here is the LD-29 MCU pinout (eg how to put your ATtiny13A in there...)

@ wight & WarHawk-AVG

Yep, it is totally cool! it is so easy doing mods with such prices.

@ImA4Wheelr

No problem :slight_smile: It might be a nice project!
you may also use a reed switch instead of a clicky switch, it might be cooler - that’s what I plan to play with.
I have ordered some more components and LD-29.
I’ll try to make a nice mod when I receive it. H)

:slight_smile: I’m going for ‘dropin’. If we had to use jumper wires I’d just stick w/ a tiny10. You do have to file each one down. Once I had the non-functional v04’s in hand I filed down all 4 edges.

Thanks guys. I must have been not in my right mind when I did v04 of the adapter board. Hopefully I’m in my right mind now. :wink: I’ve reviewed the board a couple of times and it v06 continues to look right, so I think we’re OK.

Since this PCB does not expose any of the bottom leads to your soldering iron I consider it similar to a MLF package. In my opinion the best way to install these is going to be hot air reflow onto a clean PIC landing pattern. Use desoldering braid to clean up all the old solder, then apply solder past, then reflow the PCB into position.

I was reviewing the pinout just now to do the required STAR firmware modifications and realized that there’s a small problem with the adapter PCB for this application. The offtime cap is on pin 6, which the adapter brings straight through (to pin 6 on the ATtiny13A). Unfortunately there is not an ADC on that pin, it cannot be used for offtime.

Also, it seems that hardware PWM is only available on Pin #’s 5 & 6! Lucky for us #5 is the PWM pin.

For the LD-29 Pin #2 is NC, so hooking the ATtiny up to that pin doesn’t do anything. Instead we’ll move Pin2 on the attiny to the #6 position on the PCB and not worry about losing any features. At this point the board is getting a little crowded:

Damn I ordered 6 of the v6’s literally 10 minutes ago!

Still should work or no?

Yeah, I expect it to work fine. You just can’t use the integrated offtime cap unless you do an airwire from Pin 2 to Pin 6.

Here is the v07 from the previous post - OSH Park ~

So I would wire a cap to the ATTiny pin2 (or just a jumper wire from pin2 to pin6 to use the on board cap)?

And this uses stock off-time FW or the ports need changed?

Thx

FW needs mods. I was planning to work on them tonight but haven’t gotten around to it yet. PWM out must change pins, ADC changes are needed for LVP.

Yes, you could just wire up the cap as you described.

I’m not 100% positive that we can easily do the offtime cap & battery monitoring at the same time using the stock setup, but we’ll see once I wade into it. The offtime cap needs to be compared against a lower reference voltage than Vcc, so we normally compare it to the 1.1v internal ref. The battery monitoring voltage divider needs to get compared to Vcc. We’ll see how that pans out! I think it will be OK.

Oops, this is just me being crazy again! Totally insane. The ADC doesn’t return a boolean value (maybe the comparator does?). The code is already fine to do both. Ugh, the things I say sometimes. The only thing we need to tweak is voltage we compare against and all the values.

Note to self: divider gives 1.2v @ 6v input

Well, I’ve gotten mixed results from the first offtime firmware effort. I should have done it in stages, but I made all my changes at once. Oops.

I changed everything I mentioned before:

  1. moved PWM pin from 5 to 4
  2. added RUN_PIN on pin 3
  3. changed ADC reference from the internal 1.1v ref to Vcc (2.48v or 2.50v or something :wink: )
  4. changed LVP values

Please review my changes here.

Oops, I see a problem already - I didn’t remove the STAR2_PIN = PB0 define from the code. I’m not sure if that’s causing any problems, but we are using PB0 for something else. I can’t imagine that it’s doing anything good.

The firmware fires up and runs the driver at 100% duty cycle but does not successfully change modes at all, ever. I even shorted VCC to PB3 using my tweezers and then cycled power to the driver a couple of times. I could not get it to change modes. Hopefully this is due to my mistake with the PWM output pin?

C_K wrote:

Damn I ordered 6 of the v6’s literally 10 minutes ago!

Still should work or no?

Contact OSH Park and ask them to subsitute in v07. I've done it before. They were really friendly and happy to accommodate.

Wight I can air wire a 13A in and start on the coding with you but if I order an LD-29 from fasttech I’ll be waiting a month+, I have the worst luck with their shipping every single time I use them. Do you have a spare I can buy from you for testing purposes so I don’t have to sit around waiting?

I went ahead and ordered 6 v07’s I’m not concerns about asking them to swap them out for $.80. It’s not worth Lean’s time even tho I know he’d do it so I’m not even gonna ask.

Unfortunately I’m not in much better shape than you. I only have 1 available to work on currently. And I just lifted a pad on that one! It still works, but I need to be more careful. If I was in better shape we’d get you hooked up. Be sure to spend the extra few cents on USPS First-Class. I always do on FT orders. For a single LD29 it’s $1.44, for two LD29’s it’s $0.88, and for 4x LD29’s it’s free anyway…

I know what you mean. When we’re talking about <$3 for PCBs I try to order as soon as I suspect the layout might be ready to go. If it turns out I’m wrong, well. … sad face: I just re-order. It’s worth it to me to speed up the time to have them in hand and possibly learn that changes need to be made. At least that’s what I keep telling myself. How’s your Eagle learning process going?

For the record when I was testing yesterday I noticed that the driver gets plenty hot. Regardless of whether the components can handle it, I’d pot the thing for sure.

In addition to what Cereal_killer said, note that OSHPark is totally rolling right now. From what I’ve seen they are doing 2-4 panels per day currently, so when you order you’d only have a tiny window to ask them to do manual corrections for you.

Was just trying to offer a friendly solution. C_K seemed upset about just ordering v06. No good deed goes . . .

That was just an FYI, not a reprimand! :slight_smile:

Did you notice what components got hot?

I was doing other stuff, so I did not pay close attention to that. I only worked on the bottom side. On the bottom side, it seemed to me that the FET and sense resistor both got hot. The sense resistor became hot faster I think.

:~ strange, both of the FETs’ are rated >8A on their datasheets.
I assume that it should’nt get really hot on ~2.8A ;\

[quote=HiTiT]
:~ strange, both of the FETs’ are rated >8A on their datasheets.
I assume that it should’nt get really hot on ~2.8A ;\/quote] I was working on measuring other stuff. Soon I’ll take a closer look at where the heat is really coming from.

I’d say that at 100% duty cycle this driver produces a good bit more than 2.8A out, although I have not measured. Probably around 3.5A+ output. The input at 8.2v (IIRC) was ~1.85A. That’s 15.17W input, so make whatever efficiency assumptions you want (80-90%) and figure the output based on that.