I’ve finally gotten around to making a web frontend for my Raspberry Pi & Arduino wireless sensor network. I chose Shopify’s Dashing dashboard, as its opensource and can be installed locally and not via some cloud crap. Essentially you have a HTML template into which you feed JSON data. I got a bit tied up in the JSON formatting so it took longer than it should have to get working (about 3 hours) but once I realised that most of the job placeholders were a single line of JSON, and not a whole entity, it was quite straightforward.

I’ve finished my obstacle avoiding robot project. Basically its an ATmega328p microcontroller that uses an HC-SR04 ultrasonic sensor to detect obstacles. The head moves using an SG-90 servo and a L293D dual H-bridge drives the two motors, using a library I’ve written and put on GitHub. The whole robot is powered by two 3.7v 18650 Li-Ion batteries with a DC/DC converter that drops it to 6v for the motors and a diode (and smoothing cap) to drop it further to 5v for the microcontroller and servo.

I’ve made my Pro Micro/Mini ISP breakout board and Raspberry Pi nRF24L01+ breakout board as per my previous post and decided to get on with trying out RF24Mesh. The problem there was that with the newer commits to RF24 and RF24Network, I was getting no response from the Arduino’s to the RPi. After some debugging with the author of the libraries on GitHub, we managed to find the culprit – not really the clone issue or the differing module issue, but actually a bit of an oddity in how dynamic payloads and dynamic ACKs work together.

As part of my RF24 sensor revamp, I thought I’d switch from the Jeelib low power routines to the Rocketscream library. It seems a bit unmaintained so I actually made a fork and merged in some of the PR’s which add support for the ATmega1284P and ATtiny85 and fix a few typo’s too. My fork can be found on Github. Anyway, whilst playing with my new rain sensor I thought it would be cool to save some battery power and only wake the MCU when it was raining, I didn’t need to be told it wasn’t raining every 3mins or whatever.

Next on the new sensors to play with list is a soil moisture sensor and the similar rain sensor, both use the same LM393 opamp comparator board. The pinout is: AO - A7 DO - D2 VCC - 3.3v GND - GND The digital output basically gives a 0/1 based on if the moisture/rainfall has reached a certain level (adjusted with the trimpot). My code is: const int aPin = A7; const int dPin = 2; int moisture = 0; bool isRaining = false; void setup() { Serial.