Just a couple of discoveries of the week: Backing up a system including Node-Red and the Ubuntu Segmentation Error…
I’ll try to remember to wipe this entry after the weekend (if I forget, someone remind me) – but Antonio just sent me a link to the Banggood 72 hour sale. Now as we all know, sales tend to be a bit false but If you’re interested in ESP32 – I’m pretty sure you’re not going to beat this … or for original Sonoffs this…
Enjoy. Not sure what other bargains are in there but the ESP32 – that’s the cheapest I’ve ever seen.
Does this look familiar to you? I’ve not had a chance to test one of these but I thought it worth bringing the Banana Pi Zero to your attention and can make some preliminary comments..
My “nano peripheral” started life as a simple attempt to expand the ESP8266 by making use of the IO on a really cheap Chinese board, an Arduino Nano equivalent Chinese £1.20 rip-off (After all, any Arduino is basically little more than an Atmel chip with reset and power circuitry and a “bootloader”).
UPDATE: Now working on IR – receiver already tested – see experimental version further down…
The idea was to build a dirt-cheap I2c peripheral, suitable for use with my ESP8266 code but now, with improved access to i2c on various boards such as the Orange Pi Zero (2 i2c channels), FriendlyArm NEO, M3, Raspberry Pi and others (see blog entry on i2c) it makes sense to look at this for general use – and with a widened range of capabilities.
Regular readers may recall some time ago I was buying all sorts of parts – A/D converters, port expanders etc. to help with my solar monitoring – and so some time ago I had a shot at making an I2c peripheral using an Arduino Nano…
Well, I started to make a video of this thinking it was going to be a great new uninterruptable supply. I’d listened to others, I’d read the spec (or so I thought) and this was to be the new saviour of battery supplies.
The TOMO unit comes in different sizes, I chose the 3-battery solution. I bought mine from AliExpress. It has a USB input and 2 USB outputs and can power up to 2.1 amps in TOTAL (2.1 amps out of one output OR 1 amp out of the other – must use the same chip as everyone else).
It is nice looking and comes MINUS the batteries and hence is cheap. You can use one battery or more – either way it still acts as a power supply.
So in a recent blog I’ve covered a pair of Node-Red nodes which allow GPIO access in Node-Red on a variety of boards using the underlying ONOFF library (which loads automatically when you get the nodes). And that’s all sorted now – GPIO for all – lovely. But what of the exceedingly useful I2c?
You might recall some time ago I wrote about using Python on the Orange Pi Zero etc to run the little SSD1306-based displays.
Despite that being successful I did have a nagging doubt about the LUMA library because later on – when doing some apt-get upgrades I got a segmentation error which I’d originally attributed to using a hard disk with the device. I now think it might be something to do with that library. Well, when my NEO PLUS2 arrived I thought I’d try again..
WELL!!! This version works and also works with the NanoPi AIR AND the NEO2 using the standard Ubuntu image (and has solved my problem with the hard drive on the NEO2)...
A quick note – I have made all of my sites secure (https://) and so the original OTA site for my ESP8266 ROMS (www.scargill.net) is no longer appropriate. roms.scargill.net is now the place to go (which redirects elsewhere and also has a pretty interface) – sorry for any inconvenience. The files are not seen if you visit the site, just a home page - you simply enter the name of the site followed by slash and the rom name - for example... roms.scargill.net/rom.bin
Files available are:
blank.bin and esp_init_data_default.bin are needed for utterly blank ESP12 units.
rboot.bin and rom.bin are for my new ESP8266 code (which no longer supports ESP-01)
rboot.bin and romx.bin are for my older ESP8266 code (no longer developing that version but it is fine and might run fine on an ESP-01 without OTA)
I have to say, it felt a little like Christmas today when the Correos post-lady turned up with a plastic container full of packages from China for me.
Among the many items in today’s post were the two you see above – a WEMOS board (i.e. ESP-12 + power supply) which includes an OLED display. As you’ll know I’ve recently added the SD1306 display to the commands on my ESP8266 code – looks like they’ve done the same but gone a stage further and added the actual display to the board.
(While I'm here - note the site is now https:// rather than http:// - if anyone has issues (despite refreshing the browser) - do please let me know.
The issue of running out of FLASH space on the ESP8266 is now resolved – if you are interested in how FLASH memory on the ESP8266 works - especially using the Unofficial Development Environment with the official SDK and RBOOT works – you may find this useful. I now have more FLASH than I know what to do with...
In recent previous articles I’ve been working with various displays and various processors – and one thing that comes to the fore is the importance of fonts. TTF fonts are pretty useless for small microprocessor projects as the processing overhead can be significant – and though there are many standards out there – if you want to do this all without spending money – choices are limited. In addition to that, when it comes to icons – the chances of finding a readymade font with all the stuff you need and none of the stuff you don’t need – are pretty slim.
I’ve spent WAY too many hours working on ILI9340 display updates for my ESP8266 kitchen sink C code but at least now I'm getting somewhere - that is - fast, easy serial or MQTT access to the display with multiple fonts. Note - that initial tests indicate this also applies to the ILI9341 - just over £5 from Ebay at the time of writing (Aug 2017) - https://goo.gl/DHACMw I got sick of trying to find decent fonts in bitmap mode (most of them look like something out of the 1990s) and decided the only way was to go GCLD – which is a relatively simple format with the advantage that there is a free Windows convertor/editor which takes in any old TTF font – of which there are millions – and converts them. Little did I know how many hours I'd need to put into making it work.