Wednesday, January 29, 2014

FrSky Products: Which to Get?

FrSky products are great, but the names make it easy to jumble them together.  Here's a breakdown of the three main families of products.

Simple Purchase Advice:

  • Buy a Taranis if you need a radio and if you can find one.
  • Buy an XJT module if you've got a 9x, 9xr, or other JR-module compatible radio
  • X8R if you want S.Port compatible telemetry or SBUS servos.
  • D4R-II if your need a small Rx that supports CPPM.  Perfect for multirotors.

X Series
  • module: XJT (JR)
  • Smart Port, Telemetry
  • receivers: X8R, X6R
  • Taranis has XJT internally
  • uses "smart port" sensors

D Series

  • modules:  DFT (Futaba), DJT (JR)
  • telemetry
  • receivers: D8R-XP, D8R-II Plus, D4R-II
  • uses "hub based" sensors

V8 Series
  • oldest series
  • no telemetry
  • receivers: V8R7SP, VD5M, V8R4-II, V8R7-II, V8FR-II
file: {"toc":["FrSky"]}

CP210x Drivers for Flip Boards

So it turns out that the Flip boards use a SiLabs CP2102 for its serial/USB interface, and I didn't have the drivers on either my Mac (quelle horreur!) or Windows boxes.  The symptom is that you bring up the Arduino IDE or the MultiWii GUI and don't see the device in the list.

Thankfully, Pololu has drivers (and instructions, if you need them) for both of these and Linux as well.  The page mentions MacOS 1.7 but it seems to work fine on my MacOS 1.8 box as well.

On the Mac it installs as /dev/tty.SLAB_USBtoUART.

Monday, January 27, 2014

Noodle Copter Update

If you're coming here for NoodleCopter information, Welcome!  Here's most of the NoodleCopter things pulled together for your convenience:

NoodleCopter Posts

Sunday, January 26, 2014

Making a Continuous Rotation Servo

NOTE!  There are a couple of different designs of these servos, even from the same vendor.
  • The written notes below are for a through-hole style board
  • The video covers the non-through-hole syle
  • One kind of Potentiometer has rotation stoppers which must be broken off.
  • One kind of Potentiometer rotates freely and doesn't need to be modified.
  • If you don't need to modify the pot, you don't have to remove the stack of gears.

Continuous rotation servers are popular for cheap robotics projects because a pair of them give you a complete drive train (motor, controller, and gears).  A pair of 9 gram servos (such as the popular HXT900 from hobbyking) should be less than $7 or so.

Start by testing your servo, either with a servo tester or with an arduino sketch that drives the servo back and forth.  There's nothing more discouraging than having bad results, only to find out that it's not your fault because you started with a bad unit!  Likewise, be sure and test your battery voltage.

Tuesday, January 21, 2014

Using the Spektrum DM9 module with Taranis and Turnigy 9xr

Daedelus66 notes that these settings work when using a DM9 in a Taranis (and presumably other {er,open}{9x,tx} radios):

  • polarity set to +, rather than the default - (which works with the Orange module).
  • preferable but not required to set PPM to 400u instead of the default 300u. ensures neutral remains at 1.5ms -- if left on 300u it will be significantly shifted and require recentering servos.
  • DM9 uses only the three basic pins: signal #1, positive #3, and ground #4. Pins 2 and 5 are unused, so no problem there.
  • model match not supported.
  • rebind by holding the module button while powering up.

Monday, January 20, 2014

Sunday, January 19, 2014

Taranis Module Pin-Out

Courtesy of RCG user smoothvirus, here's two shots showing the pinout for JR-style modules.  The first is an actual JR radio, the second is the motherboard on the Taranis.

This should be the same for 9x and 9xr as well.

It was suggested that it would be useful to measure the voltage under load from the module connectors when calibrating the voltage.

Thursday, January 16, 2014

Concord Model Engineers Minutes, January 14, 2014

Concord Model Engineers Monthly Meeting
Tuesday, January 14, 2015

CALL TO ORDER: 7:30 pm

A Tale of Two Robots

Getting ready to put together another electronics class.  This one will be themed around robots, so I'm looking for likely candidates.

Here's Popular Mechanic's Build Your First Robot project. Points to more details here.  They're estimating about $100, but I think it can be pulled off for less.

And via Hackaday, the Red Rover.  It's tiny, 3D-printed, and uses rubber bracelets for treads.  May be a pretty cheap way to go!

I've got parts coming in for both, so I'll make a page for each of these and put collected information there.