I completely missed that it uses an attiny.
I was just looking for a good 3 cell buck driver, and here you come.
Do any of you have any tips on how to solder double sided boards?
The hardcore way is solder paste with different melting points. The way I do it is to use just enough heat to melt the side you're soldering. The other side should stay solid as the PCB acts as a heat shield.
Other than that...trial and error?
I use Mattaus' approach to. Even if the other side goes liquid, surface tension keeps the pieces on the other in place if the board is some what level. Well, as long as you don't jar (tap) the board.
I reflow one sand, hand solder the other side.
I just received some version 3 boards. There is a minor, non-functional mistake. You can't see it on the OSHPark renders (they can't render this text for some reason) but the name "Knuckle Head V1.0" appears on the board. It never clicked for me to change it to 3.0 because I turned the silk layer off when doing my final check. The CAM processor still includes it, and because OSHPark did not render it, I never saw the mistake when confirming the order.
So if you get boards that say V1.0, they are V3.0 boards.
I'll correct the file tonight and update the links above.
- Matt
I received a different version I created for a specific light. Please ignore above.
The email I got from OshPark shows pics of front and back, plainly marked V3.0
They’re supposed to be leaving fabrication, should see them this week…
You are 100% correct. The version I received was a special 20mm sized one I created for a custom drop-in. I forgot all about it lol.
It's Monday morning and my first day back at work in 10 days. It's raining, getting colder, and I think I left my brain in bed.
Time to call in sick and head home to collect it.
Ran some numbers on a gb and at 25 sets the price break is 20% or$9 instead of $11. The biggest likely savings will come from shipping wher the minimum cost on each order is $3-$5 but only $5-$6 for 25. This savings will be realized if repackaging and postage can be kept to first class postage rates for the individual sets. At only 10 sets I don’t think it’s worth the effort and the next price break is at 100. IF postage can be minimal, savings on 1 set including postage could be ~35%.
So is this for parts and PCBs required to build your own? Is this using the Digikey cart (which I have now added to the OP)?
I copied the digikey cart from the Oshpark thread into that op and did not include the boards or inductor. One shipment of 25 sets, the shipping is only ~$5-$6 instead of 25 times $3-$4. That plus a couple bucks per set volume discount less whatever it costs to reship. I’m thinking this is more of a preliminary test so 25 seems reasonable. If you want to go for more the price gets a bit better but not until you hit 100. Maybe mouser has different price breaks?
From memory mouser does not sell the voltage regulator I specified. If people can find a different one using the same footprint then go for gold, although note that the regulator I chose can convert the entire input voltage (up to and above 18V) down to 3.3V. Finding a linear regulator with such a wide operating voltage that used minimal external components was tricky. I guess that's why it's the most expensive part on the board!
What is the advantage of a buck boost driver for an XML2 or for an MTG2 over one of the FET drivers other than it’s really very cool? I desperately want to make one but haven’t the foggiest notion why.
Edit because the darn iPhone changes what I write.
Well for starters this is just a buck driver, so it's even more similar to the FET drivers!
The main advantage is efficiency. With the FET drivers, you're getting high power but the efficiency is somewhere between sh*t and horrible. Like less than 70%. With this driver it's up and over 90%. As a result you get longer run times, cooler running hardware and prolonged component life; including the LED which is now not seeing peak current limits constantly being smashed.
If you just want bright light, stick with the FETs. They're a damn sight simpler and can take more punishment as a result.
- Matt
Thanks for that explanation. I like it. A FET driver for lights that are like dragsters going all out for a short time and a Knuckle Buck for a workhorse.
So, FET’s are old beaters and the buck driver is a classy night out on the town sort of ride? ( don’t think I’m gonna mention that to my old beaters, shhhh )
Might want to refer to them as nitro hotrods. At least when they are within ear shot.
This inductor should be interchangeable, there's usually some wiggle room in the specs of these things anyway. As long as it's close, and fits on the board, it should work. --> http://www.ebay.com/itm/160660596570
Also, bookmark this store. Has great prices on surplus stuff like that. http://stores.ebay.com/RF-Basic-Store
scottyhazzard wrote:
Thanks for that explanation. I like it. A FET driver for lights that are like dragsters going all out for a short time and a Knuckle Buck for a workhorse.
Not sure that is the best analogy. Since you can not provide more voltage than the Vf of the emitter (1S for xml,etc and 2S for MT-G2), the cell may be going all out, but the emitter isn't. So the dragster's performance is limited (e.g. low pressure fuel pump).
A high current buck is needed for a real "dragster" light.
Exactly.