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Wemos D1 Mini random PCB thickness

If you order a “Wemos D1 Mini” you’d expect to get the same thing every time, right?

Wrong!

The Wemos brand has become a victim of counterfeiters, who make a near-exact copy of the board and then produce it as cheaply as they can. These two D1 Minis look superficially similar, and if they were lying on the bench you would probably have trouble telling them apart:

But look closer. The shape of the PCB is slightly different around the top edges, and the silkscreen is slightly different. It’s most obvious around the “5V” label near the bottom left. There’s also slightly different soldermask pullback around the pads. The board on the left has several parts out of alignment, although electrically they’re still connected and the board works fine.

Part of reducing the cost is to use whatever is the cheapest PCB substrate they can get their hands on at the time. These D1 Minis were made using totally different PCB material:

One PCB is 1mm thick, and the other is 1.6mm.

I’ve seen D1 Minis with 0.8mm, 1.0mm, 1.2mm, 1.4mm, and 1.6mm PCBs! You really can’t predict what you’re going to get.

Why does this matter?

Most of the time, it doesn’t. But recently I heard from someone trying to build my Air Quality Sensor project that their D1 Mini wouldn’t fit in the 3D printed case, because the case only allows PCBs up to 1.2mm thick! Oops.

So I’ve now generated STLs for both 1.2mm and 1.6mm slots, for both the “Basic” and “Display” versions of the case. You can grab the latest STLs from the product pages, linked from the respective episodes:

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ESP32 pin allocation spreadsheet

The ESP32 is a fantastic MCU, but when you are designing a project with it you need to choose the I/O pins very carefully.

Many of the I/O pins have special purposes, such as being bootstrapping pins that change the way the ESP32 boots up. Some have limitations, such as being OK to use as inputs but they don’t have pullup or pulldown resistors, so you have to bias them externally.

And some of the strange behaviour is really obscure: for example, you can’t use analog input on any pin associated with ADC2 while WiFi is in use!

To help me navigate these limitations I created a spreadsheet that lists the pins and their strange behaviour:

When I start a new project, I use this spreadsheet as a template and make a duplicate just for the project. Then I add notes to the “Purpose” column to say what I’m going to use each pin for.

I’ve made the template public, so you can make copies of it yourself for your projects. Click the preview above to open it in Google Sheets.

Many of the cells have notes attached to them, explaining specific limitations.

Because I mostly use Wroom32 modules, the spreadsheet has a column for Wroom32 pin numbers. You can change this to suit whatever module you use in your project, or ignore it and work from the direct ESP32 pin numbers which are also listed.

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International shipping suspended

Because of the decrease in international travel over the last couple of months, the postal service doesn’t have enough flights available to carry international letters and parcels.

As of this week, Australia Post can’t process “Economy” class international packages at all. Some premium classes of package, such as trackable services and International Express, are still being accepted at post offices. However, even these more expensive shipping options are experiencing weeks of delays.

Sadly, this means that I simply can’t ship international packages at the moment. I can still ship orders to Australian customers without any problems: domestic packages are being processed and transported as normal. It’s the lack of international flights that is the big problem.

I’ve now turned off all shipping methods for international customers.

The moment that the postal service has resumed international service, I’ll turn international shipping back on. Until then, I can only process orders for Australian customers.

I’m really sorry about that 🙁

In the meantime, please join the SuperHouse Discord chat server and the SuperHouse forum, and join me every Sunday at 10am Melbourne time for a livestream to chat about whatever fun projects we’re working on during the lockdown! This period of isolation can be hard, but we can also use it as an opportunity to connect more online and learn from each other.

Jon

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Coronavirus and electronics production

I’m sure you’ve heard of the crazy coronavirus epidemic that’s rapidly spreading around the world, and has now been declared a global health emergency by the World Health Organization.

One of the areas that has been hardest hit by the virus is the city of Wuhan, on the Yangtze River in east-central China. Wuhan went into a state of lockdown on January 23rd, with businesses closed and everyone told to stay home and avoid contact with other people.

China is taking this threat extremely seriously, responding on a scale that I don’t think would be possible in any other country. I don’t know of anywhere else in the world that could build entire 1000-bed hospitals from the ground up in 6 days, just to respond to a sudden medical need. If anyone can face a challenge like this, it’s the Chinese.

The primary focus has to be on the health of those in the affected areas, of course. So far I haven’t heard of any of my Chinese colleagues being infected, and I hope it stays that way.

Bare PCBs for both Freetronics and SuperHouse products are mostly produced by Gold Phoenix, which is located in Wuhan, right in the bullseye of the epidemic. Like almost all businesses in Wuhan, Gold Phoenix has told workers to stay home and stay safe.

