I'm also confirming that it works reliably with a 2.2k pullup. At 1k it stops working. The most reasonable way would probably be to hook up a meter and see if you get a good threshold. By the way, anyone knows what a good threshold (switching level) is for MSR1? Theoretical is 1.75-2V, right? My multimeter is the cheapo slow autorange kind and I can't get a good reading....
I was also able to interface Sharp GP2D15 IR rangers. These are the digital type, instead of an analog value (like GP2D12), they just flip to a logical 1 (TTL levels, 5V) when an object is within a certain range (~9 inches). I know, I know, everyone swears by the analog one, but I needed these for bumper type object detection and nothing beats just checking a pin for 0 or 1, no need for comparators, DACs, extra cogs, subsumption, etc... just a plain old if/then.
Anyway, these are open collector, so they need a pullup. I tried 4.7k on a breadboard, using some random pin (17) and it worked fine. Then I decided to make it permanent, soldered the resistors right onto the sensor's case, plugged the Sharp cables into pins 1 and 2 of the MSR1, mounted the sensors, and.... only one worked. After a lot of tinkering, I realized I had to drop the pullup resistor to a 2.2k on one of the sensors (the one hooked to pin 2). It works fine like this, but I'm very confused about the inconsistency.
Finally, I was able to interface a uOLED 128 display, but not in the way described in any docs, which insist on a pullup on the receive line. Also, I had to disconnect the reset line, which was causing weird resets. I basically connected everything straight (the display is 3.3v-5V tolerant), GND, +5V and TX/RX to 2 pins. It works 85% of the time, sometimes it does not come up, sometimes it goes into self test mode, etc... But this is topic for a different thread, as this is not as simple as hooking a voltmeter to check levels and the software part could have something to do with it (I'm using drivers from the OBEX that run on FullDuplexSerial.spin).
Maybe a separate section of the forum could be started for help with the MSR1, by people smarter than me (I am just an experimenter, a lot of people here really know how things work). I bought the board separately, knowing exactly what I'm getting into, but I suspect a lot of people have this board only because they bought the Stingray kit as an upgrade from the Boe-Bot, or maybe as a fancier starting robot (everyone should start with the Boe-Bot, that should be the law!!!), so they just read the texts and follow the standard 3.3v propboard stuff... Then they fail and say the Stingray/MSR1 is bad. Personally, I think the board is absolutely fantastic. I'm only using the 5V pins (as opposed to dismantling the translators) because I'm curious and want to make it work. This board actually helped me reduce clutter, as I'm driving two 12v gear motors and the electronics from only one 12v Li-Ion power drill battery, the voltage regulators and the dual h-bridge are awesome, very useful and quite tough (I put a heatsink on the H-bridge chip out of paranoia, but it never gets hot, although I never let it stall...). Also, kudos to Parallax for making these things so bloody rugged - I bet you half the stuff I connect to this board should not function and the amount of time I shorted things would normally end up in sparks and smoke, but these boards just keep going and going. The day they drop the price, I'll get a second one!
Hello everyone. The translators were original chosen to allow easy integration of 5V sensors onto the Robot Control Board, however we have obviously received much feedback indicating that there are some unforseen issues with the translators that have affected some customers. My best advice until we're able to provide a better solution would be to disable a bank of translators and use the pins directly, perhaps biasing a transistor to drive LEDs, or even in some cases for isolation.
If it seems like we're slow to respond to the issues related to this part it is only because we're currently working on possible solutions and want to update documentation once the issues are solved rather than making several updates with test information (things we're looking into). Please bear with us and we should have something early in January or know our timeline at that point.
My previous question was refering to the statement above... Any news?
Chris, not trying to be a pain, but I was hoping for a rework of the Stingray control board. Has anything come of it, or has the project been put on hold/cancelled?
I'm sorry everyone, we have decided not to update the MSR1 Board at this time. Instead we're going to offer the Stingray kit sans the board and at a greatly reduced price. Several customers expressed concern withus not having the chassis/motors available so they could put whatever microcontroller board on it that they wanted. Given the $299.00 price it just makes more sense to reduce the kit down to a simpler more widely usable platform and reduce the price by at least half. This will also broaden choices for not only sensors but battery packs and motor controllers.
If you have additional questions or concerns please reply and I will try to address them. I'm sorry we did not provide an update sooner.
@ erco - I second that... that thing is =fast=! (Or at least offer different gear ratios. Some younger folk might not mind running to catch their 'bot. ;-) )
Comments
I was also able to interface Sharp GP2D15 IR rangers. These are the digital type, instead of an analog value (like GP2D12), they just flip to a logical 1 (TTL levels, 5V) when an object is within a certain range (~9 inches). I know, I know, everyone swears by the analog one, but I needed these for bumper type object detection and nothing beats just checking a pin for 0 or 1, no need for comparators, DACs, extra cogs, subsumption, etc... just a plain old if/then.
Anyway, these are open collector, so they need a pullup. I tried 4.7k on a breadboard, using some random pin (17) and it worked fine. Then I decided to make it permanent, soldered the resistors right onto the sensor's case, plugged the Sharp cables into pins 1 and 2 of the MSR1, mounted the sensors, and.... only one worked. After a lot of tinkering, I realized I had to drop the pullup resistor to a 2.2k on one of the sensors (the one hooked to pin 2). It works fine like this, but I'm very confused about the inconsistency.
Finally, I was able to interface a uOLED 128 display, but not in the way described in any docs, which insist on a pullup on the receive line. Also, I had to disconnect the reset line, which was causing weird resets. I basically connected everything straight (the display is 3.3v-5V tolerant), GND, +5V and TX/RX to 2 pins. It works 85% of the time, sometimes it does not come up, sometimes it goes into self test mode, etc... But this is topic for a different thread, as this is not as simple as hooking a voltmeter to check levels and the software part could have something to do with it (I'm using drivers from the OBEX that run on FullDuplexSerial.spin).
Maybe a separate section of the forum could be started for help with the MSR1, by people smarter than me (I am just an experimenter, a lot of people here really know how things work). I bought the board separately, knowing exactly what I'm getting into, but I suspect a lot of people have this board only because they bought the Stingray kit as an upgrade from the Boe-Bot, or maybe as a fancier starting robot (everyone should start with the Boe-Bot, that should be the law!!!), so they just read the texts and follow the standard 3.3v propboard stuff... Then they fail and say the Stingray/MSR1 is bad. Personally, I think the board is absolutely fantastic. I'm only using the 5V pins (as opposed to dismantling the translators) because I'm curious and want to make it work. This board actually helped me reduce clutter, as I'm driving two 12v gear motors and the electronics from only one 12v Li-Ion power drill battery, the voltage regulators and the dual h-bridge are awesome, very useful and quite tough (I put a heatsink on the H-bridge chip out of paranoia, but it never gets hot, although I never let it stall...). Also, kudos to Parallax for making these things so bloody rugged - I bet you half the stuff I connect to this board should not function and the amount of time I shorted things would normally end up in sparks and smoke, but these boards just keep going and going. The day they drop the price, I'll get a second one!
Any update on the Stingray?
Polbit
My previous question was refering to the statement above... Any news?
Polbit
If you have additional questions or concerns please reply and I will try to address them. I'm sorry we did not provide an update sooner.
Amanda