HeaterMeter on the Raspberry Pi Model A+


 
I've been playing with the A+ and love the fact that you can now hide the wifi adapter in the case. The HM looks even more polished now. I just the snipped unused pins off of the pi GPIO so I could use the A+ with my existing HM4.2.4 boards without changing out any of the resistors, buzzer, etc.

Bryan, pardon my EE ignorance but is it even a possibility that an extra RJ45 can be added to the HM board and then routed through the GPIO of the pi to add wired LAN support for those who want it? It would be great to continue to capitalize on the reduced size of the A+.
 
Maybe unrelated, but about a year and a half ago, sandisk had a bunch of problems. I got 2. Class 10 MicroSD that crapped out after a couple weeks. I could format & write to them, but after a bit they would show as unformatted. It wasn't a problem to get them replaced. It didn't happen if I left it in a PC, just phone & I believe Linux devices were affected as well. Didn't test.
 
Tom Kole said:
Bryan, pardon my EE ignorance but is it even a possibility that an extra RJ45 can be added to the HM board and then routed through the GPIO of the pi to add wired LAN support for those who want it? It would be great to continue to capitalize on the reduced size of the A+.
Click to expand...
No unfortunately the Ethernet is a separate chip that's on the Pi board which isn't there if you're using an A/A+. It's actually a USB hub with an Ethernet chip built into it that then takes over the CPU's one USB input completely.
 
what pins does the A+ connect to the HM with. I want to think that's the first pins connect to the HM and the offset is towards the alarm, is that correct and I will just clip off the unused pins like Tom.
 
John Bostwick said:
what pins does the A+ connect to the HM with. I want to think that's the first pins connect to the HM and the offset is towards the alarm, is that correct and I will just clip off the unused pins like Tom.
Click to expand...

Yah, you got that right... The A+ mates to the HM just like the B model, except the header on the A+ has more pins, the extra pins are beyond the HM connector on the side where the alarm is on the HM board. The board I setup to use the A+ didn't have an alarm buzzer installed on it anyway, the transistor there did interfere and had to be moved to the other side of the board, the resistor didn't interfere so I left it (and the extra pins) alone.... So have to move the buzzer and transistor for sure, and that resistor if for some reason it hits the extra rPi pins, or clip the extra pins....
 
I kinda figured out my question to my last post about what GPIO pins to use. I received a couple of B+ boards from a mistake in a companies webpage showing the a pic and stating they were B version.

Anyways, looking at the boards and I know most would not remove components to make them work with the HM, but could we remove the USB port that interferes with HM when you connect them together. I know cases would not work though and so you would definitely need away to protect it.
 
If you manage to get your B+ mated to the HMv4.2 I could modify my case to fit it, but the USB and LAN ports would be recesses in the case a bit because the B+ doesn't line up with the edge of the HM board the way the model B does...

PS if you attempt this make sure you cover over the LED solder joints and those resistors in that area to isolate them from the USB header, cause I'm pretty sure the metal USB housing will short all that stuff out when you mate the boards...
 
I spent several hours trying new B+ designs yesterday. There is absolutely no way to make a B+ fit a v4.2.

Everything that is changed causes a problem! The new USB jacks hit the our plugs, the moved USB jack occupies the same space as our LEDs, the Rpi header moved to the left means the LCD doesn't fit either. This extra IO pins also hit the alarm but that's easy to fix with some wire cutters :-D
 
Bryan Mayland said:
I spent several hours trying new B+ designs yesterday. There is absolutely no way to make a B+ fit a v4.2.

Everything that is changed causes a problem! The new USB jacks hit the our plugs, the moved USB jack occupies the same space as our LEDs, the Rpi header moved to the left means the LCD doesn't fit either. This extra IO pins also hit the alarm but that's easy to fix with some wire cutters :-D
Click to expand...

So lets stick with the A+ :)
 
Tom have you had any problems with your A+ maintaining a wireless connection? My A+ test the wifi stops working after 8-10 hours of sitting when connected to 12V. It works ok for days if I hook it to my bench power supply at 5V. I am wondering if the lower power draw of the A+ makes our 5V regulator not able to handle a wifi transmit because of the spike in power usage. I'd say it was the cheapo wifi adapter but running on 5V it is fine so that points to something in my 12V->5V setup. Have you had an similar dropouts?

I am planning to hook it to the oscilloscope and see if I can detect any droop.
 
Bryan Mayland said:
Tom have you had any problems with your A+ maintaining a wireless connection? My A+ test the wifi stops working after 8-10 hours of sitting when connected to 12V. It works ok for days if I hook it to my bench power supply at 5V. I am wondering if the lower power draw of the A+ makes our 5V regulator not able to handle a wifi transmit because of the spike in power usage. I'd say it was the cheapo wifi adapter but running on 5V it is fine so that points to something in my 12V->5V setup. Have you had an similar dropouts?

I am planning to hook it to the oscilloscope and see if I can detect any droop.
Click to expand...

ugg this is not good, hopefully its something that can be an easy fix or points to the adapter.
 
I haven't noticed this but my experience is fairly limited. I'll set it up to run tonight indefinitely and will post a link.
 
Bryan Mayland said:
Tom have you had any problems with your A+ maintaining a wireless connection? My A+ test the wifi stops working after 8-10 hours of sitting when connected to 12V. It works ok for days if I hook it to my bench power supply at 5V. I am wondering if the lower power draw of the A+ makes our 5V regulator not able to handle a wifi transmit because of the spike in power usage. I'd say it was the cheapo wifi adapter but running on 5V it is fine so that points to something in my 12V->5V setup. Have you had an similar dropouts?

I am planning to hook it to the oscilloscope and see if I can detect any droop.
Click to expand...

I'd also be interested to see if restarting the networking stack is able to bring it back online.
 
Yeah that's why I was trying to hook it up to a keyboard so I could at least type some commands and see if it was not locked up completely. But when the wifi is plugged into an external USB3 hub with a giant power supply it works for at least 12 hours over the weekend. I tried with just a monitor but the display goes to sleep.
 
Yeah I've spent the past 2 hours with jumper cables on the Pi A+'s USB port watching the voltage. With the 12V power adapter I see less that 0.060V of droop lasting less than 100uS. USB spec says you can go down to 0.250V of droop and still be in spec. Connected to the bench power supply I actually see slightly longer drops of the same duration. I'm not sure why the 12V supply would work any worse than the 5V supply.


I swapped out the wifi adapter (with my original adapter!) and let's see that happens over time.
 
Well, left the A+ running... when I got back to look at it after ~13 hours it was not responding.... Looking at my router I no longer see it in the device list (until I reboot)... Not sure what that proves other than the A+ seems to crap out after some hours. If there is any specific testing I can do to help just let me know....
 
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