Inexpensive 128 x 64 OLED monochrome displays.
https://startingelectronics.org/tutorials/arduino/modules/OLED-128×64-I2C-display/
Category Archives: hardware
Rotel amp restored
Picked up a couple of dead hi-fi amps, one of them being this nice Rotel RA-820. Opened it up, gave it a clean and replaced all the electrolytics and back in business. Now sitting in the garage hi-fi cabinet for when I’m working down there.
Useful links:
- Rotel RA-820 (HiFi Engine)
- similar model (RA-820BX) useful photo reference but different values
The other amp is a Cambridge Audio A-300 (like this A-500) but it looks to be in rather a sorry state, with at least one blown output stage. Have to work out whether that one is going to be worth restoring, or may get rebuilt as a chip amp …
NodeMCU electronic switch
Here’s a really easy demonstration of how you can control outputs on the NodeMCU with a simple web interface. The NodeMCU runs as a simple web server, writing a control panel interface directly as HTML.
Hardware
The circuit is very simple, just four LEDs with resistors wired to outputs of the NodeMCU.
Here’s the wiring I used, which matches the code.
- yellow – D1 = GPIO5
- green – D2 = GPIO4
- blue – D3 = GPIO0
- red – D7 = GPIO13
In Arduino code, GPIO numbers map to Arduino digital outputs, so to turn on yellow LED use digitalWrite(5, HIGH)
Software
- Get the code example (esp8266ledControl.ino) and edit to add your wifi name and password to the code.
- Board type in Arduino IDE is ‘Node MCU 1.0 (ESP-12E Module)’
- You will need to set up your Arduino IDE to work with the NodeMCU. A good guide can be found at https://www.circuito.io/blog/nodemcu-esp8266/ (go to the last section Programming NodeMCU with Arduino IDE. Note there is a slight typo in the instructions, the board URL should end with ‘.json’ not ‘.jso’).
- Upload the code to the NodeMCU.
- When it has finished loading, quickly open the Serial Monitor, set the baud rate to 115200.
- Wait until the device joins the WiFi network, and note the IP address it obtains.
- Enter this address in a web browser, and the interface will load.
- Now you can turn on and off the various coloured LEDs by clicking on the respective buttons.
Silicon Chip module articles
A series of articles on ‘Cheap Asian’ Electronic Modules
- Low Cost Asian Electronic Modules (Oct 2016)
- Computer Interface Modules (Jan 2017)
- Measuring Temperature and Relative Humidity (Feb 2017)
- LCD Module with I2C (Mar 2017)
- Direct Digital Synthesiser (Apr 2017)
- LED Matrix Displays (Jun 2017)
- Li-Ion and LiPo Charger Modules (Aug 2017)
- Pressure/Temperature Sensors (Dec 2017)
- 2.4 GHz Wireless modules (Jan 2018)
- Sensing motion and moisture (Feb 2018)
- ESP-01 Wifi Data Transceiver (Apr 2018)
PIR sensor
Passive Infra-Red sensor detects movement.
We have vision!
I bought a Raspberry Pi camera to go with the RPi 3 for the school project. The eventual intention is to put it on our tank robot so we can see what it is seeing.
Following on from the previous tutorial IoT: Raspberry Pi Robot with Video Streamer and Pan/Tilt camera remote control over internet I installed streaming software, plugged in the camera and crossed my fingers. Loading the page showed some promise except I’d turned the lights off in the server room when I went away, so I had a square of black. Back to the server room, then back to my computer to find I was looking at the roof of the server room.
It works!
Science Talent Search – Robot Buggy
My son entered Science Talent Search with this Arduino-powered buggy. We used IR with a TV remote to issue codes for motor control and combinations of colours for the RGB LEDs.
Programming was fairly simple, but we found issues with power. It seems that motors are very noisy and when they run it can reset the Arduino. We solved this by running the motor off 4 x AA batteries, whilst the Arduino is powered by a phone battery booster. The Arduino in question is actually a Freetronics Leostick, which is a nice small board, and has a USB plug which we just plugged straight into the phone battery.
New Raspberry Pi 3 setup
This is the second Raspberry Pi I’ve bought, this one is for school projects. The really neat feature is that it has built-in WiFi.
- Download NOOBS and copy onto a MicroSD card
- Put in the MicroSD card and boot the RPi, then run the installer
- After a while, it restarts and you get the desktop. At this point it was easy just to join the home network and we’re done to this point
- At school, we set up a fixed IP address on a hidden wireless network, and used the MAC address to secure access to the network
- Proxy settings needed to be added
- Now, to run some updates. First apt-get update, then apt-upgrade
- Install vncserver so we can connect remotely using Chicken of the VNC
Now it’s time to tackle some specific jobs we need for projects.
- I used this article IoT: Raspberry Pi Robot with Video Streamer and Pan/Tilt camera remote control over internet to install lighttpd so now we have a simple web server running on the Pi . I wrote a simple page in Nano to test that it works
Raspberry Pi!
So it’s been busy, and school is just about to go back. I did find time to try out my Christmas present so I opened up the kit, plugged in the SD card and WiPi adaptor, hooked up peripherals that normally are hooked up to the Mac Mini, plugged in the power and we’re up and running. A few clicks and we’ve joined the network and posting a new item on this blog!
Arduino + shield
So this project had been sitting on my desk for ages now with the sensors and RF module spread across two breadboards with a mess of wire connecting it all up. Today I finally found some time to add the RF module to a prototyping shield. The other sensors are still on a breadboard and that’s the extra wires hanging off it, but it’s one step closer to a finished project. Some of the soldering was a bit fiddly but worked straight off.