ESC Firmware Flashing, Part 2

I actually finished this a while ago, I just haven’t got around to updating the blog since then. A lot has happened since I updated it…so let’s get into it.

In Part 2 of the ESC flashing, I’m going to add a couple pics on the hardware side of things. From there, it should be easy enough to figure out how to do the software yourself, with the link to BLHeli I posted in Part 1.

To start the process, take a knife or razor blade and split the shrink wrap open. Do this on the flat side, which has the heat sink, which will help protect the ESC from the knife. Go slow, and it goes pretty quick.
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Each ESC needs three wires (not four, which I soldered on the first ESC). I cut all the wires I needed for the other three ESCs.
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Here’s all four of the speed controllers, with the wires soldered on.
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The three wires were soldered onto a servo connector, because it was handy, and uses three wires. Any lightweight three pin connector will work fine here, though.
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I then made a jumper to my Arduino with a female servo connector and a four pin row of male header pins.
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This four pin header with only three pins connected allows the ESC to connect to ground and pins 12 and 11 on the Arduino using only one connector. Pins 12 and 11 are default, but can be changed to any Arduino pin. Once connected, I ran a test to make sure the solder joints were good, and then flashed the speed controller.
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Finally, you have to shrink wrap, or otherwise protect the ESCs. I choose to use shrink wrap, it’s easy to use. First, cut the wrap to fit over the speed controller.
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Then, with a lighter or torch, shrink it until it fits nice and snug. Keep the heat moving at all times, don’t stop or you’ll melt a hole in the covering. It doesn’t take long, and soon you’ll be done. Who would even know you’ve ever opened it up?
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That’s all there is too it, besides the software.

P.S. If this seems like too much work, there are several places that sell ESCs already flashed with SimonK firmware, and they are only a couple bucks more then buying them stock.

New Soldering Station/ESC Firmware Flashing, Part 1

I mentioned I was going to get a 300W Weller soldering gun for soldering the power wires, and I did, and it was crap. When I powered it up, the tip started smoking and bubbling. Whatever it was coated in, it was not cleaned below the coating (which appeared to be lead or tin). I could have taken off the coating with a wire brush, but why pay for poor quality? Plus, the whole thing felt cheaply constructed. Instead, I sent it back, and ordered the Hakko FX-888 soldering station I’ve been wanting to get for a while now.

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This is what the tip looked like after heating for a short time. It looked worse with continued heating, turning brown and bubbling more.

My Hakko soldering station is 70W, which should be enough to handle almost anything I care to throw at it. It has a nice heft to it, from the transformer inside, and appears to have excellent build quality. The bottom plate is metal, while the sides and top are plastic. It is adjustable from 200°-480°C (400°-900°F), with an on-off switch and a power LED. The LED is somewhat odd in that it only lights when it is heating the element. This means that it will light for about 25 seconds, which is all the time it takes to heat up (at least to 350°C), and after which will only blink occasionally as it slowly pulses the power to keep the tip hot.

The iron holder is made completely of metal, with a built in brass wool tip cleaner, a rubber lip for wiping the tip, and a sponge, allowing multiple ways or preferences for cleaning the tip.
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The iron is lightweight, yet does not feel cheaply made. The power cord is long enough to cover my entire ESD mat.
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The included tip is a 1.7mm chisel tip. I purchased a 5mm chisel tip along with the iron for better conductivity and thermal mass for soldering heat-sucking materials, such as 12 gauge wire.
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Now, we get to the fun part, something relating to my quad. It’s recommended that you use a custom firmware for your ESC’s on your quad, for a number of reasons. The main one is that the motors will have a quicker response, allowing for a smoother flying quad as the controller can correct an imbalance faster. A close second is that it allows the low voltage cut-off to be disabled. Far better you ruin your Li-Po pack by over discharging it then have your quad crash because the low voltage cut-out shut down a motor on you.

The pads are pretty small and close together. If you’re not comfortable soldering on these pads, you can use a rig that you hold on the pads while flashing instead, however, this is a pain, as further firmware updates will then require you to remove the heat shrink from the ESC again. I decided to go ahead and solder them. I have an Arduino, so that is what I will be using. If you do not, it will be easier for you to get the SiLabs Toolstick for flashing instead of using an Arduino.

I thought I needed all four pads, but it turns out I only need three. I will remove the fourth wire before I shrink wrap the ESC again. The wires will terminated in header pins, for ease of future firmware updates or setting adjustments.

