as well documented for learners when compared with similar microcontrollers like Mico:bits, Raspberry Pi Pico, or Arduino boards.
Core posted a guide recently using the WLED smartphone app with an ESP32 board to control some LEDs, it’s not quite the same as Blynk but might be worth looking into when designing your project.
Yes this is exactly what I was thinking when I was looking at moisture sensors!
Right now, the ESP32-e is looking like the best option due to the inbuilt WiFi. I was thinking of putting a Gravity: IO Shield to make it easier to connect both soil sensors (as they both require the same I2C pins and this will create a place for both without having to tie them together).
This is the shield:
Thank you for the suggestion with the tutorial! i have had a look and it seems very interesting.
As well as this, the lights that I currently have are by Makeblock as I have used these in the past:
They are standard WS2812b LED lights so they are what I am looking to use. The only problem is that the connector will not plug into the Gravity shield or ESP32-e. Images below show the connector and the writing on the actual strip:
The distance between the middle of the 1st and 3rd holes is approximately 5mm so this would mean that between each hole is 2.5mm.
I would like to find a solution that does not require me having to cut the wires off. If there is an adapter for this connector available, I would appreciate any suggestions as it would make my life a little bit easier. Thanks!
That Gravity IO shield looks like the right tool for the job as far as connecting both sensors and the LED strip go.
This tutorial has a good visual breakdown of most of the common connector types and their pin pitches listed.
That LED strip looks a lot like JST XH but I’m not 100% sure the ‘keying’ of the connector looks right. It does have a 2.5mm pin pitch though. I’ll check one from the warehouse tomorrow. EDIT: My initial guess was wrong, it is a Molex connector with the same pin pitch but a different keying. The datasheet for the connector can be found here.
The quickest way to test your LED strip without having to match the exact connector will be to use prototyping male to female wires. They will connect to any square-pin connector like those on the IO shield.
I just had a closer look at the connector on a unit from the warehouse. I’ve updated my previous post.
You should still be able to connect with prototyping wires though so not too much has changed.
thanks for including a diagram of your plan.
