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Story: The Weather Outside Is Frightful (Or Is It?)Total Replies: 3
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dotmatrix

Feb 04, 2017
10:43 PM EST 		Holy Hairless Cats Batman! That's one expensive over engineered thingie!

At the very least swap out the TS7680 with a RPi and a USB to RS232 cable. That will shave about $150 directly off the hardware.

If the entire project is inside a home, you can eliminate the industrial thermocouples - no need to measure above 100 C... and replace those with simple $2.63 sensors connected to an inexpensive Arduino board... or if you are 'good' at electronics, just the AVR on the board. The Atmel AVRs have ADC on the chip... just hook your cheap $2.63 temperature sensor to the AVR and program it to poll the ADC. Output the ADC reading to your RPi...

And then Bam! you've changed a $500.00 project into a $50.00 project.

Temperature Sensor:

http://www.digikey.com/product-detail/en/texas-instruments/L...

$2.63

AVR with 6 ADC channels (very easy to just hook one sensor per ADC -which is still overkill):

http://www.digikey.com/product-detail/en/microchip-technolog...

$3.01

**************

$35.00 for RPi with Ethernet... or $5.00 + $35.00 for RPi Zero and USB Wifi

So... about $50 in parts, and a little bit of extra programming rather than:

$203 for the SBC

$275 for the Temperature sensor ADC
penguinist

Feb 05, 2017
12:15 AM EST 		I'm with you dotmatrix, the RPi solution works great. A DHT22 temperature/humidity sensor is only a simple three wire connection (power/ground/gpio input) with no ADC required, and I find myself just tacking one onto many/most of my RPi deployments just so I have a variety of sense points inside and outside the house.
dotmatrix

Feb 05, 2017
10:53 AM EST 		>A DHT22 temperature/humidity sensor

Thanks for the tip!

It costs $9.50 on my favorite electronics source... digikey:

http://www.digikey.com/product-detail/en/dfrobot/SEN0137/173...

*** Please note: This is not an advertisement. I do not work for digikey. I also purchase from Jameco:

http://www.jameco.com/webapp/wcs/stores/servlet/StoreCatalog...

Over the years, I've found that purchasing the 'Electronic Kits' from Jameco keep me stocked with standard parts. However, Digikey seems to have higher quality components overall... and, of course, a much wider selection.

However, I always seem to forget what I have in my parts buckets. I've been meaning to write a simple inventory application... but am generally not great at updating inventory numbers anyway.
cr

Feb 05, 2017
5:58 PM EST 		@dotmatrix: see https://www.partkeepr.org/ ...Run that on a server in your office and access it from a laptop in the lab?

I tend to buy from Mouser and AllElectronics. I'm still at the spreadsheets stage of inventory control, myself, but partkeepr is in the Round Tuit file.

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