## Which option best describes your opinion?

• ### I prefer USB built-in, even if it adds slightly more cost than IRDA.

• ### I prefer a serial port connector, and $30 optional USB adapter to change settings if needed. Results are only viewable after voting. #### FROB ##### Well-Known Member Hi Folks, Well i'm zeroing in on a design for- well lets call it something very special and cool- in terms of low cost but full featured rocket-tronics. The dilemma i have is this: I'm trying to keep the cost down as much as humanly possible, while still supporting an optional PC (or PDA) interface. It turns out that IRDA - though its popularity is waning at the moment - could be the answer. An IRDA xceiver only adds about$2 to the cost of the circuit.-
But then you dont need to buy anything else to make it work, assuming you have a pda or laptop with an IRDA port. Or you can get a cheap $10 USB dongle to do it. Personally i like the idea of being able to aim the IRDA dongle through a clear window on the rocket to get data and adjust the config without having to take the ebay apart or physically connect any cables. This also help reduce the risk of ESD damage or accidentally triggering the deployment charges. The other benefit is that by not having dip switches or other user-interface on the board, it can be made small enough to fit inside a BT-3 or BT-4 tube. Given the choice, in a low cost "altimeter"/timer/whatever that you'd pay anywhere from$40 to $100 for, would you prefer: 1- IRDA as a built-in function, necessary for all configuration and data download 2- Same low cost, no IRDA, with the option to get a$30 add-on USB serial interface/cable to change the default config or access flight history.
3- Pay $15 more for the basic altimeter, but have USB built-in right on the board 4- Pay$15 more and have a bunch of buttons, dip switches, led's etc. on board so i never need a PC interface, making the board bigger too.

EDIT: the poll has 2 parts, and i've allowed multiple selections to allow you to answer both simultaneously :
Part 1 is about IRDA in general (first 3 questions)
Part 2 is about your preferred interface- IRDA vs serial port vs USB vs dip switches and buttons/LED's for user interface - you can have only one of these choices, not all 4!

Last edited:

#### dlb

##### Sky Pyrate...
don't know the cost on adding Bluetooth, maybe that's another avenue to think about, my computer and cell phone/mp3 talk alot.

I do have IRDA on my older Ipaq, but somehow it got stuck running software for my telescope.

one thing I always wanted to see was , like 4 outputs, 1 for apogee, 1 for main (user programmed) and 2 for things like airstarts or lights or sound or whatever control ( user programmed )

#### FROB

##### Well-Known Member
don't know the cost on adding Bluetooth....
Thats an interesting idea - it did cross my mind: I'd consider it as an add-on for a high-end unit, but for a very-low cost one, I'm afraid it's too costly and takes up too much space on the board. it also requires an upgrade to fineline/multilayer boards which also increase the cost. It wouldn't be too hard to do though, i have used Bluetooth in a couple of designs before.
Currently the cost of adding Wilan is not much more than Bluetooth, so i'd probably consider that first for a high-end unit add-on.

#### standardrockets

##### Active Member
In my experience IRDA has very limited range if either end is bathed in sunlight.

#### FROB

##### Well-Known Member
In my experience IRDA has very limited range if either end is bathed in sunlight.
True, but i don't see ever needing more than a few inches of range- do you? Even with the clunkiest laptop it shouldn't be to hard to hold its irda port within a couple inches of of the rocket, with the device just inside a small window or opening.

#### FROB

##### Well-Known Member
Well, looks like the people have spoken - IRDA is out, USB is in.