iSpindel - digital WiFi hydrometer

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eyuptm said:
Welcome back tomos, hope everything has calmed down now... I'd be happy to have a couple more PCBs and tubes off you, and any other components you have to build another couple of ispindels!! Nice to have you back!!
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Hi, they have all gone now I'm afraid they were snapped up as soon as I posted. All good here this end apart from unable to do any brews as it's in my dads shed so I've been building arcade machines!
 

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I wonder if anyone using the iSpindel with Unidots, has added a alcohol graph to their Ubidots graph page? It would need to be calculated within Ubidots, based on the starting SG and the present SG.

It's a week or so now, since my, supervised for the first time by the iSpindel completed. I deliberately left the iSpindel running and reporting to Ubidots, just to see how the battery would last out - its doing fine and I have now transferred it to tap water, to check how well my calibration held up. It is absolutely spot on - showing .0998 SG. The temperature reported by the iSpindel initially seemed to be around 1.5C higher than actual temperature. That error now seems to have gone and it is now accurately reporting the correct temperature.
 
How long has the battery lasted for, and with what reporting interval?
I wondered about an abv graph, but didn't see much point. I think a better option would be to set an event to trigger when the SG hits a desired level, so you don't have to keep watch. Altho I prob would anyway!
Those measurements sounds spot on... And I find my temp fairly accurate too.
 
I don't yet know how long it will last, because its still going strong. It is reporting in every 15 minutes, continueously for the past 17 days. I gave the new 3400mA battery a full charge before turning it on and its still reporting a very respectable 4.080v - which I know is accurate, because I checked the voltage calibration against my own 4 digit meter after I had built it. It still has a long way to go yet, because my dry dummy run suggests it will continue to work until around 2.5v.

I did try setting a couple of events to send SMS messages, but they didn't work - no SMS received.

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Above is my SG graph, up to today. It rises up from the initial 1.080 it started at, then began the steady drop in SG to flat line 4th/5th June. The sudden, dramatic dips in the SG, are where I gave the FV a good shake up. 5th June on is where the Ispindel is just laid down out of the FV. The sharp steps in the graph are where it's been moved.13th June I put it in a jug of tap water, to recheck the calibration. It settled today at a precise 1.000
 
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The protection circuit on the ispindel should cut the battery at 2.5V as they shouldnt be drained below that. I'm not sure if its a linear drop to there though ?
I found webhooks on ubidots fairly reliable - never tried SMS.
 
Here is the battery voltage graph. The graph show a steep initial fall in voltage, then it becomes less steep..

The steps are due to the sensor input sensor having limited resolution of 0.005v by the looks of it.

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gingerneil said:
Mine is calibrated at all... It just falls off a cliff. Is there a guide to get the right settings in the config?
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Right settings for what? If you mean the voltage calibration, there is a factor in the iSpindel's calibration screen, to adjust that. You will need an accurate voltmeter to check the voltage, whilst at the same time check what the iSpindel is actually reporting as the battery voltage. Mine was spot on using the default value of 191.8 - if yours is wrong, then you can use the following formula to work out the correct factor...

((Voltage reported by the iSpindel) / (the voltage of the battery as measured with a meter)) x the current factor (191.8)

If your battery voltage is 'falling off a cliff', might it be a fake 18650? There are lots of them about.
 
Thanks - I'll check the voltage. I have a multi-meter, but not sure on the accuracy.
I bought my 18650 from a UK supplier and its a samsung 30Q. It runs for 10 days or so, then drops to nothing according to the ispindel very quickly - maybe over 4 hours. Fully charged, ubidots reports it at 5.339v - so a good chance something is wrong somewhere!

Edit.... a little digging, and it turns out I have 220 Ohm and not 220k Ohm resistors. @tommos76 did mention something when he sent the boards, but I forgot to look! Seems I need to get my soldering iron out!
 
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gingerneil said:
Edit.... a little digging, and it turns out I have 220 Ohm and not 220k Ohm resistors. @tommos76 did mention something when he sent the boards, but I forgot to look! Seems I need to get my soldering iron out!
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The reported voltage, has no bearing on how long it is able to send its data, so I would suspect that battery. Torchy in the UK, as a source is well recommended, they have a good reputation.

From memory of the circuit, I think the resistors set the reported voltage - get those wrong and you will get wild values.
 
OK - makes sense. I stuck the PCB into the pet using sugru, so not sure if I will be able to get it out without destroying everything. It usually runs for about 10 days, but thats right on the edge of brew time, especially if dry hopping. The latest firmware is now usable after a few smalls fixes (I finally actually contributed to the git!) and that should improve battery too. I'll change the resistor in the ones I am building so they report properly, and I'm now using 18650.uk direct for batteries - so they should be ok.
 
One of the likely reasons you're not getting a long run time is that 220Ohm resistor in the voltage divider. There's now a 5kOhm load across it all the time, rather than the 230kOhm. If you can get it out without damage it would be well worth it!
 
Without recharging the iSpindel, because it still had a good level of charge remaining from fermenting my 5gall of wine (begun 20 days ago), I started a 5gall batch of Wilko Geordie Scottish Export on Wednesday. The fermentation went ahead well, until yesterday lunch (24 hours later), when it had almost stalled as the temperature dropped to 18C as the weather cooled down.

So I lifted the FV onto my temperature controlled heater pad, set to 21.5C. Once the temperature had equalised by late afternoon, the fermentation got going again. The beer brewing seems much more sensitive to temperature than wine fermentation.
 
Well this looks very, very cool.

I'm a software dev by trade, so looking for ways to combine my skills there with this new hobby, though without making it seem too much like work.

I've already hacked together my homebrew version of the inkbird fridge controller, this would be ideal to integrate with that for more accurate temperature control.

I don't have a 3D printer and the PCBs look more efficient to bulk buy so I'd be keen to get in touch with anyone who is geared up to supply one or two.
 
The bits are fairly easy to get hold of - but the price is quite high if buying one or two from UK suppliers. That's why I've ended up with some to sell... not sure how many posts you need to be able to message... but I think admins would rather keep sales etc to messages rather than me just posting my email address! Mine don't use the plastic sleds - the PCBs fit nicely in the pets without needing the plastic around them. I added a little sugru for ballast, but not sure it's even needed.
Drop me a line when you can.
 
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