Feedback Requested - Eggtimer Telemetry Module

[cerving]

As some of you know, in the documentation for the Quark is the mention of an Eggtimer Telemetry Module. This was a board that I did a proto for that was supposed to send altitude and possibly deployment status data to an Eggtimer LCD receiver, much like the TRS but without the GPS data.

I haven't had a chance to develop it any further, but I've been getting some feedback that users would like some kind of general telemetry I/O board that they could use to interface their own sensors and whatnots. I'm thinking of adding a few digital and analog inputs to the Telemetry Module, and making them configurable so you can control what the data looks like on the receiving end.

So, what I'm looking for is:

1) How many analog/digital inputs do you think is a good number? (The A/D inputs would probably be normalized to 1V p-p)

2) What sampling rate is acceptable?

3) How many A/D bits do you think is acceptable?

and the big one...

4) How much would you be willing to pay for the transmitter? It would work with existing Eggtimer receivers.

Thanks for your input!

Cris Erving
Eggtimer Rocketry

 

[4Ryan]

1. 2 analog and 2 digital inputs minimum. It would be great to have 2 digital outputs that could be triggered from the receiver as well. It would require a firmware update for the receiver but it'd would be useful.
2. The sample rate would depend on the type of input being monitored. I'd say whatever the max rate is that you can squeeze out of the micro.
3. 10 bit A/D should be lots.
4. Hmmm, price. Let's see, there's a pcb, micro, transceiver, ideally headers, and some bits. $50 for the kit.

 

[Charles_McG]

a 3 axis accelerometer would need three channels, yes?

You put a serial output on the Quark, so would this have a serial in? Or two?

 

[michigander]

I will buy it what ever you come up with , sounds cool

 

[KenRico]

Any thing with an accelerometer is still fairly pricey .. r@ven or m@rsa ..

Kenny

 

[Charles_McG]

But a robots sensor module, from sparkfun for instance is $20-40. Being able to tie in that kind of sensor might make for a number of interesting projects. Acceleration. Gyro. Probably light/sun and other interesting ideas.

An I2C bus might be very interesting. Cris had already floated serial, coming from the Quark barometer, for instance.

 

[cerving]

Problem with an I2C would be that you need significant processing to do anything with it, and if you get it wrong (i.e. wrong address) it tends to just hang. I can see an accelerometer, though, but since this is a standalone telemetry product it's not going to be tied into the deployment events.

 

[Charles_McG]

I wondered about network overhead.

Well, a number of those sensors are available with analog outputs. I'd say 3-4 A/D channels. Accelerometers are a frequent request into your threads, but I wasn't suggesting you put one on. But a generic DAQ could log the output of one acquired elsewhere. Maybe a 5V regulator to a header pin so that a separate power supply wasn't needed would be handy.

Thinking along the serial lines, can you jog my memory - does an eggtimer output it's flight state (waiting for launch, launch detect, min altitude exceeded, etc) to the serial port? One could use the telemetry module to radio that home.

 

[cerving]

The only thing that the Eggtimer sends out currently is altitude. Not sure if I can do much more... there's essentially no flash program memory left.

 

[djkingsley]

I would like to see a 3-axis accelerometer with 250G in the x direction 16G in the others as part of the transmitter, most of the devices from adafruit are I2C or Serial it would be nice to use the packaged sensors.

 

[Charles_McG]

You've said before that 'All Bytes Matter'