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        Discussion FrSky 2.4Ghz - Telemetry Hub & Sensor discussion

#1 PLMS Jul 14, 2011 08:04 AM

FrSky 2.4Ghz - Telemetry Hub & Sensor discussion
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Time to post up some first looks at the new DHT-U LCD screen and the matching telemetry hub and it's sensors. I have a set of gear to check out and test.

#2 PLMS Jul 14, 2011 08:16 AM

The hub
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The telemetry sensor hub (the bit that reads the sensors and sends the information to the RX for transmission down to the TX handset).

My first thought when I popped it out of the bag was 'gee it's smaller than I expected'. It's both thinner and lower footprint than expected really. It uses narrower pitch header connectors than servos etc, somewhere around 1.2mm pitch.

#3 PLMS Jul 14, 2011 08:24 AM

Vario FVAS-01 first look
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The vario (sensor for height change).
I'm not sure yet but I think it's got a Bosch BMP085 sensor in it. I'll open it next week and see. I've seen that sensor before somewhere ;)
Again it's small, size of a postage stamp and only a few mm thick.

#4 PLMS Jul 14, 2011 08:36 AM

Fuel Level Sensor first look FGS-01
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OK, this thing will be interesting to test, as I have but one glow model now (all else is electric)...
I'm not a sensor expert by any means, but I think it's a capacitive device, meaning it might sense the effect of fuel next to the foil plates when it's on the side of the tank. It would measure the capacitive change between them (a small guess again, please tell us here if you know more than I do).
They would need a lot of input filtering in software to get a stable result, as the fuel would not stay still in the tank.
We'll see soon how good it can work. I have a spare tank I can do a simulation with.

#5 PLMS Jul 14, 2011 08:47 AM

Temperature sensor TEMS-01
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This looks like a standard glass bead thermistor. Not much to say at first look other than it's got nice teflon wire, and it's near 30cm from plug to sensor.
It's very similar to the ones used on my Eagle Tree E-logger, but I think it's a different value (not compatible).

#6 PLMS Jul 14, 2011 08:56 AM

GPS and the three axis Accelerometer (GPS-01 & TAS-01)
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The system has a GPS sensor, and also a three way accelerometer sensor.
The GPS is an easy way to get ballpark values for position, height and speed. I guess the accelerometer will measure G-force when turning tight or climbing.

#7 PLMS Jul 14, 2011 09:03 AM

RPM (revolution speed) sensor RPMS-01
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Again it's quite small, for an optical device anyway.
On my Eagle Tree logger I found the RPM sensor to be quite useful, and I suspect this sensor will be useful on the FrSky hub system.
One thing occurred to me right away is monitoring head speed in flight with my helicopter. I'll try pointing it up through the main rotor arc or through the main gear. Normally it's used to measure propeller RPM on a plane.

#8 PLMS Jul 14, 2011 09:08 AM

More to come
I know the above first looks are very light on measured results and data, but as I have some commitments till next week that have to be done first.

In the meantime, if there are specific questions about the devices that need to be asked (and answered) then let me know and I'll try. Specific though, not like 'how good is it'. That sort of answer will take weeks to know about.

I'll get back on the thread next week and see whats come to mind.


#9 A10FLYR Jul 14, 2011 09:18 AM

WOW! Unless you have big hands the airborne bits are smaller than I was expecting and the dashboard is a proper size. Good on FRSky.

Now to see what the price will be....

#10 lothar2048 Jul 14, 2011 11:46 AM

I still have a problem with FRSKY.

Some of us are using an OSD and googles to fly in FPV mode. Those informations can be usefull if they could be taken on a ground station, or catched to be chained on an I2C bus and sent to an OSD chain.

I've been trying unsuccessfully to ask them an analog RSSI port on their Telemetry receiver. Till up now, they don't took care of this wish.

This would have been great for people with googles as looking to a screen is difficult when you wear such things ;-)

Otherwise, it looks very promising. I hope this hub could also be used in conjunction with a future OSD the would make. Hope they do, and add also a stabilisation system, and they would have the first have it all flying solution...

I also hope they would proving a software for a ground station that would work with an RS232 interface like an FTDI cable.

I hope too that the data port is outgoing the data. If this is the case, it should be used for an OSD project.

There a too type of fuel gauge. Immersed and not immersed. But i can't tell you if this one is using capacitive or resistive technology. It depends of some factors that are not veiwable as is.

Would be really great as usual. I love their TX and RX even if i can't use the RSSI on an OSD directly. I had to make some soldering and build a buffer for that.

#11 renatoa Jul 14, 2011 12:34 PM

The new D4FR receiver outputs RSSI.

#12 Daemon Jul 14, 2011 03:08 PM

I'm not quite seeing what the antenna is for.
Does the telemetry module replace the Tx module?


#13 renatoa Jul 14, 2011 03:28 PM

Yes, the choice of the name DHT-U was to suggest it is an Universal DHT.
The wires seen in the picture are not serial line to fed from Tx module, but power and PPM from Tx.

#14 GBR2 Jul 14, 2011 05:48 PM

Aren't they going to have a display that can just plug into the Tx module and provide the same information? Similar to the Graupner Hot Box. Or isn't that possible with the current Tx module design? That was what I was looking for.

#15 Chase Wu Jul 14, 2011 11:40 PM


Originally Posted by GBR2 (Post 18763329)
Aren't they going to have a display that can just plug into the Tx module and provide the same information? Similar to the Graupner Hot Box. Or isn't that possible with the current Tx module design? That was what I was looking for.

Current FrSky LCD-fdd_lite can be plugged into the Tx module by a provided cable, show two analog voltages, Rx RSSI, Tx RSSI and is capable of programming alarm thresholds and directions on-screen: http://www.frsky-rc.com/ShowProducts.asp?id=91

We have been putting hands on another display, besides current functions of LCD-fdd_lite, it can show all monitored data. This new product is presumed to be ready within two months, let's look forward to that!

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