The first step is to tin the pads. This was relatively easy.
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Next, I stripped and bent hookup wire at a 90° angle, tinned it, and soldered it in place by heating it up.
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To get a true feeling of the scale of this soldering job, I’ve placed the tip of a medium point ballpoint pen next to the wires, as well as laid the pen next to the ESC.
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Finally, I hooked it up to my Arduino, and successfully flashed the BlHeli firmware onto the ESC.
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How to flash it with an Arduino, and more on the custom firmware, will be covered in a later post. Also, I have the firmware on the Naze32 flight controller updated. Once all four ESCs are in place, testing on the Naze32 begins, at which point the quad will be getting close to its first test fly…

Status Update

Just a really quick update. I know I’m overdue for one, as I said in my last post I would update the next day or so. I’ve been enjoying the holidays and not having school and haven’t been at my place very much to work on it.

I found the last motor mount, which I couldn’t find, so now the forth motor is sitting so the Loctite on the screws holding the newly attached motor mount and propeller mount can cure. I then attached one propeller to another motor and ran it up, and that thing has some thrust. This quad is going to climb like a rocket when it’s done.

Tonight I have some time available, so I plan to research the custom firmware I’m going to flash on my ESCs, and hopefully tomorrow I will start the process of flashing those. If I don’t break the first one, the other three shouldn’t be too hard.

I need a heavier duty soldering iron for soldering multiple 12 gauge wires. I have ordered a 300W Weller soldering gun for this purpose, which will be here Saturday. At that point, I plan on starting to solder the ESCs to a connector. I had a board to split off the wires, but I realized it’s going to get in the way, so I’ve just going to spider-wire the connectors together. This means the ESCs will all be connected together by solder joints; however, I will keep the bullet connectors between the motors and the ESCs

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Construction Continues

In the last post about my quad construction, I built the basic part of the frame, attaching the arms to the plywood plate that makes up the body of the quad. This post continues from there, as I add the motor mounts to the frame.

For the motor mounts, I went to the craft store where I picked up the wood used to make the frame, and picked up a small sheet of 1/4″ thick basswood. I cut out four small squares from the sheet with a miter saw, each a little bigger then the motor mounts. I then marked the center of each with a line in the middle, and did the same on the arms of the quad.

I used the lines to line up the wood motor mount plates, then centered the aluminum motor mounts using the lines and eyeballing. I then held it together with finger pressure while I drilled two holes down through the wood plate and the quad arm, using the metal mount as a guide.

After I drilled the two holes, I marked the arm and the plate with a number and an arrow, so they went back on in the same location, as slight variations while hand drilling can mean a mount drilled on one arm may not fit on another. The holes were then drilled out with a bigger drill bit, to allow an M3 bolt to fit through.

I then glued the wood plates onto the arms, using the metal motor mount, and two M3 nuts and bolts to clamp it in place for about 30 minutes, then removed the bolts so they didn’t get stuck, and let it dry overnight. In the morning, I put the metal bracket back in, and used it to drill out the other two holes, and a hole in the middle for the motor shaft.

At this point, I took my motors and used removable blue locktight to mount the mounting accessory kit to my motors. Well, three of them, anyway. I’m not sure where the fourth kit is, right now.
I know where the mount for the forth motor is, just not the propeller mount, washer, bolt, and the mounting screws.

The mounting plate is mainly held on by the glue, although the bolts do provide a little bit of backup, but the main purpose of the bolts is to hold the motor in place, and allow it to be removed. The nuts are not yet secure, when I balance the motors and props, I will use locktight on the nuts as well. A lose screw or nut could make for a very bad day!

So this is what it looks now. It’s coming along pretty good, I think. Still quite a lot left to do, though. I plan on having it done before school starts again, though.

Construction Has Begun

Finals finished yesterday, for me, so I now have about a month with a lot more free time on my hands then I’m used to having. This is a good thing, I needed a break. It also means that I can, and did, start construction on my quad, for which I received all the parts to build back in October.

Right now, I have assembled the frame, which was made out of a 6″x6″ piece of 1/4″ thick birch plywood. This is the “body” of the quad, the platform upon which everything will sit. On the bottom, I attached the four arms with wood glue. The arms are 1/2″ square basswood, each 13.5″ long.

Here, I am aligning the arms onto my workbench, and using tape to secure them so they don’t move until I can get them glued. Not shown, but I also taped the arms to each other in the center, for gluing.

I applied glue to the arms.

I applied pressure, and wiggled it back and forth slightly until it felt “attached”, then held pressure and used my PowerShot staple gun to sink in two brads per arm, to hold them in place while the glue dries. The strength comes from the glue, not the nails. The brads were flush sunk with a hammer, as the staple gun leaves them sticking up about a millimeter or two.
Yes, that board is 6″x6″, and yes, I have big hands.

