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Author Topic: DIY timer kit for F1S / E36?  (Read 2214 times)
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Liav
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« on: April 27, 2017, 03:21:50 AM »

Hello everyone,

Maybe you saw my post here regarding my new Timer for F1S / E36.
I found out recently that many E36 timers are coming in a much larger size than my timer, and uses bigger through hole parts, instead of tiny SMD parts like in my Tiny Timer.

Well, if you are not concerned about bigger and heavier timer than the Tiny Timer, why not making a bigger timer?
Or even better, why not making it as a kit that can be soldered easily by anyone?
I can design a new PCB for through holes "Normal" size parts.
This can be also a nice challenge for kids who build their own E36 / F1S by themselves.
The timer will be the same as the original except for the size and weight, and the kit will be much cheaper than the original tiny timer F1S / E36.

Please let me know if you are interested with this kit, and if we get a significant amount of orders, I will start designing the PCB and order the new parts.

Thanks for reading all,
Liav

https://scontent-fra3-1.xx.fbcdn.net/v/t31.0-8/18076580_10155365835592682_5287029205156322827_o.jpg?oh=9410d689e3a9cd0124cb4b8e5d7c9382&oe=5979CABB

https://scontent-fra3-1.xx.fbcdn.net/v/t31.0-8/18121114_10155365836592682_337013718963448767_o.jpg?oh=dd7253c5a976667916596136bf315dfd&oe=59882E41
DIY timer kit for F1S / E36?
DIY timer kit for F1S / E36?
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msc
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« Reply #1 on: April 27, 2017, 09:56:05 PM »

For a kit version I would suggest somewhere in between. Going with larger surface mount packages you can get into the skill range of most electronic hobbyists. SO8 and 0805 size packages are reasonable to work with. 1206 would be even easier. Provide the fine solder with the kit and recommend the use of a flux pen should make it successful for most people. It could be a great kit for hobbyists to get experience with surface mount.

By the time you put in the effort to prepare kits and the extra instructions I think you will find it difficult to offer a kit for much less the the cost of an assembled unit. The customer service aspects of answering email, processing payments, and shipping units require as much or more effort then assembling.

I expect the majority of kit sales would be to people that would enjoy the assembly rather then to people trying to save a couple bucks.

What is the process for adjusting the settings? Are the settings remembered when the battery is disconnected or do have to program it each time a battery is connected?

Mike
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Liav
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« Reply #2 on: April 28, 2017, 06:19:41 AM »

Hi Mike,
Thanks for your reply.

If enough people want this kit, I'll do my best to design the PCB as compact a possible, although the parts aren't small.
I'll try to see if it's better to use some SMD parts like you mentioned, but my guess is that it will be much more difficult soldering for beginners.

You're right about the effort time it's needed for all rest, but I hope my video instructions are good enough like I did with my other products.


Programming is made using a single button. All settings are saved in the eeprom, so unplugging the battery won't erase your settings.
You can see my sale post with the full PDF manual, and videos here:
http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=21979.0

Liav
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Tapio Linkosalo
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« Reply #3 on: April 28, 2017, 09:30:40 AM »

I'd like to second MIke's comment. The larger SMD components are not that hard to solder, I'd say that using through-the-hole components is much more tedious, and said SOIC case IC's, if they are like 8-legged or so, can be even soldered with a rather large iron, if using paste.

So one suggestion to consider: make the kit with SMD components, but instead of making it as compact as possible, use larger footprint so the there is sufficient room around the components to work. Also for resistors and LEDs etc, use the 1206 case, so they are easy to handle. Or maybe a combination - IC with through-the-hole case, but the other components SMD?
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msc
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« Reply #4 on: April 28, 2017, 02:12:14 PM »

I'm not your market for this timer so my comments are intended as helpful suggestions. Of course you should design for what you see as your market.

As an example of a basic surface mount kit that proved workable for hobbyists take a look at this site http://rfid.marcboon.com/. This is a kit for a simple credit card size RFID detector that the designer ran several workshops on how to assemble. With little instruction they had people with no soldering experience working with 0805 size components.

I have not been able to view the pdf instructions for your timer. I use an older computer and it's having trouble with your pdf file. Saving your file in an older more compatible pdf format would solve the issue. I did watch the video so I have a good overview of the features. I would like to see the text instructions to better understand the finer details of the menu operation.

I do see potential for adapting your design to an E20 timer and that is something I am in the market for. BSD offers a nice little E20 timer but I would like to see one with more flexibility in the programing options. I have some thoughts on how to package the entire timer, ESC, and DT actuator on a single board designed for flush mount installation and weighing about 1.5 grams.

