Entries tagged esp8266

Related tags: 3d-printing, 3dhubs, arduino, automation, radio, youtube.

A busy week or two

Thursday, 12 October 2017

It feels like the past week or two has been very busy, and so I'm looking forward to my "holiday" next month.

I'm not really having a holiday of course, my wife is slowly returning to work, so I'll be taking a month of paternity leave, taking sole care of Oiva for the month of November. He's still a little angel, and now that he's reached 10 months old he's starting to get much more mobile - he's on the verge of walking, but not quite there yet. Mostly that means he wants you to hold his hands so that he can stand up, swaying back and forth before the inevitable collapse.

Beyond spending most of my evenings taking care of him, from the moment I return from work to his bedtime (around 7:30PM), I've made the Debian Administration website both read-only and much simpler. In the past that site was powered by a lot of servers, I think around 11. Now it has only a small number of machines, which should slowly decrease.

I've ripped out the database host, the redis host, the events-server, the planet-machine, the email-box, etc. Now we have a much simpler setup:

  • Front-end machine
    • Directly serves the code site
    • Directly serves the SSL site which exists solely for Let's Encrypt
    • Runs HAProxy to route the rest of the requests to the cluster.
  • 4 x Apache servers
    • Each one has a (read-only) MySQL database on it for the content.
      • In case of future-compromise I removed all user passwords, and scrambled the email-addresses.
      • I don't think there's a huge risk, but better safe than sorry.
    • Each one runs the web-application.
      • Which now caches each generated page to /tmp/x/x/x/x/$hash if it doesn't exist.
      • If the request is cached it is served from that cache rather than dynamically.

Finally although I'm slowly making progress with "radio stuff" I've knocked up a simple hack which uses an ultrasonic sensor to determine whether I'm sat in front of my (home) PC. If I am everything is good. If I'm absent the music is stopped and the screen locked. Kinda neat.

(Simple ESP8266 device wired to the sensor. When the state changes a message is posted to Mosquitto, where a listener reacts to the change(s).)

Oh, not final. I've also transfered my mobile phone from DNA.fi to MoiMobile. Which should complete soon, right now my phone is in limbo, active on niether service. Oops.

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Started work on an internet-of-things Radio

Tuesday, 26 September 2017

So recently I was in York at the Bytemark office, and I read a piece about building a radio in a Raspberry Pi magazine. It got me curious, so when I got home to sunny Helsinki I figured I'd have a stab at it.

I don't have fixed goal in mind, but what I do have is:

  • A WeMos Mini D1
    • Cost €3.00
    • ESP8266-powered board, which can be programmed easily in C++ and contains on-board WiFi as well as a bunch of I/O pins.
  • A RDA5807M FM Radio chip.
    • Cost 37 cents.
    • With a crystal for support.

The initial goal is simple wire the receiver/decoder to the board, and listen to the radio.

After that there are obvious extenstions, such as adding an LCD display to show the frequency (What's the frequency Kenneth), and later to show the station details, via RDS.

Finally I could add some buttons/switches/tweaks for selecting next/previous stations, and adjusting the volume. Initially that'll be handled by pointing a browser at the IP-address of the device.

The first attempt at using the RDA5807M chip was a failure, as the thing was too damn small and non-standardly sized. Adding header-pins to the chips was almost impossible, and when I did get them soldered on the thing just gave me static-hisses.

However I later read the details of the chip more carefully and realized that it isn't powerfull enough to drive (even) headphones. It requires an amp of some kind. With that extra knowledge I was able to send the output to the powered-speakers I have sat beside my PC.

My code is basic, it sets up the FM-receiver/decoder, and scans the spectrum. When it finds a station it outputs the name over the serial console, via RDS, and then just plays it.

I've got an PAM8403-based amplifier board on-order, when that arrives I'll get back to the project, and hookup WiFi and a simple web-page to store stations, tuning, etc.

My "token goal" at the moment is a radio that switches on at 7AM and switches off at 8AM. In addition to that it'll serve a web-page allowing interactive control, regardless of any buttons that are wired in.

I also have another project in the wings. I've ordered a software-defined radio (USB-toy) which I'm planning to use to plot aircraft in real-time, as they arrive/depart/fly over Helsinki. No doubt I'll write that up too.

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Security is hard ..

Tuesday, 30 May 2017

3D-Printing

I continued to be impressed with local vendors, found on 3dhubs. I've had several more things printed out, including an "internet button", and some card-holders for Settlers of Catan.

The most recent print I had made was a collection of display cases, for holding an OLED display, as well as an ESP8266 device.

Unfortunately at the same time as I was falling in love with the service I discovered a glaring XSS attack against the site itself.

Anybody who viewed my profile page could have arbitrary javascript executed, which in some cases would actually disclose their private details - such as:

  • Their forename & surname.
  • Their email-address.
  • Their telephone number.
  • Their GeoIP details.

Discovering this took minutes, writing it up took an hour, and a month later it is still unfixed.

I've deleted my account.

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3d-Printing is cool

Thursday, 20 April 2017

I've heard about 3d-printing a lot in the past, although the hype seems to have mostly died down. My view has always been "That seems cool", coupled with "Everybody says making the models is very hard", and "the process itself is fiddly & time-consuming".

