Did I kill a borrowed BOE-BOT?

ctdahle

On Friday a local college STEM program loaned me a BOE-BOT to play with while awaiting approval from the finance department (my wife) to order my own Boe-Bot kit. I am in the process of trying to find ways to bring micro-controllers into my classroom where I teach middle school science and mathematics, and I am hoping to hit up some local business people to make that happen.

I have had three days of success, learning my way around the BSE, writing simple programs, blinking LEDs and so forth. I have been very excited about this because the PBASIC programming, and the way the Parallax materials explain both software and hardware are far more accessible, especially for my 12-14 year-olds, than Arduino, and far more thorough than L*g*M*ndSt*rms.

This morning I began to work through the servo control activities and was making strides with the PULSOUT command when apparent disaster struck.

Here is literally what happened. I wired the board and uploaded the HighLowLed program from page 50-53 of the RWBB Manual. The program ran successfully. I modified it to alternately blink a pair of LEDs and uploaded that successfully. I stopped to refresh my coffee and then worked through the discussion of Servo Control. I typed up the PulseP13Led program on page 55 of the RWBB Manual and when I attempted to upload it, I got the No Stamps Found error.

The BOE is still able to run the modified HighLowLed program, but it will not communicate with any of the computers that it had successfully talked to over the last three days.

I have carefully checked all connections, swapped out serial cords, verified that my USB to DB9 serial converter is operating, and tried my children's older desktop computer that still has a DB9 serial port, all to no avail.

I was hoping to demonstrate this to some parents later in the week and gain their support before I approached the businesses, but now I am in a panic!

I'd appreciate any help at all but especially some from the Parallax people!

Mike Green

You might put a call in to Parallax tech support tomorrow. Things that can cause a "No Stamps Found" error that previously was working:

1) No power or weak power

2) Broken (intermittent) serial cable

Unless you loaded some new software onto your PC that somehow disabled or otherwise affected the USB to serial driver, it's unlikely to have to do with the PC end.

I can tell you this, but a phone call will be more helpful in terms of taking you step by step through the possibilities.

Franklin

How are you powering the BOE?

ctdahle

Mike Green wrote: »

You might put a call in to Parallax tech support tomorrow.

Thank you Mike, I will TRY to call tomorrow...unfortunately that's hard to do from a public school classroom.

1) No power or weak power

I was running the board on 4 freshly charged AA NiMH cells in the classroom Friday night. At home yesterday and this morning I was using the same 9v 300 mA wall wart I use with Arduino. After the failure, tried different power supplies, but no joy. With the AAs, I read 4.97 volts from Vdd to ground (Vss), and with the wall wart, I read 5.00 exactly.

2) Broken (intermittent) serial cable

I did try a different serial cable in addition to trying the BOE on different computer that did not need the USB to COM converter. I also did a continuity test on the cable.

Unless you loaded some new software onto your PC that somehow disabled or otherwise affected the USB to serial driver, it's unlikely to have to do with the PC end.

That was my conclusion as well. There WAS an automatic Windows update that loaded this morning, but the machine was not connected to my network at the time of the failure and the BOE was working on that machine AFTER the update. Before I tried the other computer, I disconnected it from the network so that it would NOT update just in case that was the problem.

I can tell you this, but a phone call will be more helpful in terms of taking you step by step through the possibilities.

Guess I will have to. I just don't know when.

I know that this board is a couple of years old, I'm wondering if they have an expected service life or a limited number of times they can be reprogrammed...I figure that is probably numbered in the 100,000s, but with a number of college students and public school kids having used the board over a few years, I suppose that might have been exceeded. Still, since it's borrowed, I guess I reasonably owe the college a new board...or at least a new BS2 module.

Mike Green

BOE-BOTs should last for years and years and Stamps can be reprogrammed at least 100,000 times. Even if it can't be reprogrammed, it can be "found" by the Stamp Editor and that's not what's happening with yours.

For a Stamp to be "found", the serial communications channel has to be working including the DTR control line. The Stamp has to have power because the identification process is an active one with the Stamp Editor and the Stamp carrying on a "conversation" with some checks for validity.

If the Stamp is "found" it should be able to have a new program downloaded since the process is almost the same.

