Posts with «general» label

Spoooky CircuitPython Circuits!

After using Python for a decade, I’ve decided to finally get better at it. I think diving into CircuitPython will be a nice scaled-down universe to learn to write concise “Pythonic” code. For hardware I’m using Adafruit’s new QT Py board and CircuitPython’s new ESP32-S2 support. And for a theme this month I want to [...]
Todbot 09 Oct 19:28
arduino  general  hardware-hacking  

Prevent annoying Mac ._ files on CIRCUITPY

Example: Unzip & Download files to CIRCUITPY The entire process in a single session, using a neopixel example: Background On the Mac, the OS stores a bunch of different meta information about files inside those files. These are called “Extended Attributes” or “xattrs”. If you copy a file on a Mac to a thumbdrive or [...]
Todbot 04 Oct 06:48
general  

Touring Machine First PCBs!

Last week I submitted PCBs to be fabbed and got them back this week. They look pretty good! I’ve not soldered anything down yet but the footprints are all good except for the rotary encoder mounting holes. The Eagle part I used has them at 2.05mm but they need to be 2.4mm. I need to [...]
Todbot 18 Sep 19:57
general  

The Start of the Touring Machine Eurorack module

The original goal of my month-long Deep Fried Neurons project was “30 sounds, one per day”, an exploration into making sounds with Eurorack gear that doesn’t use sequencers or keyboards. While I only create 15 sounds so far (I’ll still do all 30 I think), I’ve been increasingly using some home-built modules like my TrinketTrigger [...]
Todbot 28 Aug 18:40
general  music  

30 sounds, one per day

I’ve decided to do “30 sounds, one per day”.  I’m a bit behind, but here’s a Youtube playlist of what I have so far and the corresponding Bandcamp album. These are to be sounds. Not tracks, not songs. Just interesting sonic experiments. I want to make sounds I’ve never heard before, or sounds I’ve always wanted [...]
Todbot 07 Aug 20:09
general  music  

Fixing my Macbook Pro after it was “repaired” by Rossmann Repair Group

The short of it: I do not recommend Rossmann Repair Group for Mac repairs. In my case they showed repeated lack of care and little attention to detail, sending me back a computer that while it technically worked, was unusable. The problems I had with their laptop repair: Wrong logic board installed (2.5 GHz vs [...]
Todbot 20 Jun 08:39
general  

Review of some electronics kits for kids

Continuing on the topic of "Introduction to Practical Electronics" course, today we are going to look at some of the electronics (soldering) kits available and suitable for the purpose.

What makes a good beginner electronics kit?
  • easy through-hole soldering
  • includes a variety of components
  • reasonably priced (this is relative; what may be expensive for me may be cheap for you)
  • standalone and all-inclusive: does not require extra parts/components/modules sourced from third parties and does not require loading software;
  • interesting (as opposed to boring) functionality: flashes LEDs, displays something on a screen, makes some sounds etc.
  • relative simplicity of the circuit, so it can be easy to understand and debug if necessary
  • aesthetics of the board (shape, colour, component placement etc.)
  • preferably open source
  • powered by low voltage (battery, USB, power adapter)
  • digital electronics rather than analog (easier to debug, if necessary)
  • practical utility: use it for a utilitarian purpose rather than forget about it once built
  • expandability: can be either integrated as part of a bigger project, or its capabilities and functionality can be extended by adding modules or parts
  • provides extra learning (besides soldering) by displaying information: wave forms, frequencies, binary/hex number representation, musical notes, proverbs etc.
  • satisfaction guaranteed once assembled and working  :)
Here is a list, in no particular order, of beginner kits I found to match some of the above criteria.

1. Elenco AM Radio kit


2. Chinese Radio kits: A, B



3. 6-digit LED Clock kit


4. 4-digit LED Alarm Clock kit


5. 4-digit LED Talking Clock kit



6. Elenco two-tone European Siren kit


7. Retro Classic Game (Tetris, Snake etc.) kit


8. 3D Christmas Tree Flashing LEDs kit


9. Electronic Piano kit


10. Electronic 16 Sound Music Box kit


11. Astable Multi-vibrator Circuit Learn kit


12. Mini Speaker Box Amplifier kit


13. Aviation Band Radio Receiver kit


14. Calculator and Counter with LCD and Keyboard kit


15. "Three Fives" Discreet 555 Timer kit


16. TV-B-Gone kit


17. MintyBoost kit


18. MintySynth kit (now discontinued)


19. Drawdio kit


20. Electronic Hourglass LED kit


21. Round LED Clock kit


22. Signal Generator with XR2206 Adjustable Frequency kit


23. Solder:Time Desk Clock kit


24. Geiger Counter kit(s)


25. Wristwatch LED kit


26. Burglar Electronic Alarm kit


27. Conway's Game of Life kit


28. Music Synthesizer kit


29. Line Following Robot kit


30. Jameco Atari Punk Console kit


31. 555 Forrest Mims Project kit(s)



