V3 Tricopter Flip of Death

[x0054]

Yep, it's the MPU, I am pretty sure about it. I got it really dialed in with the AfroMini. I don't want to ditch the integrated board, but another MPU is $10 on DigiKey. Once I factor in that I have to get a reflow station and stuff, it might be much cheeper to just purchase another FC. I can't really fault quality control too much here, because it did work fine for 1.5 battery packs, and then started to glitch. But on the other hand, I need a reflow station for other purposes. Hmm....

Replacing it isn't terribly difficult. You basically heat up the chip using the reflow gun (basically heat controlled high temperature heat gun with a tiny nozzle) and lift it up with tweezers. Then you apply some solder past to the pads, lace the new chip on the board, and heat it up for 30 seconds or so. I have done it before with a barometer and it worked fine. I am pretty sure DigiKey will send me a high quality par. Still, at $10 it's kind of annoying, considering that the entire board is $35. When you buy these things in bulk, the price goes down to ~$5 per.

- Bogdan

 

[cranialrectosis]

Sorry man. I was hoping it was a bit of crap in a motor causing some vibe.

Good thing you had the Afro mini around.

 

[jhitesma]

Could always get a cheaper MPU off aliexpress.

I could send you one of the dead Naze's I have...the MPU should be fine on one and might be ok on the other (why I haven't tossed them yet.)

You could just get a MPU breakout on ebay for a couple bucks and take it off of there (I've used cheap ebay ones with no problem.)

Instead of a toaster oven you could do a single chip with just a heat gun. I've done similar components with a $7 embossing gun from the fabric store. Have to be careful, it's easy to knock other components loose...but it can be done.

 

[x0054]

Hmm, good idea jhitesma, but I have to wonder. If the cheapest I can buy just the MPU-6050 it self is $5 from DigiKey, how can the people selling breakout boards on ebay afford to sell them for $3? Did some of these chips fall off a truck some place in China

In any case, that's a good idea, I picked up a breakout board for under $5 with shipping. So we shell see what happens.

- Bogdan

 

[jhitesma]

Digikey isn't always the cheapest, but they are reliable and fast which is worth the price difference to a lot of people.

It's also possible that some of the ultra cheap ones are either seconds, or clones, or most likely refurbs pulled from recycled cell phones and cleaned up.

But considering that even Digikey sells the exact same part at prices ranging from $4.20 to over $10 depending on the quantity there's obviously a lot of wiggle room on pricing.

I've bought a couple of the $3 boards off ebay and never had any issues with them. In fact the only boards I've had that I've questioned the MPU-6050 on are official Naze32's bought directly from TC (though I'm still not convinced it's the MPU on any of them.)

It's worth remembering that these aren't solid state devices in the traditional sense. They're MEMS - tiny mechanical machines. There are actual moving parts in there that can be damaged. They're rated for 10,000g's for 0.2ms while unpowered. But that doesn't say much about how many crashes the'd survive while powered - much lower forces for longer times may do more damage.