Regarding the Windows Update ... You could always try disconnecting the USB to serial adapter, deleting the driver for it, and reinstalling a fresh copy from either the Parallax Downloads webpage or the FTDI webpage, then plugging in the adapter to finish the activation of the driver.

ctdahle

Mike, could it be possible for a "bad" USB-to-serial converter to send some sort of a signal or voltage spike that fried some part of the communication circuitry on the stamp?

I am thinking of this because I have an Inex "I-Box" (a version of a Logo Cricket) that stopped communicating with the PC about a year ago.

I had assumed that the I-Box was just a bad unit, but since it's failure was comparable to what happened to the BS2 yesterday (last program uploaded still functions, but no communications) with the only common factor being the USB adapter, I am now suspicious that the adapter was the device that committed the crime...a USB-to-serial killer.

ctdahle

Franklin wrote: »

How are you powering the BOE?

Franklin, I think I covered the power supply in my reply to Mike, but I do appreciate your willingness to help.

Mike Green

It would be very difficult for a USB to serial adapter to damage the Stamp. The Stamp's communications circuitry is designed for use with RS232 which can use voltage levels as high as +15V/-15V with respect to ground.

Your problem doesn't make sense. That's why you should call tech support. This sort of written slow step by step back and forth just isn't conducive to solving this sort of problem.

ctdahle

Mike Green wrote: »

It would be very difficult for a USB to serial adapter to damage the Stamp. The Stamp's communications circuitry is designed for use with RS232 which can use voltage levels as high as +15V/-15V with respect to ground.

Your problem doesn't make sense. That's why you should call tech support. This sort of written slow step by step back and forth just isn't conducive to solving this sort of problem.

I agree Mike, but I can't set up the Bot in my classroom and be on the phone with tech support during the school day. I teach from 7:30 AM until 5:15.

I have some free time on Wednesday afternoon and I am going to try then. Meantime I'm trying to cast around for answers on my own and I just learned something about RS-232 communication, even if it doesn't solve the problem.

Again, though, Thank you!

Here come the kids....

W9GFO

If you would make your location known there is a small possibility that someone on this forum would offer to assist, in person. For instance, if I saw that your location was Bellevue, WA then I would make such an offer.

Rich H

skylight

Could the baud rate have been changed?

ctdahle

Thanks Whiskey-Niner, I have added location information to my profile.

I'm going to a meeting of the local robotics society on Thursday and hoping for some help there too.

Cheers,

Chris

ctdahle

skylight wrote: »

Could the baud rate have been changed?

I suppose it is possible, but if so, it's not by any action I have taken. I assume it is supposed to be 9600. I don't have the gear in front of me right now, but I will check tonight.

ctdahle

Solved...I ran a second round of tests on a completely different computer and was able to verify a dodgy USB-serial converter. Odd that it would work on one computer's serial port and then not work on that same computer a day later, and that the USB adapter would fail at the same time.

ctdahle

One last update to this thread and then I will let it go. I borrowed several different USB to serial converters and was unable to communicate with the BS2 using any of them, but standard serial communications using the older computers available to me work just fine. One of the converters was an old Keyspan 19w that works with my Probeware kit, and the other is a "no-name" converter that shipped with my Dataq analog to digital data acquisition kit.

Anyway, I received my very own BOE-BOT kit today. I bought the USB version and it seems to work just fine.

I am grateful, and impressed with the the willingness to help expressed by people here. The positive, patient, and generous help offered to novices on this forum was one of the factors that convinced me to move forward with the Parallax products, both personally, and hopefully, in my classroom.

Now that I have my own BOE working, I am gearing up to build my first "serious" micro-controller project, a pair of servos which will work together to play simple songs on a child's toy xylophone...I call it the "Zweiservoglockenspiel-spieler". It should be a project that displays lots of blinking lights, movement, and noise, and is hopefully something that will draw kids into wanting to make a serious effort to learn about programming, electronics, math, and engineering.

erco

Many robots have two arms, so once you get your Zweiservoglockenspiel-spieler going, I bet you'll start planning a "Vierservoglockenspiel-spieler". .

Oder funf, sechs, sieben... alles ist gut, jah-wohl?

Mike Green

Have fun making your player.

I've used the Keyspan adapter (19w) with both a BOE (and BS2) and a Propeller and it worked fine for me. Make sure you're using Keyspan's driver, not Windows'.