cool little thermostat for your project

[chase4food]

I came across this nifty little programmable thermostatic controller today. I have a circulation fan built for my James Cook to cool the van interior when parked in the sun. Problem is the low power computer fan runs day and night unless I manually turn it on and off which requires open and closing the sliding door. I have meant to built a microcontroller and program it so it will turn on the fan when the interior temperature reaches a preset level.

This little board is under $4 shipped. Cheaper than I can buy a PIC microcontroller.

http://amzn.com/B00GWFK7FA

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- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[Zeitgeist 13]

Ha! I've been meaning to use computer fans in the rear quarter window vents for this very purpose. Nice find
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[chase4food]

[chase4food]

For those want a more plug and play and don't mind the space need to mount it, this is an alternative with housing. It draws max of 250mA, however. I suspect the little board draw less, or I can hack out the relay to save some power.

http://amzn.com/B019I3YCFS

You can use it as thermostat, I think, for your Propex if you fancy.
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- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[chase4food]

Wanting an excuse to go for a drive in Isolde, I went to Fry's to shop for a large and quiet computer fan. I have been planning a design for an extractor fan for mounting onto the skylight as a circulator to keep the cabin cool when parked in summery sun. Heat is bad for just about anything, and in Westfalia the cabinet plastic molding shrinks and deteriorates.

I had built such a fan for my James Cook

http://eat-drink-men-women.blogspot.com/2012/09/ventilation-fan-preliminary-version.html

eat your hearts out

always fun to go electronics shopping

these are what I am here for

the finalists - the one with the white blades is more expensive, but quieter and lower CFM

It was a tough choice as I was extremely concern about the noise trading off adequate CFM.

quality won the day, I chose the higher CFM and cheaper fan that obvious has better quality

I was concern that it may not be too happy operating in this orientation

It turns out it seems to be quite at home in this orientation - pulling air upwards out through the skylight.

12.5V represents battery voltage while parked

draws 222mA

the fan comes with a nice extension cable with detachable connectors so would be perfect to make the extractor fan stowable when not in use

I plan to integrate the programmable thermostatic controller into the fan assembly. It will however take some time to arrive via slow boat from China. So far the financial damage of the project is $17.

More to come as I fashion a support for it.

my blog post:
http://eat-drink-men-women.blogspot.com/2016/03/in-good-shape-isolde-part-11.html
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- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[Gnarlodious]

I bought one of these (top photo) and played with it just now. Slight irritation, it can only display centigrade degrees. Also, the readout cannot be shut off, so it will consume power even while idling and when you don’t care to see the bright red numbers. Blue would have been more comforting for campervans, but they don’t make one.

The indicator LED is also bright red, which adds to the bright redness of the digits. Not exactly stealthy.

Also, the sensor is sort of short. Because it is a sensor, splicing extension wires may not be a good idea.

At this price, I can chuck it in e-waste and buy a fahrenheit model. It looks like there is no model that has a darkenable display.

Documentation here: http://www.mpja.com/download/32184mp.pdf
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[chase4food]

[chase4food]

Any chance you can measure the current the board consumes, with the relay energize? You have the duty of community service as you are one that has it.
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- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[Gnarlodious]

Fluke 117 says 68mA with the relay engaged, 18mA idling. Not too bad, actually! Good guess on the relay power.
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[chase4food]

[Gnarlodious]

Not really relevant for me because I will run a 7 amp electric blanket on it while plugged in to shore power. The dimming resistor is a good idea though, but for that much work I think I’d go for a fahrenheit model with a longer sensor wire:
http://www.ebay.com/itm/151331886632

Then I would replace the red digits with blue ones. When I run out of projects
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[PDXWesty]

I don't mean to be a simpleton, but why can't I just buy a $10 12-volt Honeywell thermostat and be done with it? Off the shelf product and I don't need an electronics degree to hook it up, build a housing or mess with some plc controller. Am I missing something?

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89 Westy 2.1 Auto

[chase4food]