Sunday, May 24, 2020

Kilrah's Excellent Banggood Post

 Really BG is basic. They've got a product on the site, you place an order, you'll eventually get it when they have some, end of story.  
If you expect any kind of handholding, estimate or "reassuring" from your dealer or believe the "customer is king" mentality you don't go there, period.
RC Groups - View Single Post - RadioMaster - TX16S 16Ch 2.4ghz Multi-Protocol OpenTX Radio System

Primitive DIY Tx

Attach to an Arduino:

  •  two gimbals (4 pots)
  • two switches
  • external Tx module
Write control loop
  • read values from pots and switches
  • send PPM signal to module
  • done!

Arduino based SmartPort voltage meter

LiPo Voltage metering with Arduino

DIY lipo voltage checker (arduino) - YouTube
1S-6S Battery Voltage Monitor (ROS) : 7 Steps (with Pictures) - Instructables

Building & Testing the Circuit

Programming the Arduino

Arduino SmartPort

marhar/arduino-frskysp: FrSky SmartPort protocol library for Arduino
arduino-frskysp/FrskySP_sensor_demo.ino at master · marhar/arduino-frskysp
FrskySP: Main Page
FrSky S-Port telemetry library - easy to use and configurable - RC Groups
Google Code Archive - Long-term storage for Google Code Project Hosting.

This seems the best one:
Dakkaron/MinimalSPORTVoltmeter: Arduino Voltmeter compatible to FrSky SPort Telemetry with minimal additional hardware

Install Notes for Dakkaron FrSkySportTelemetry

#install FrSkySportTelemetry
cd arduino lib directory

# install Dakkaron
cd github place
git clone

Details on Maximum Current

Mike Blandford responds to my query:
I'd use 5V as the maximum for the SPort signal, assuming you are using standard FrSky hardware. The SPort input is via a transistor buffer with a 1K resistor in series with the base.
The SPort output is driven by a SN74LVC1G126 powered from 3.3V. When not driving the SPort signal, this has an absolute maximum voltage rating of 6.5V. 
When driving the bus, the voltage rating is (VCC+0.5) so 3.8V. 
However, the output signal passes through a 51 ohm resistor, so as long as the current is limited to 50mA the device is safe. 50mA through 51 ohms is 2.55V, so the limit is 3.8+2.55 = 6.35V. 
All values taken from the TI datasheet for the SN74LVC1G126.
RC Groups - View Single Post - FRSKY Taranis "How to" Thread

Battery Charger protection circuit

- Designed for 18650 batteries
- Up to 1,000 mA charging current
- Based on TP4056 Chipset
- Battery protection circuit
- Charging status LED's

- Input voltage : 4.35 - 6 V, 5 V recommended
- Charge cut-off voltage: 4.2 V + / - 1%
- Maximum charging current output: 1000 ma
- The battery overcharge protection voltage: 4.28 V
- Battery overcharge lifting voltage: 4.00 V
- Battery discharge protection voltage: 3.0 V
- Battery discharge termination voltage: 3.2 V
- Battery: over-current protection current 3 a
- Board size: about 2.5 * 1.65 CM
- Status LED
- Standby : Dimly lit, Charging : Red and Charge Complete : Green

Wednesday, May 20, 2020

My Moderation Philosopy

Here's a note I wrote for the Moderators' group at DIY drones. The nice words are at the beginning are by Chris Anderson who founded the site.

Our Culture and Values:
Mark Harrison, one of our star moderators, articulated our culture and policies best with this post, which I'll just quote verbatim:

Here's my general feeling about a lot of things on this site; in fact, it's pretty much my general philosophy for large parts of my life:

"It's more important to enable good things than prevent bad things"
For diydrones, this generally means:

-- Be generous in accepting blog posts. We're not at a point where there are more submissions than can be confortably digested in a day. Likewise, the term "drone" is evolving at such a fast rate it's hard to pin down exactly what it means for everyone. So, I'm happy to lump in quadcopters, FPV, gimbals, RC, artistic aerial videos, electronics, radios... all kinds of stuff that meets my nebulous criterion of "generally interesting to the diy drone community."

Now of course it can be protested, "what if we're flooded by dozens or hundreds of posts on marginally related topic X?" And my response would be, "let's wait until that happens; we'll have tons more context and it will be easier to make a specific decision then than make some globally encompassing set of rules now. We may all even be a little bit smarter and a little bit wiser!"

-- Be generous in approving users. Lots of people aren't comfortable with revealing too much information about themselves, or may not have a particularly cogent reason for joining a site. I'm somewhat of an exception to this case... "Are you asking what I'm interested in? Let's talk about me, it's one of the most interesting topics we can discuss, don't you agree?" But for a lot of people, they may interested in the topic, but not interested in telling you why.

-- Feel free to make mistakes, and be nice when other people are making mistakes. Sometimes the most interesting things happen when things go awry. For better or worse, sometimes the most education things as well!

I think this is pretty much in agreement with how the site has been run historically. It's a site for amateurs, by amateurs (keeping in mind the defintion of "amateur"... from the French "lover of"), and as such has had a pretty wide-ranging scope of what's acceptable. That's served the site well, enabling it to be as relevant (or even more!) in 2013 as it was when it was founded.

Of course there are big exceptions to this "don't sweat the bad stuff" philosophy -- brain surgery, rocket launches, and skydiving come to mind -- but I think it's a useful guideline for a site such as ours.

Saturday, May 16, 2020

Part Tester

Lcr-t4 12864 lcd graphical transistor tester resistance capacitance esr scr meter Sale -
Case for LCR-T4 (12864LCD ESR SCR Meter Transistor Tester) by HarryCayne - Thingiverse

FrSky Wireless USB Connection

e.g. for flight simulators


Arduino-based SmartPort monitors

I've got some extra Arduino Minis sitting around.  Can I make them into SmartPort sensors?

Random docs: