Low Cost Proximity Sensor Suggestions for Servo Controller Card
GeorgeCollins
Posts: 132
I have a general sensor question. I have been building a robot kit with the Parallax Servo Controller. You can see it here: http://youtu.be/gAr3EOZMq6Y . The PSC is great because it is inexpensive, small, and has servo headers. The kit works with a Gadget Gangster board as well, but if you use that then you have to spend more and solder, which isnt so good for a kit. So I prefer to use the PSC.
On the PSC, all of the exposed pins are connected through a TXB01008PW chip, even the serial in is on a similar circuit. The robot controller card had a similar setup, but you could put in a jumper to bypass that chip and that is how I would connect some sensors. It turns out you can connect a Parallax Ping sensor to one of those headers or to the Serial Input header and it will work. The problem is that a Ping sensor needs a very particular voltage level and its kind of expensive so that it would be impractical to use more than one. This robot works fine with just 4AA batteries, which makes the whole thing really cheap, but a Ping sensor needs more power than that.
I would like to find an IR sensor that will work through that connection. I just tried a prox1 from Rays logic (which is a great sensor and seems to work fine at 3.3v and 5v: http://www.rayslogic.com/Propeller/Products/Merlin/Prox1.htm) and it does not seem to work. Does anyone have a suggestion of an IR sensor that I could connect through those header pins?
What about other touch or proximity sensors?
On the PSC, all of the exposed pins are connected through a TXB01008PW chip, even the serial in is on a similar circuit. The robot controller card had a similar setup, but you could put in a jumper to bypass that chip and that is how I would connect some sensors. It turns out you can connect a Parallax Ping sensor to one of those headers or to the Serial Input header and it will work. The problem is that a Ping sensor needs a very particular voltage level and its kind of expensive so that it would be impractical to use more than one. This robot works fine with just 4AA batteries, which makes the whole thing really cheap, but a Ping sensor needs more power than that.
I would like to find an IR sensor that will work through that connection. I just tried a prox1 from Rays logic (which is a great sensor and seems to work fine at 3.3v and 5v: http://www.rayslogic.com/Propeller/Products/Merlin/Prox1.htm) and it does not seem to work. Does anyone have a suggestion of an IR sensor that I could connect through those header pins?
What about other touch or proximity sensors?
Comments
Tell me if you want more information and I will russle some more up. I presume you would know where you would get IR sensors and emitters, if not, I can't help you as I presume you live in the US and I live in Aust and I don't know what shops they have o'er there.
I personally don't see the appeal of the Servo Controller. A QuickStart can also control a bunch of servos and costs less. I made a little demo to showing a QuickStart controlling 32 servos.
I also don't like logic level converts. The one on the S2 keeps it from interfacing with the Ping and a bunch of other devices. I've found very few 5V devices that wont work with 3.3V logic. In those rare cases when a device wont work with 3.3V logic a transistor can take care of the level shifting.
A 3.3K Ohm resistor is enough to protect a Propeller chip from 5V signals.
For wireless communication, I'm a fan of Nordic nRF24L01+ modules. This isn't a sensor, but it is low cost. SparkFun sells several versions and there are modules sold for less than $3 on eBay. They require six I/O pins, but if you use a QS instead of a SCC you'll have ten extra pins to use.
I've purchased one of the cheap PIR sensors off eBay but I haven't tried it out yet.
Edit: I just watch the YouTube video. Very cool quadraped! I like it.
For IR, I am not looking for a transmitter and receiver. I can solder together circuits for myself. But for someone like my son I need something simple, preferably with little or no soldering required. That quad you see in the video requires no tools to assemble except a screwdriver and its about $150 without the ping sensor and the battery. If I didn't have to use a ping sensor I wouldn't need as good of a battery. So if I can find a simple sensor I can make the whole thing really cheap.
Thank you for the ideas though.