Jan 13, 2016 07:00PM: Electronics Wednesday

Space opening
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event created by: Alex Satrapa

It’s the beginning of a new year! What projects will you be working on, what do you need help with, or what do you want to show off? Come on down and let us know!

Open for 180.0 minutes, closing at Jan 13, 2016 10:00PM

Please check the MHV Calendar for the latest information about events.

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I will attend.

I’m planning to bring some ESP8266 toys such as the WS2801 RGB-Leds that now work really nicely.

If anybody is interested to hear about what’s happening in Europe in IoT then happy to give an update.

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So not today (Jan 6)?

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Sorry for the very late reply, not tonight.

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I got my rgb-led for the ESP8266 working.

Actually, I’m trying to do an Ignition Coil Driver. The RGB LEDs were handy to help with the debugging of the basic program.

This test got a bit confused, because I decided to plug the ignition-coil driver setup to see if it would fire the fuel injectors. It did. I will hook up the Spark+Coil and try again later.

esp8266-driving-fuel-injector.png800×517 605 KB

Flashing RGB LED for Ignition Coil Driver Video

coilOut = 3
dwellTime = 4

gpio.mode(coilOut,gpio.OUTPUT)

function coilOff()
    gpio.write(coilOut,gpio.LOW)  
    ws2812.writergb(3, string.char(0,0,102))
end

function coilOn()
    gpio.write(coilOut,gpio.HIGH)
    ws2812.writergb(3, string.char(255,204,204))
end
    
tmr.alarm(0,1000,1,function()
    coilOn()
    tmr.alarm(1,dwellTime,0,function()
      coilOff()
    end)  
end)

Now finally a picture of the ESP8266 generating ignition pulses. Sorry my inadaquate photographic equipment doesn’t show the actual spark:

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I should be there - Wed 6th I was still returning from Sydney.

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OH: A reminder to post a pic or two of the meetup if anyone thinks of it! You might not think there’s anything interesting to take a picture of, but I promise you anything you can share of devices, instruments, wires, people, whiteboards, arguments, mess - it all makes our twitter feed more interesting and shows potential members what exactly it is that we get up to :smiley:

Note: even though we’re probably considered a public space [?], please be courteous and give everyone a chance to step out of the picture if they want to.

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Pics next time I guess.

It was nice catching up with everybody again.

I wouldn’t mind coming down again for Wednesday 27-01-15 if it’s on again.

@eyal was talking about running the esp8266 on solar power, and I’ve been thinking about that too. In fact more than that I have a whole lot of small solar-panels and I’m going to be purchasing a selection of different specialist regulators this week from element14, which I will bring next time.

I’ve also a big bunch of capacitors salvaged [from various power supplies] that I’m hoping to build in as well.

My theory is to put the capacitors on the solar-cell side of a regulator letting 3.3v trickle out from the regulator to charge the batteries up to 3.3v. Well I will test if it works and bring the results next week.

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Sorry no photos, was busy talking nonsense with various people :smiley:

As far as solar-powered projects go, check out the battery charging circuitry from the Adafruit Feather series, and the Adafruit USB, DC & Solar LiPoly charger. The charger board is $32 from Tronixlabs, but probably uses about $5 worth of components (the rest of the price being the 100% Australia tax, the Adafruit premium, and then the cost of PCB design and assembly). The Adafruit board is basically the MCP73871 reference design.

The key component in the Adafruit charger is the MCP73871, available in several variants from Mouser. The variants are listed on p35 of data sheet, Adafruit use the 2CC variant: 4.2V charge, 6h safety timer, 3.1V Low Battery warning). Mouser price is $3.10, breakpoint at 10 units at $2.86, then at 25 units at $2.38, prices consistent across the range. The component is only available in 20 QFN package.

At $32/unit from Tronixlabs, I would end up putting bigger batteries on my projects and just bringing them inside every now and then to recharge them. $30 per project buys a lot of batteries!

Tronixlabs also stock the Seeed Studios Lipo Rider and Lipo Rider Pro. These are combined solar/USB LiPo charger & USB output. Unless you want 5V regulated to your circuit they’re probably overkill.

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Addendum: Adafruit have a nifty “solar badge” which provides 5V 40mA panel in a round epoxy badge. Might be useful as a mount for small projects. Combine that with a 100mAh LiPo and the MCP73871 and you have a nifty platform for ESP projects (though Adafruit don’t seem to have any 100mAh LiPo in stock).

Futurelec have 3V 225mA panels for $8.90, 120mm x 45mm x 2.5mm. 12cm by 9cm is a bit large for a tiny project though.

Random seller on eBay: 20pcs 5.5V 0.3W 86x38mm PV cells for $36.86 with “free postage” (about 55mA).

Smallest 6V I could find in a few minutes of looking: 80x55x2.5, 0.6W (so about 100mA?)

Or a 43 x 34mm 5V 0.2W at $1.79.

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Sounds like it was a productive meetup! Which is the most important thing. I might be able to drag a friend along (another ESP8266 enthusiast) on a Wednesday with a CTC Black 3D printer at some point, $600 delivered, dual-nozzle.

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We also had a drop-in, interested in electronics and drones. Hopefully our visitor returns in the future!

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