32. Tesla Coil kit


33. Velleman voice changer kit



34. Various badges (Maker, Day of Geek, Unicorn, and many many others)


Wise time with Arduino 14 Apr 23:36
general  review  

JAMuary 2020: Modular synths & Deluge

I’ve been getting back into music lately, thanks to the wonderful Synthstrom Deluge. And thanks to John Park, I’ve been getting into Eurorack modular synthesizers. It’s really fun, but can get pricey fast. I would recommend everyone download the free VCV Rack so you too can patch together sound modules like audio Lego and make [...]
Todbot 04 Apr 23:10
general  

Teaching Electronics to Kids

My "Introduction to Practical Electronics for Children" course concluded successfully a few weeks back, before March break. Now, with schools closed for covid19, it would be a good time for the kids to practice soldering and learn by doing. At this stage, I think it is easy to expand their knowledge and skills in the field of electronics just by assembling kits.

Here are a few notes and observations from my teaching.
  • Each class had 6 groups of 3 students sharing a soldering station. This (not my decision) was probably based of space constraints (6 desks in a normal-sized classroom) and safety/supervision considerations. It worked pretty well: the 2 students (in each group) not soldering had time to observe, analyze, think and to ask lots of questions. Two professional teachers assisted, with supervision, helping the students and keeping discipline.
  • Each student had their own "HDSP clock" kit to assemble. It took 6 one-hour sessions to complete, with a success rate of about 95% (2 failures out of 38 assembled, because of solder bridges).
  • The intended "50% theory and 50% practice" ratio had quickly become 10/90. Still managed to introduce components (resistor, capacitor, crystal), electrical concepts (AC vs DC, voltage, resistance, current, frequency) and units of measures (Volts, Farads, Ohms, Hertz). We even talked about Tesla batteries :)
  • Some parts were lost (e.g. crystal) or damaged (dropped, then stepped on by accident) between or during the classes. The lesson learned is to have extras available.
  • Each student received individual instructions, guidance, assistance and supervision on soldering. We came up with the "3-second rule" to make a good soldering joint: hold the tip of the soldering iron in contact with the pad and the terminal for 3 seconds while touching and melting the solder wire on the tip.
  • Having students pay attention to the instructions was very important. It saves energy to talk once to the whole class, rather than answering the same question to each individual. (I also learned from professional teachers  the "1-2-3 eyes on me" attention-getter.)
  • Sockets for integrated circuits are a must in a beginner kit. Imagine fixing an IC soldered in the wrong orientation! (The "worst" that happened was that all 3 ICs in the kit were soldered directly onto the board, luckily in the correct orientation.) Also, silkscreen should be as detailed as possible, indicating the component's place. In case of the "HDSP clock" kit, the students were able to easily identify the placeholders for each component, just by using logic (except for the resistors; they learned quickly to bend the resistors' terminals).
  • Some of the most frequent mistakes were soldering bridges and filling empty holes with solder. Bridges were easily fixed (initially by me, then the students learned to do it themselves) using the copper wick/braid, and flux. To fix the solder-filled holes, I had to use a tailor pin (part of my EDC Swiss card).
  • Surprisingly, every student showed interest in working on, and completing, the kit. I think it was a successful experiment even for the school, in making "practical electronics" as part of their curriculum. Like in the old days of practical skills teaching (wood working for boys, sewing or cooking for girls), this course demonstrated that Grade 6 students are very capable and eager to acquire skills that may stay with them for life.

Wise time with Arduino 21 Mar 16:42
general  review  

Teardown of an Old Dimmer Switch

The 40+ year-old dimmer (made by Nortron Industries Limited in Milton, Ontario) in my attic broke down. Electronically, the dimming circuit still worked, but mechanically, the push button got stuck.
This is what's inside, for the curious.



The active component in the circuit is Q2006LT, a "quadrac" which, according to the datasheet, "is an internally triggered Triac designed for AC switching and phase control applications. It is a Triac and DIAC in a single package, which saves user expense by eliminating the need for separate Triac and DIAC components".

The "reversed-engineered" schematic looks like this:


For those who want to understand more on how the triac-controlled dimmer works, this article provides an in-depth explanation.

The 250V capacitors may be reused in a Nixie high-voltage (~170V) power source. For a hoarder, both the choke and the potentiometer (push button removed) look good.

I will report back on the internals of the replacement switch in 40 years or so, when it breaks down. I hope I/it last(s) that long.

Wise time with Arduino 15 Mar 22:29
general  hacking  review