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Post by chrisinkc on Apr 16, 2016 3:32:31 GMT
I am looking to make a couple of nodes using the pro minis. Should I get the 5v or the 3v version? I plan on running some 5v sensors with it so I am assuming I need the 5v version. Can somebody provide a parts list?
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Post by chrisinkc on Apr 16, 2016 3:58:30 GMT
Also, does it matter if I get 16MHz or 8MHz?
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Post by computourist on Apr 16, 2016 12:41:00 GMT
You need the 3.3 volts version to interface to the RFM module. To stay within specs the 3.3 version runs on 8 Mhz.
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Post by chrisinkc on Apr 16, 2016 14:44:22 GMT
What if I need to power a 5v sensor? I thought most people using the minis were getting the 5v versions and then using a regulator to knock it down to 3.3v for the RFM module.
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kmac
New Member
Posts: 30
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Post by kmac on Apr 16, 2016 17:24:05 GMT
I use the 3.3v 8Mhz minis. I use a supply power of 5v since the 3.3v minis have their own regulator. Then I tap off the supply power for any 5v needs.
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Post by computourist on Apr 17, 2016 11:18:11 GMT
Have a look at the maximum specs. The RFM module can not cope with more than 3.6 volts on its inputs. If you connect an RFM69 to a 5 Volts Arduino's SPI signals (even with a 3.3 Volts power supply for the RFM) it will get 5 Volts at its inputs and be damaged.
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Post by chrisinkc on Apr 22, 2016 2:14:01 GMT
Computourist, can you post the wiring schematic that you use for your pro mini nodes?
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Post by computourist on Apr 23, 2016 11:19:21 GMT
Hi chrisinkc, Schematics for pro mini are on my github.
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mova
New Member
Posts: 9
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Post by mova on May 16, 2016 10:13:57 GMT
Have a look at the maximum specs. The RFM module can not cope with more than 3.6 volts on its inputs. If you connect an RFM69 to a 5 Volts Arduino's SPI signals (even with a 3.3 Volts power supply for the RFM) it will get 5 Volts at its inputs and be damaged. Just a quick question. Does what you say here mean that what i've done is just to fry my RFM69HW? I've used an Uno compatible with an ethernet shield on top and i'm having trouble making connection between my gateway and end node
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Post by computourist on May 16, 2016 10:19:37 GMT
As stated: the RFM module can not tolerate 5 Volts at its input. By applying 5 Volts you probably damaged the module.
The most sensible way around this is to use an 3.3 / 5 Volt selectable Arduino, like Buono or Pro mini 3.3 V
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mova
New Member
Posts: 9
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Post by mova on May 16, 2016 10:59:57 GMT
Dammit. But hey at least I now know why things aren't working. I had the gateway connect nicely to MQTT but no node connection.
I'll set out to buy some 3.3v pro minis asap but can you tell me if/how I can use the W5100 shield from before (pic above) on a pro mini? Is it the same W5100 you use in your gateway 2.4 or should I buy something else?
And by the way thanks for your work Computourist! I've come a long way in 5 days by reading yours and Papas posts
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Post by computourist on May 16, 2016 11:28:44 GMT
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