That entire process went really quick. I didn’t show it, but the plywood came as a 12″x6″ sheet, and I simply used a miter saw to cut it in half for my quad. Nothing fancy there. Here is the quad as the glue dries.
Lots of cool stuff in this picture.

I have to go run some errands, but once I come back, I plan on starting some work on the quad’s electronics, so there may be another update today still. If not today, tomorrow for sure.

Finally, It Has Arrived

When I woke up yesterday afternoon, I was pleasantly surprised to see two boxes sitting on the table, as I had only been expecting one. Around the start of October, I placed a second order for my dad and myself, for a couple more props, a LiPo back, an ESC for the airplane I plan to build, some XT60 connectors and some balance charge extensions. This order arrived in New York by the forth, much faster then my initial order had taken, and within a day had been processed and shipped on, so I expected it soon. However, my quad order, which was placed a week and a half before then end of September, was still listed as being in New York. Indeed, when I checked the tracking yesterday after it had arrived it was listed as delivered, with no updates between New York and Illinois. Either the USPS has invented teleportation, or their tracking sucks, and I’ll place a large bet it’s not the former.

Although pleasantly surprised that my quad parts had arrived, there was a second reaction bearing a certain foreboding, as one of the boxes was pretty crushed in shipment.
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Somehow I just knew the crushed box was my quad parts, the box that was three times as valuable as the other one, and indeed I was right. My biggest concern was the LiPo battery, and that it might have incurred shipping damage. The USPS does not allow international shipment of any sort of lithium batteries, so if I needed to return the battery it would have to go back via EMS or UPS and would probably have cost more then the battery was worth. Luckily, it was the best packed item in the shipment. It was wrapped in foam film, for lack of a better term, the type of packaging material usually used to wrap TV’s and computer monitors. Then it was placed in a small box, wrapped tightly in bubble wrap and taped securely.
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Not only that, but checking the cell voltages showed that all cells were at 3.85V, exactly matched, and a little research also told me that 3.85V is the voltage you want your pack at for the longest storage life. I haven’t tested the pack yet but it’s off to a good start just from the voltage check.
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In what initially seemed the opposite, everything else seemed to just have been chucked into a giant bag and thrown into the box. Further inspection told me I need not have worried, as the motors were wrapped in more of the foam-film, and honestly, nothing else was very fragile anyway.
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All in all, the contents of my $180 worth of parts from the order I posted about when I started this blog seemed slightly underwhelming. I expected…well, something else, I guess. I suppose it has to do with the fact that I have a lot of time ahead of me in testing, balancing, and building before I get to play with it.
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The second order which I did not mention on the blog in detail yet contained two fire resistant fiberglass LiPo charge sacks for my dad, which are referred to from here on as Lipo sacks, and one for myself. It also contained balance lead extensions for 3s batteries, so that the batteries would be able to sit inside the lipo sacks while charging, as the attached lead is fairly short. It also contained 4 servos and one ESC for upcoming my upcoming planned airplane(s), XT60 battery connectors, and a few more spare props. Although one third of the cost of the other order, it took up about the same table space.
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At this point I unwrapped and opened everything but the small items, and arranged them next to each other. I will cover details on the individual parts as I come to them in future blog posts, must likely as I test or attach them to each other and to the quad.
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Still much to do (well, everything, really), and I still have to move. I probably won’t be able to resist playing with it somewhat tomorrow, but I will need to sleep for a good period of the day as I am currently very short on sleep, and after that I will most likely do a little more packing and cleaning for my upcoming move. I’ll update later when I have something to update with.

Updates – 9/27/12

I now have the flight control board, the Naze32. It was surprisingly small, the picture on the website was bigger then this thing really is. For a size comparison, I set it on the keyboard of my laptop.
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That was nothing compared to the FrSky telemetry link that came with it.
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I have hooked the board up to my computer and with the MultiWii GUI interface I could see the sensor outputs changing as I moved the board around, so everything seems to be working.
I’m at school right now, but over the weekend I plan to do the following, including documentation here on my blog:

  • Pick up a cheap multimeter from Harbor Freight for testing components.
  • Finish my JR6201 72Mhz to 2.4GHz FrSky conversion.
  • Cut the sheet of plywood for my quad base, and glue on 1/2 inch square, 24″ long basswood arms (yes, another design change).
  • Update the firmware on the Naze32 and learn the interface so I know what to do when I have my quad built and I’m eager to fly.

I’ve got a whole lot of research left to do, mainly stuff that applies to FPV, when I’m ready to get that set up. But I’ll tackle that when it comes to that. I believe FPV will be really, really fun.