Better connector for Electronic Bricks?
It’s reliable and of 2.54mm pitch, but we always found it too big to fit on smaller modules, and the DIP pin hinders smaller bricks. The accelerate-meter looks cuter sitting on the connector, but would you prefer a smaller SMT one?
We were brainstorming use some of our electronic brick sensors as alternative probe for DSO nano, quite a part of the sensors do the job and why don’t we just use 3.5mm audio jack as the electronic cable? The cost would be much lower, since minions audio jacks are in current stock.
Though we are quite excited about this upgrade. We are still worried about possible bridging between Vcc and GND. Some in-depth endurance test of this design is needed.
PROs:
- Smaller
- Compatible with DSO nano, Music Shield (why not record something other than audio?)
- Widely available
- Much Cheaper
Cons:
- Possible shortage while plugging
- not 2.54mm pitch
- Other unknown issues
How do you think? 🙂
About Author
One big reason for using 3.5mm Audio jack is that it could be compatible with quite a lot of wired sensors, PC mic input and DSO Nano. The cables and connectors are extreme cheap with endless choices.
How about TRRS jack? http://upload.wikimedia.org/wikipedia/commons/thumb/7/7d/IPod_and_iPhone_audio_plugs.JPG/220px-IPod_and_iPhone_audio_plugs.JPG
TRRS => Signal 0, Vcc, Signal 1, GND.
Could this totally prevent shortage while live inserting? Seems working after some quick experiment here.
The worst case is still someone attempts to connect iPhone to electronic brick shields, which will apply VCC to Mic… Haven’t got a chance to try out yet, in hope it has internal DC filter.
p.s. if you do use mini-audio jacks, be aware that some idiot is going to plug in an energized jack into their $400 iPhone 4 and burn it out.
You really can’t win with TRS. If you have it:
Tip +5V
Ring GND
Sleeve Signal
The problem is that the tip is energized when you live plug it into your sensor. Theplug tip could then easily short with the signal of the jack, burning out your sensor. The advantage though, is that it is hard to burn out your MCU.
—
If you do it the other way:
Tip Signal
Ring GND
Sleeve +5V
Then you can risk burning out your MCU when you plug something into its jack, since the sleeve can get accidentally shorted against the ring.
All in all, I’m not a tremendous fan of TRS….. or RJ11/RJ45.
Why not use something like JST-XH3 connectors? They are small and readily available?
Karen
How are you doing it? Isn’t it like RJ45 where you need a special crinping tool to press it together?
RE: RJ11
Beware that some unknowing fool will do one of two things:
a) plug the device into a live telephone port
b) plug the DSO nano into a live telephone port
If either of those two things happen, it’s potentially worse than using the stereo connector (mini plug).
imho – don’t use standard jacks in places where the electronics could be damaged by an idiot.
i like the rj11 idea. they’re small, compact, cheap, ultra fast to wire up, no chance of shorting .. if you break the latches, then you can’t be very gentle ..
It sounds like a good idea, my question is though, especially for the digital or communication lines would the headphone jack create an unneeded noise on the lines?More so if it’s susceptible to vibration or movement.
What about a 3pin IDC connector, like the ones on the computer fans?
Forgot in my previous post.
A bad thing with the jack connector, is that is is higher (at least all those I got laying around are) than the current connector.
Another problem is when you disagree on what side of the print it should be. I got some bricks where I am going to move the connector to the opposite side, because it is located in a way that makes it difficult to mount. The jack connector can’t just be soldered off, and then then soldered back on on the opposite side.
Another bad thing with the RJ11, is that you need the right equipment to put it on. Jack, or the current can be put on just by using a soldering iron (mostly jack), and for the current you can do it with a wire cutter, as long as you are gentle.
The problem with RJ11 connectors is that the latch breaks very easily.
I have had very bad experience with those, they are not designed to be manipulated 5 times a day… and for prototyping I’m not sure how long it could last. :-S
[quote]Thanks for eagle eye! Would you need a couple of water sensors? [/quote]
@ESP: Oh, why not? I’m planning to automate my plants watering and it seems perfect! 🙂
Here’s an idea:
Use a telephone modular plug (sometimes called a rj11, although not strictly correct).
Pros:
– gives you 6 pins in one connector
– available everywhere
– easy to make cables (network guys often have a crimper)
– can buy ganged jacks (eg. 4 in 1)
– supports shielded cables
– ok price (not sure how it compares to your existing connector)
– rj11 plugs can be plugged into a rj45 jack, makes it
possible to design a flexible system with 8 pins and
6 pins where the 6 pin connectors fit into the 8 pin
connectors; allowing rj45 jacks to be used for multiple
functions
The 3 extra pins in each connector could be used for
stuff like unregulated power.
Anyways… something to think about. I have some
ideas on how to standardize the pin layout for this.
I can post a follow-up if interested.
John
Thanks for eagle eye! Would you need a couple of water sensors? 🙂
But wait…on the last photo:
wwwW.seeedstudio.com ?
Hello,
I use TRS jack, but please avoid shortages by using:
T>GND
R>Signal
S>+5V
Switched contacts can be usefull in many cases for avoid shortages or floating values when nothing is connected.
Would reversing the VCC and signal pins help? Seems like the short is only possible because they’re next to each other.
#Jens
It would be 100% safe when turned off while plugging, but accidentally pulled off might cause shortage too. Maybe a fuse will provide a rough protection, and AVR is strong enough on its legs…
Hi!
I’m not sure – just today customer complained that he has bricked 🙂 RTC module after he had polarized it wrong way, so maybe it is not good idea?
That’s a great idea!
I have actually ordered a dozen minijack connectors to do the exact same thing! 😀
Regarding the shortage risc, would the most prune thing not be, to have the devices turned off? 😉