Some of our prototype PCBs are produced in factories around the city of Shenzhen, in southern China just over the border from Hong Kong. Those factories are currently closed too.

Our PCBA (PCB Assembly, which includes pick-and-place installation of parts on the boards) and final testing and packaging is done in Beijing, which has now also gone into lockdown. Not only are factories closed, but roads out of the cities have been closed to prevent the spread of infection so any boards that have aleady been produced are stuck in warehouses.

There are currently batches of EtherMega and EtherTen boards that were scheduled to ship a few days ago, but they are now caught up in the lockdown and can’t leave Beijing.

So over the next little while there will probably be stock problems for both Freetronics and SuperHouse. Please be patient while I do my best to assemble what I can using local stock of bare PCBs and parts, and keep in mind the millions of people who are now stuck at home with dwindling food supplies. It may be frustrating that products are out of stock, but that’s really not important when the health of so many people is at stake.

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Open Source wheelchair controller first full test

Still plenty of work to do, and the controls are too twitchy, but it works!

This is a combination of the Chair Breakout Mini (to read the joystick position and transmitting it on CAN bus) and the Wheelchair Motor Controller, which receives the messages and drives the motors and brakes.

We’re making rapid progress on a number of Assistive Technology projects, so if you want to join in the discussion please join the SuperHouse Discord server and use the #assistive-tech channel.

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iLife Robot Hoover Automation in Home Assistant with Wemos & IR Shield

Colin Hickey has an interesting YouTube channel that features some of his cool home automation projects. What I like about his videos is that he doesn’t just show the end result: he goes through his setup step by step so that you can do the same thing yourself.

If you go back through his videos you’ll find plenty of fascinating information about his home-made PowerWall and battery management system.

His latest video should be interesting to anyone who has an iLife robot vacuum cleaner, so check it out and make sure you subscribe to his channel:

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High security package vault

Defeat package thieves with a combination of technology and steel!

Having packages stolen from your doorstep can be a big problem in a normal suburban neighbourhood, but when your front gate is at the end of a very long driveway in a remote area it’s even worse. Your packages could sit exposed by the side of the road for hours when you don’t even know they’ve been delivered.

SuperHouse forum member Guru_Of_Nothing was sick of package thieves taking his deliveries, so he’s started building a super-strong, high tech package vault:

The design is very clever because it covers various contingencies, including being able to open the box mechanically if there is a power failure, and handling multiple deliveries in a single day.

This is just the start of the project, so follow Guru’s progress on the forum at https://discourse.superhouse.tv/t/a-new-item-to-automate-the-mailbox/245/9

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Video of my conference talk “Open Source Superhumans”

I spent last week in Christchurch, New Zealand, for the always amazing linux.conf.au conference. It’s my annual pilgrimage: I’ve attended every single LCA since 2002, and this year I presented a talk about my work using DIY home automation projects to help a couple of old friends who have Duchenne Muscular Dystrophy and rely on electric wheelchairs for mobility.

This was a very difficult talk to give because it tells a story that is both tragic and uplifting. The projects I’ve worked on with Nick and Chris Fryer have been some of the most rewarding things I’ve ever done, but along with that came the terrible grief of Nick’s death last year.

Many people have the preconception that home automation is “expensive toys for rich lazy people”, but this talk shows that it’s far more than that.

If you personally benefit from the use of home automation, or have friends or family members who do, I’d love to hear about it. Please comment here or post in the forum, but of course please be respectful of privacy and don’t reveal personal information about anyone else unless they are OK with it.

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Shipping closed during December 2018

During December I’ll be taking a break from shipping orders from the SuperHouse and Freetronics online stores.

Any orders placed after December 4th, 2018 will be shipped right after Christmas, hopefully around December 28th and 29th. If you want to get something in time for Christmas, make sure you place your order now!

I’ll be back with more videos and a bunch of new products after Christmas.

See you then!

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Join me for another livestream tour through more Eagle projects

Join me for a SuperHouse livestream tomorrow morning at 9am Sunday Melbourne time (GMT+1000)

This will be part 2 of my tour through my Eagle projects, going through them alphabetically and showing how they work.

Last time it took me 2.5 hours and I didn’t even get through the projects starting with “A”, so there’s a long way to go!

Picking some representative locations that time works out to be:

  • Melbourne: 9am Sunday
  • London: 12am Sunday (midnight)
  • Los Angeles: 4pm Saturday
  • New York: 7pm Saturday

If you don’t want to miss out, make sure you’re subscribed to my YouTube channel and click the little “bell” icon so you get a notification when the live stream starts:

www.youtube.com/user/superhousetv