Mike
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Liav
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« Reply #5 on: April 29, 2017, 12:24:33 PM »

First, thank you for yout comments.
I really appreciate that, and you can continue suggest everything you have on your mind  Cheesy

I understand you prefer SMD parts where's possible, with big footprint like 0805.
In my opinion, holding the part in place during soldering is the tricky part, especially for beginners.
With TH parts, you can bend the pins and then solder while it stays in place.

Maybe I can design 2 PCBs, one with TH only, and the other one combined as you suggested.
And Tapio, you're right about the room for work. I thought about it too.

Mike, the PDF file is a standard PDF format. Probably dropbox making it difficult to run?
I can send it to your email if you want.

E20 is new to me. I didn't know about it.
I read the specification of the BSD timer, and as I understand, the timer should drive the prop motor, which is a DC motor? and also the actuator for DT.
Am I right?


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Liav
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« Reply #6 on: April 29, 2017, 12:43:01 PM »

Mike, about your PCB design for E20, if you only need a pre programmed IC, then, I can modify the software accordingly.
I write the code and burn the ICs myself.
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msc
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« Reply #7 on: April 30, 2017, 04:23:28 PM »

Your code would run an E20 timer with very little modification. Simply changing the output routines is all that is required. Some servo and ESC setup menu items can be removed but that would be optional.

The motor driver would be a simple high bit for 100% and PWM for lower power settings.  An NFET with a couple protection components is all that is needed for the motor driver.

I have seen requests for prop braking. I assume the simple approach would be to use a PFET to shunt the motor. It would be a nice feature to add if there is a bit available to control it. Perhaps omit the RDT input if that's a bidirectional port.

The DT actuator can be either a band burner or spin off type. Either one would simply have an NFET to turn power on for from 0.1 to 1.0 seconds. This thread has good discussion of low weight DT actuation. http://www.hippocketaeronautics.com/hpa_forum/index.php?&topic=14779.0

I think the spin off type will be the better choice. I have some tiny pager motors on order to test if they have the torque to do the job.

Here is a thread with discussion of the E20 class. http://www.hippocketaeronautics.com/hpa_forum/index.php?&topic=14519.0  Basically 20 inch span limit, an 8.5mm brush DC motor (PKZ3616) and a DD prop limit of 2.6 inch. I think it started as a club event and has gained a fair amount of popularity. It has been flown as a provisional event at the U.S. Nats.

For the form factor I have a target of about 0.6" x 0.8". The outer surface gets the switch, LEDs, and a short threaded stud for the spin off DT actuator. All other components will be on the back side of the board. This will give a very clean installation when mounted flush in a surface.

I'm starting to work on a half size version of the 1/2A Starduster and want to keep the timer, battery, and wiring inside of or flush with the body. I would like a timer ideal for this project and expect others would like this form factor too.

I'm pretty good with hardware design/packaging but only a hack with vintage basic when it comes to software. I would have a steep learning curve to pick up a C development environment.

I'll proceed with developing the drive components and DT actuator. I'll need some details about the MCU pin outs and I may as well use the same LEDs that you have been using.

If others are interested in the E20 timer it would be fine with me if you were to produce/kit and sell them. If I were to take on trying to produce and sell them you would get some profit built into the price you sell the programmed MCU for.

Mike
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Tapio Linkosalo
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« Reply #8 on: May 01, 2017, 07:19:33 AM »

The motor driver would be a simple high bit for 100% and PWM for lower power settings.  An NFET with a couple protection components is all that is needed for the motor driver.

I have seen requests for prop braking. I assume the simple approach would be to use a PFET to shunt the motor. It would be a nice feature to add if there is a bit available to control it. Perhaps omit the RDT input if that's a bidirectional port.

You think it would not work to run the motor with a N-fet and the brake with a P-fet from the same output pin?
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Liav
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« Reply #9 on: May 01, 2017, 08:06:20 AM »

I managed to design a PCB with dimensions of 20x26 mm (0.78x1.02")  Grin
This design contains TH components only.
Is it too big?  Huh
All the components should be soldered on top, except the pin headers that should be at the bottom.

Mike, about the E20 timer, I can make the software modifications.
I'm currently busy with other projects, so if you already designed the PCB and the hardware, it's fine with me to make the software only.

The Attiny85 has 8 pins:
3 pins are for VCC, GND and Reset. (cannot be changed)
And 5 pins are I/O pins:
2 pins are for driving the leds.
2 pins are for the PWM signal for the ESC and the Servo.
And the last pin is an input pin from the button/RDT

All the pins are already in use, but we can use them for more than one purpose if possible.