I've been sporadically working on a project for a few months now which displays tram-departure times, this is part of my drive to "hardware" things with Arduino/ESP8266 devices . Most visitors to our flat have commented on it, at least once, and over time it has become gradually more and more user-friendly. Initially it was just a toy-project for myself, so everything was hard-coded in the source but over time that changed - which I mentioned here, (specifically the Access-point setup):

  • When it boots up, unconfigured, it starts as an access-point.
    • So you can connect and configure the WiFi network it should join.
  • Once it's up and running you can point a web-browser at it.
    • This lets you toggle the backlight, change the timezone, and the tram-stop.
    • These values are persisted to flash so reboots will remember everything.

I've now wired up an input-button to the device too, experimenting with the different ways that a single button can carry out multiple actions:

  • Press & release - toggle the backlight.
  • Press & release twice - a double-click if you like - show a message.
  • Press, hold for 1 second, then release - re-sync the date/time & tram-data.

Anyway the software is neat, and I can't think of anything obvious to change. So lets move onto the real topic of this post: 3D Printing.

I randomly remembered that I'd heard about an online site holding 3D-models, and on a whim I searched for "4x20 LCD". That lead me to this design, which is exactly what I was looking for. Just like open-source software we're now living in a world where you can get open-source hardware! How cool is that?

I had to trust the dimensions of the model, and obviously I was going to mount my new button into the box, rather than the knob shown. But having a model was great. I could download it, for free, and I could view it online at viewstl.com.

But with a model obtained the next step was getting it printed. I found a bunch of commercial companies, here in Europe, who would print a model, and ship it to me, but when I uploaded the model they priced it at €90+. Too much. I'd almost lost interest when I stumbled across a site which provides a gateway into a series of individual/companies who will print things for you, on-demand: 3dhubs.

Once again I uploaded my model, and this time I was able to select a guy in the same city as me. He printed my model for 1/3-1/4 of the price of the companies I'd found, and sent me fun pictures of the object while it was in the process of being printed.

To recap I started like this:

hardware-button

Then I boxed it in cardboard which looked better than nothing, but still not terribly great:

hardware-boxed

Now I've found an online case-design for free, got it printed cheaply by a volunteer (feels like the wrong word, after-all I did pay him), and I have something which look significantly more professional:

hardware-3d-printed

Inside it looks as neat as you would expect:

case internals

Of course the case still cost 5 times as much as the actual hardware involved (button: €0.05, processor-board €2.00 and LCD I2C display €3.00). But I've gone from being somebody who had zero experience with hardware-based projects 4 months ago, to somebody who has built a project which is functional and "pretty".

The internet really is a glorious thing. Using it for learning, and coding is good, using it for building actual physical parts too? That's something I never could have predicted a few years ago and I can see myself doing it more in the future.

Sure the case is a little rough around the edges, but I suspect it is now only a matter of time until I learn how to design my own models. An obvious extension is to add a status-LED above the switch, for example. How hard can it be to add a new hole to a model? (Hell I could just drill it!)

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I've built a product, not a project

Thursday, 2 February 2017

The past few days I've been doing more arduino-work. In between dying of sleep-exhaustion.

One thing that always annoyed me was that I had to hard-code my WiFi credentials in my projects, with code like this:

//
// Connect to the SCOTLAND network
//
WiFi.mode(WIFI_STA);
WiFi.hostname("tram-clock");
WiFi.begin("SCOTLAND", "highlander1");

//
// Attempt to connect - TODO: Timeout on failure
//
while (WiFi.status() != WL_CONNECTED)
    delay(500);

//
// Now we're connected show the local IP address.
//
lcd.print("WiFi connected  ");
lcd.print(WiFi.localIP());

Whilst looking at another project I found a great solution though. There is a library called WiFiManager which behaves perfectly:

  • If you've stored connection details it will connect to the local WiFI network using those, automatically.
  • If you've not saved previous connection details it will instead configure the device to work as an Access Point
    • You can then connect to that access point and see a list of local WiFi networks.
    • Choose the appropriate one from the list, enter your password, and these details are saved for the future.
    • The device will then reset, join the network via your saved choices and acquire an IP via DHCP as you'd expect.

The code for this is beautifully simple:

//
// Connect to WiFI with saved credentials, if any.
//
// Otherwise work as an access-point, named TRAM-TIMES, and
// let the user fill out their details.
//
WiFiManager wifiManager;
wifiManager.autoConnect("TRAM-TIMES");

This means my current project, which continues to revolve around tram-times, is so very much more user-friendly. It is a product you could package and take to a friends house, not a project you have to recompile to tweak.

For that reason, user-niceness, I reworked the on-board HTTP status-page to use bootstrap, be themed, and look nicer. Other than being housed in a horrid case the project actually looks like a product. Not one I'd buy, but neither one I'm ashamed of sharing.

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So I've been playing with hardware

Saturday, 28 January 2017

At the end of December I decided I was going to do hardware "things", and so far that has worked out pretty well.

One of the reasons I decided to play with Arduinos is that I assumed I could avoid all forms of soldering. I've done soldering often enough to know I can manage it, but not quite often enough that I feel comfortable doing so.

Unfortunately soldering has become a part of my life once again, as too many of the things I've been playing with have required pins soldering to them before I can connect them.

Soldering aside I've been having fun, and I have deployed several "real" projects in and around my flat. Perhaps the most interesting project shows the arrival time of the next tram to arrive at the end of my street:

That's simple, reliable, and useful. I have another project which needs to be documented which combineds a WeMos D1 and a vibration sensor - no sniggers - to generate an alert when the washing machine is done. Having a newborn baby around the place means that we have a lot of laundry to manage, and we keep forgetting that we've turned the washing machine on. Oops.

Anyway. Hardware. More fun than I expected. I've even started ordering more components for bigger projects.

I'll continue to document the various projects online, mostly to make sure I remember the basics:

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