Reflow soldering with a frying pan

Here’s a quick post on how to use a frying pan to solder SMD components.

Here’s what you need:
– A populated PCB with SMD components on one side only (components on two sides does not work with this method)
– A frying pan
– A hob to heat the pan (not induction, see note below)
– A temperature sensor (like a thermocouple), this is not required, but better if you want to keep an eye on your board’s temperature.

The frying pan I used is quite cheap, I got it from Ikea for 2.50€. Any pan would do the job, just make sure the surface is flat. Also, once you used a pan to do some soldering, don’t plan on cooking with it anymore, solder paste can contain lead and other poisonous materials, so keep this one for your DIY stuff only.

Note: do NOT try this with an induction plate. I haven’t tried but the EM field used to heat the pan can be bad for your components. You need preferably a diecast iron hob, I haven’t tried with a gas hob, but I guess it could heat up faster (and would be easier to control).

Once everything is ready, just put the board in the middle of the frying pan, turn the heat to the maximum, and wait.

Keep your eyes on the board, to check when the solder paste starts to melt.

On my experiment, the fusion point occurred at 180°C, starting by the centre of the pan, and quickly moving to the edge. Once you reach that point (you can see the solder paste melting and become shiny), it’s time to remove the pan from the heat (as you don’t want to fry the components).

Leave it to cool in ambient temperature, and there you go!

Motherboard PCBs

For those of you who don’t follow me on twitter (the link is in the sidebar), here are the updates of the blog since the last post in May:

  • The Mobius Modular’s Motherboard has been reworked and produced with SeeedStudio’s PCB service (which I recommend to anyone wanting to make industrial-like prototypes in low batches, it can cost as less as 1$ the board for 10 boards, definitely something to check out). Also, it costed half the price I paid for the first version of the motherboard (though it was bigger) and I got 12 units against one, for the price of ten! And did I mention it took only half the time to manufacture it (2 weeks instead of a month).. Now I just hope the few bucks I invested in the 100% electrical testing are worth it..

  • The pictures of the Motherboard are available on Flickr.
  • I just received a package from SparkFun containing some tools to get to the hard work of assembling the SMD components on the Motherboard. I’ll write a review after a quick test to bring the (mad) DIY spirit back to the blog (have you ever tried to reflow-solder a PCB in a frying pan?)
Stay tuned for more crazy stuff :)

Mobius – Stereo Loops

In the previous message I was introducing the ability of the Mobius to use Stereo Loops. Here is the module that makes it possible. It uses two Omron relays (one for each channel), and combines both channels in one stereo Jack.
Some effects will have two mono input/output jacks, so a stereo to dual mono cable will be needed in order to use this. In the previous version of the Mobius, it needed two mono Loop modules to switch a single effect.
The Stereo Loop Module

Mobius – New module boards

Here are the pictures of the first few modules of the Mobius Modular:
Stereo IO Board + Mute function on the output:

This module is basically an IO board (Jack <-> internal connector), but with stereo capability (it is still possible to use a Mono internal cable to patch Classic Loops), and a relay to ground the output for the Mute function.
Muting the Mobius is done by pressing Bank Up and Bank Down switches simultaneously for 1 second.
Classic (Mono) Loop v4:

Mobius Modular

Some news on the Mobius project: I’ve been reviewing all my (old) files, specifications and drawings to see if there was a few things I could improve. And yes, there was one.

The Mobius was made modular. That means if you need a looper with 5 loops before the amplifier and 3 in the FX loop, you can have that, as well as one with all 8 loops in a single chain. This allows the Mobius to adapt to the guitarist/bassist’s set. But we can push the idea further.
A few remarks I have been given were that it was not possible to switch stereo effects without using two mono loops, and that there was no possibility to have parallel loops. This is now over! By introducing Stereo Send/Return modules, we can now switch stereo effects with only one module.
This is one example of what the modularity gives. More modules = more combinations, more possibilities.
Here is what I’ve been thinking about so far:
  • Stereo Loop board (Stereo Send/Return)
  • IO board with Mute relay
  • IO board with Mixer (to blend parallel loops on the output)
  • Split board (also called Y module, select an output or an input)
  • Dedicated Amp channel selector (to replace the amp’s footswitch).

MIDI Library – Callbacks

I published the release 3.1 of the Arduino MIDI Library, that adds the callback feature.

This allows you to handle input messages more easily and more efficiently. Instead of checking which message was read, connect a function to a type that will be called back (hence the name) when a message of this type is received. The data is passed in the function’s parameters so you no longer need to call MIDI.getType, MIDI.getData1 etc..
Also, version 3.1 corrects a few bugs on Thru, Running Status and the interleaving of RealTime messages. If you had troubles with your MIDI-equipped sound card, give a try to this update, the trouble might be caused by Active Sensing messages messing around with other types.

Native MIDI USB Controllers with Arduino

I was recently contacted by Paul from the Teensy project to port the Arduino MIDI Library to his board, to be able to send and receive MIDI messages over the USB port and make it so that the board would be recognised as a MIDI controller in any DAW (or software handling MIDI).

More recently, I also noticed that the Arduino Uno has a dedicated USB chip (no longer the good old FT232RL) that can be programmed to act as any USB device (eg: MIDI).
These boards usually have a serial port in addition to the USB communications, which allows to kludge MIDI plugs and to get the perfect MIDI controller, just by adding sensors and programming the behaviour.
This is the development line for the next release of the library, to be able to simply create MIDI controllers with just one board, one USB connection, and that’s all.