Gecho v2 production update - June

Because you asked for Lime Green

We added a new colour to silicone buttons selection. Hope you like it! :)

Manufacturing of the hardware

The final designs, including gerbers (PCB board layout), assembly blueprints, stencil design (for putting soldering paste on board panels) and pick & place data (the code for machines that will put components on boards) were sent to our trusted partner's assembly house in Poland in 2nd week of June, and everything was paid for as well. This represents about a week of delay against original plan, as I wanted to have this sorted in very beginning of June. White LEDs that we had picked went out of stock in all major suppliers, so a new type had to be chosen and tested. Thankfully there was no shortage on other components. The memory chip was upgraded from 8MB to 16MB, not only to give more room for code and factory-programmed samples, but to make it a bit faster.

There were some improvements done last minute, such as SD card slot was replaced with better one that has a counter-spring locking mechanism, so it is a lot easier to remove card from it. Also the powering circuit was redesigned, so it now runs smoothly from nearly 2.9V - previously, as the battery voltage decreased below 3.5V (every AA cell discharged to <1.2V from it's normal 1.5V level), interference started to become audible in the sound. It would not be much of a problem with normal AA batteries, but would cause shorter lifespan or rechargeables (Ni-Cd, Ni-MH) as they operate at lower voltage. This problem was inherent from the version 1, because of how much current the IR sensors draw - although the light they emit is invisible, they take more than any other LED (you can see how bright they are when looking at them through the smartphone camera) and this inevitably creates ripples in stabilized voltage.

The problem was significantly mitigated by using 3.0V regulator instead of 3.3V, adding a better filtering between analog and digital voltages and grounds, and a MOSFET transistor as a barrier for current backflow into the batteries, when powered from USB (as opposed to Schottky diodes used in previous designs). This modification increases the performance with nearly depleted batteries, but also means a trade-off with CV/Gate/Sync-out voltages range. However, it turns out in the real world the 0.3V decrease does not mean any significant loss of compatibility - the devices that will not work, would not work with 3.3V either - they would require 4V+ voltages anyway. For example, the RaKits Drum Synth reacts to Gecho's voltages very well (both TRIG and PITCH CV inputs).

As for input ranges, the safe voltage for CV/Trigger/Gate is 10V+ and as the ADC have programmable attenuation, the software can select between ranges of 3V, 4.1V, 5.8V or 9V - all translating to 12-bit values (0-4095).

The "Complete Unit" enclosure

The complete unit with or without the wooden box (including DIY version) uses the same material as PCB boards - black matte 1.6mm FR-4 fiberglass composite with lead-free tin finish that gives it the silver look (as opposed to the front panel, which is gold plated). The first version is almost perfect but there are still a few places where panels are hard to put together, mainly because of how routing of the slots and outlines works - it is never precisely sharp edged, and that's not easy to predict (I haven't ordered such panels from this factory before so was not sure what diameter of CNC drill are they going to use). Small modifications were required; also the edges were shaved by 0.5mm, to leave more space for cables / connectors. The look and feel stays unaffected. Updated panels are on the way, after they are here (supposedly next week), we can confirm final dimensions and the manufacturing of wooden boxes will go ahead.

Acrylic sandwich

The samples for all panels arrived last week and they fit the prototype board precisely. Some of you had questions about exact dimensions, please see everything explained on the following picture:

Narrowing down your order details

You will get a chance to select colour of silicone buttons for every unit you've ordered, and if you changed your mind in the light of new information, to update your powering scheme as well. Also there will be an option to confirm or update shipping address, and if required, add a separate billing address. You will receive a link to amend / finalize your order shortly before shipping (please check in spam from time to time as emails containing links often end up there).

More photos

A few photos were added to preorder page (the gallery is at the end and unfolds as you scroll down), also we are posting fresh info about what has arrived, was assembled, tested and demoed, to Instagram - @gechologic / @phonicbloom.