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msc
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« Reply #10 on: May 02, 2017, 08:26:41 AM »

I think 20x26mm is a reasonable size for the kit E36 timer. Be sure to post a picture when you have one completed.

I have no urgency in developing the E20 version. I also have many projects that compete for my time. I'm happy to have a path that can lead to my ideal timer. I'm expecting it to be a 2 to 6 month spare time project.

You think it would not work to run the motor with a N-fet and the brake with a P-fet from the same output pin?
When I was thinking in terms of the motor being either on or off driving both FETs from a single port is what I had in mind.

When PWM is added the brake turning on as soon as power is removed could be a problem. An RC time delay for the P-FET might tame that so it's still possible. If there were another bit to drive the brake separately it saves a couple components and it's easy to let the motor coast down before applying the brake. This should put a tiny bit more power to the air and reduce the peek load on the P-FET.

I'm sure there is something not too complicated that can be done. An AND gate to trigger the brake when both LEDs are on, or something like that. Looking at the ATtiny data sheet it looks like it's possible to disable the reset and use that pin as an I/O pin. I don't know if there is some aspect of the development system that requires the reset line.

Before I put too much effort into implementing a brake I need to confirm it's actually an improvement. I'm still looking for a definitive answer to, is the drag lower when free wheeling or stopped. Many things point to stopped is better but I think it may depend on the size of the prop and drag of the motor. I do observe that for P30 the goal seems to be to allow free wheeling.

Mike
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Liav
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« Reply #11 on: May 02, 2017, 11:57:24 AM »

Mike, apparently you're right about the reset pin.
I didn't check it yet, but it's good to know this pin is usable.  Grin

I know for sure that breaking the prop is better in terms of drag in P30.
I assume it also applies to E20.
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Liav
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« Reply #12 on: May 12, 2017, 10:42:22 AM »

Here you can have a look on my PCB design.
If you have any comments, please let me know.

Thanks!
Attached files Thumbnail(s):
Re: DIY timer kit for F1S / E36?
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martynk
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« Reply #13 on: June 12, 2017, 11:05:09 AM »

That looks very interesting.

How do you program it? Both the Atmel - will it support in situ programming? and how do you adjust the motor run and DT times? Could the DT servo be programmed to run incremental steps to release arms for VIT/AR then DT?
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Liav
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« Reply #14 on: June 12, 2017, 11:11:43 AM »

All the programming is done by a single button.
What is situ programming?

You can see my tutorial videos in my Youtube channel and read the full PDF manual:
Part 1: https://www.youtube.com/watch?v=k6y9U5a0OGo
Part 2: https://www.youtube.com/watch?v=aZkmyN2rP-s

PDF manual:
https://www.dropbox.com/s/39tc7h4beo71qyj/Tiny%20Timer%20F1S%20-%20E36%20V1.0.pdf?dl=0

The DT function currently is only a 90 degrees movement of the servo. You can choose the rotation direction (CW or CCW).

Liav
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martynk
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« Reply #15 on: June 13, 2017, 10:16:58 AM »

That's brilliant.  Thanks

Are these available commercially?

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Liav
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« Reply #16 on: June 13, 2017, 10:29:50 AM »

Yes,
please read my selling post here:
http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=21979.0
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Liav
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« Reply #17 on: August 09, 2017, 02:13:21 AM »

Look what Iv'e got  Cheesy

This is my first try soldering the "big" F1S/E36 timer.
I intentionally used a standard size soldering iron to understand what skill level is needed.
Actually, it was fun and easy, except the 6 pin connector, which I had to add some flux in order to let the solder "stick" properly.
I think that beginners with a some guidance can solder it.

Here some pictures of the "big" timer, and also of the tiny timer for reference..
Attached files Thumbnail(s):
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
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Liav
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« Reply #18 on: August 09, 2017, 02:15:14 AM »

And some more photos

Attached files Thumbnail(s):
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
Re: DIY timer kit for F1S / E36?
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BG
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« Reply #19 on: August 10, 2017, 01:54:53 PM »

Hi Liav,
I did not realize you were doing this. Do you think my 11 year old some could handle this?
Bernard
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F1B guy but its not my fault, Tony made me do it.
Liav
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« Reply #20 on: August 11, 2017, 03:40:11 AM »

Hi Bernard,
I think an 11 years old kid can handle it.
Of course it's important to have a minimal experience of clean and shiny soldering.
If he never soldered anything, first let him practice soldering some resistors to a pcb until he gets the idea.

The sensitive part is the microcontroller.
It's quite easy to solder, but you need to solder each pin quickly to not over heat and damage it.

And as I mentioned before,  the 6 pin connector is tricky.
If he is not skilled enough, it will be better to get help there.

All the rest of the parts are really easy to solder.
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