mating HM4.1 to rpi b


 
J

JonS

New member
Hey yall,

I'm putting together my first HMv4.1 using a Raspberry Pi B (model 756-8308), but it looks like the ethernet jack on the rpi is getting in the way of the edge of the LCD, so the rpi cannot be fully placed in its socket. It can still get in far enough to function, but it's prone to pushing itself out and also doesn't fit in the case. I did use a different color of LCD (the black on white one) but it appears they're the same dimensions as the default green, so I don't think that's the problem.

It's definitely possible I did something wrong. If anyone has any suggestions on how to resolve it I'd appreciate it. The only thing I can think of is getting an rpi A and moving the sdcard over. I tried searching the boards for a while and didn't see anything similar mentioned.

Here are pictures of what I'm talking about:
http://imgur.com/a/OozPN

Thanks!
Jon
 
Yeah of course Tom, I just added some more to the album with a side view so you can see the HM/Rpi header connection and each board separately.
 
What is the height of the 2x13 header you are using to connect to the pi? Is the LCD sitting flush against the pin header on the HM, parallel to the board?
 
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The header is the "alt Mouser" one it looks like, which is 7mm high vs the recommended 8.5mm version. I didn't think it would cause that much of an issue though. Is your LCD level or maybe is it tilted down slightly?
 
Bryan you're right, I should have mentioned that in the original post. I got sloppy soldering the button and deformed the original digikey header. I saw there was an alternate one from Mouser so I went with that since they get to me a lot faster -- didn't realize there was a difference.

The LCD's not perfectly level with the board, but it's pretty close. If anything it's tilted away to give the rpi extra room. I added more pictures to the album showing it from the side. The LCD is as close to flush with the header as I'm gonna get it. I think the extra 1.5mm from the recommended rpi header might do the trick, it'd still be pretty close.

I just noticed the rpi audio jack is also hitting the HM board. From what I can tell, my options are
a) take off the audio and ethernet jacks from the current rpi. Not too big of a deal, this rpi's not gonna be used for anything else. Only downside I can see is that changing around network configs in the future would need to be done through console. Not too big of a deal
b) order a new raspberry pi header from digikey and swap them. kind of a pain to remove the current one
c) get a rpi model A, take off the a/v jacks and attach. most expensive but also the least amount of downside and effort involved


Though if anyone has opinions or alternate ideas I'm all ears.
 
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There have been a bunch of HMv4.1 units built and this is the first I have heard of this, so I assume you CAN make it work without going through all that stuff you posted above. I would definately not remove the LAN port from the rPi, the audio either, cause plenty of people (including myself) have the rPi model B mated to a HMv4.1 with only the rPi RCA video port removed.

I don't have any specific suggestions to help you make that header work for you cause I don't use the pin header for the LCD in general. Which brings about an option you may not have thought of.... You can also connect the display using a ribbon cable (floppy disk ribbon will do) instead of directly soldered to the HM board. Or you could just use hookup wire to connect the display to the board. You only need to wire up the first 6 pins from each side of the header, 'cause the 4 pins in the middle aren't used. I've done it both ways (with a floppy ribbon and direct wired) and it works out fine. I just screw the display down to the case to hold it in place, problem solved.....
 
Are you sure the audio connector is hitting the PCB and not a component? Here's an image of my PCB and you see there's some clearance between the connector and the audio jack


And here you can see that the components there should just clear the jack. If they're making contact you might loosen the solder and bend them away a bit. It is really really close but there's plenty of room to clear it and your parts just might be slightly out of line.


EDIT: This is with the regular connector, with the alternate green connector the PCB does touch the HeaterMeter PCB, but the 2x13 connector is just barely not fully seated. The LCD is still above the ethernet jack.
 
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You called it Bryan, the very edge of the audio jack was rubbing up against the edge of one of the BC337 transistors. Nudged it out of the way now everything fits fine. Thanks for yalls time, sorry I was a jackass. Now just need to run the wires for the LED1 and lidmode issues and it should be good to go for smoking tomorrow.
 
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