Thanks to the readers and homebrewers who have contributed these helpful hints and corrections to the QuickieLab project, here are some Construction Notes that will be very helpful for those assembling the QuickieLab PC board.
PCB Modifications Required -- Several "cuts & adds" need to be made to the QuickieLab v1 PC board for it to work as designed. I had some problems when flowing the ground plane on the bottom side of the board during layout, and some errors went undetected when updating the prototype layout to the final production layout. Follow the graphic indications to get your board working like a champ!
Use of the DDS Daughtercard with the QuickieLab -- If you intend on using the DDS Daughtercard with the NJQRP QuickieLab, you need to cut the +5V trace on the bottom of the QuickieLab pc board that leads to P1 pin 4 on the DDS Daughtercard socket. This is because the DDS Daughtercard produces its own internal 5-V supply and doesn’t require that the QuickieLab supply it. This mod is indicated at position 9 on the pcb mods photo.
& Silkscreen typos -- The
posted schematic has been corrected, but you should
note the following if you are building up your QuickieLab:
a) C22 should be a 1.0 uF electrolytic capacitor. (This was previously noted as 0.1 uF.)
b) There are two "J12" designators ... The one for the Digital Pot (U6) should be J14.
c) There are two "R5" designators ... The one for the contrast trim pot by the LCD should be R14.
Operation & Orientation
-- Joe Everhart, N2CX
describes the operation of the LED/pushbutton arrangement, as well as how to
determine LED polarity ... "The LED/pushbutton connection provides 'double
duty' for the associated BS2 pins. If the BS2 pin is set up as an output
and it goes low, current flows through the 2K resistor and the LED, thus
lighting up the LED. If the pin is set up as an input, pressing the
pushbutton makes the pin go toward ground. (Without doing the math it goes to
just under one volt which is a logic '0' to the chip.) The LED also lights
while the switch is depressed.
"The 470 ohm resistor protects the BS2 chip. If the BS2 output pin was to be set 'high' by a program without a 470-ohm current limiting resistor being used, the switch would short the pin to ground which could zap that pin!
"As for pinouts on the LED, I can never remember which way they go, and indeed it varies from vendor to vendor. The cathode side of the diode usually (but not always) has a 'flat' on the lip at the base of the LED package - often tough for me to see without a magnifier! I always check polarity by trying the LED in series with a 1K resistor across a 9-volt battery. When it lights, the pin connected toward the + side of the battery is the anode."
LCDs that can be used -- Although the QuickieLab board was layed out specifically for an LCD from BG Micro (www.bgmicro.com, part # MDL 16264), any HD44780-based LCD should work just fine. It's the most popular type of controller for these LCDs, and each of the seven different ones I've tried it on work just fine. The pin numbers on the edge of the boards tend to be common among this class of LCD, but the connector locations unfortunately vary from top-to-bottom and left-to-right. So all the QuickieLab builder will need to do with a different display is to mount the LCD on standoffs and place 10 wires from the LCD down to J13 on the QuickieLab board. (You could use a makeshift connector that plugs into J13 by using an edge of a 28- or 40-pin machine-pin IC socket, or equivalent.) Just wire pin1 on the LCD to J13 pin 1, pin2 to to pin 2, etc. Follow the pins used on the schematic, as not all of the 16 positions are used. Also, some LCD's use pins 15 and 16 for the backlight supply voltage, but the QuickieLab board doesn't use this feature, so just leave those wires off.
Serial port via USB on XP -- Lee Mairs, KM4YY (email@example.com) tells us ... "I have an XP laptop that only came with USB ports. This shouldn't be a big deal because I have a Belkin FSU109 USB-serial prot adapter which runs fine when I use it to hot-synch my Palm Pilot IIIxe. Unfortunately, it will not always work right and when I posted a plea for help on the Yahoo Group for BASIC Stamps, several replies suggest that none of the Belkin adapters will work. I finally got a USB-to-RS232 serial adapter to work with the BASIC Stamp Editor and my XP's USB-only laptop. The IOGEAR UC232A-A ($39.95 at Micro Center) and the BAFO Technologies USB-Serial Adapter ($19.95 at TigerDirect.com) adapters will work with the Stamp Editor v1.33. You have to ignore the XP warning that the world will come to an end if you proceed with installing, but it worked fine."
Alternative #1 to BASIC Stamp -- As stated in the QuickieLab manual, Peter Anderson (http://www.phanderson.com) provides a "Homebrew BS2" chip set that costs about half as much as the Parallax BASIC Stamp 2. The good news is that we designed the QuickieLab PC board to accommodate this chip set approach to! Just put the Homebrew BS2 chips in the indicated positions on the PC board (and leave off the BS2 chip, of course) and operation will be the same as when using the BS2.
Space on PCB for
Peter Anderson's "Homebrew BS2" chipset -- Dennis
Rieger, KK5DB (firstname.lastname@example.org)
writes .. "I just received my QuickieLab. I also purchased Peter
Anderson's homebrew BS2. I originally thought I would have to build an
outboard circuit to connect it to the QuickieLab. However, it appears that
you have added the appropriate circuitry right on the board. Am I correct
or do you have other plans for this space? It sure looks like it will
work, but I haven't totally checked it out pin for pin."
You are right Dennis! I did accommodate use of the Peter Anderson "Homebrew BS2" chip set, but I neglected to put little asterisks on the parts layout for use of those parts. If you use the Peter Anderson "Homebrew Stamp" chip set, the following parts should be populated on the board: U1, U2, U3, C1, C2, C3, C4, C5, C6, C7, C8, R1, R2, R14, D1 and Y1. Populate components according to the schematic supplied in the Homebrew Stamp instructions. If you use the BS2 controller, leave those indicated positions empty on the PC board and use the BS2 in the U4 position. (NOTE: You cannot use both solutions at the same time). Have a look at the Board Layout graphic to see the Homebrew Stamp component locations.
Alternative #2 to BASIC Stamp -- Bob Confrey, WA1EDJ (Bob.Confrey@sciatl.com) from Atlanta writes ... "The Quickie Lab is designed for the Basic Stamp chip, but I was following some links on Peter Anderson's page and found the BasicX BX24 chip by NetMedia. While the Basic Stamp sounded interesting I found the BX24 was even better and actually the same basic price although P.H.A sells them for $44. The BX24 (actually an Atmel 8535) has 32K of program storage (about 8000 lines of code), 400 bytes of ram, has 8 built in 10 bit A/D channels and will do floating point math. It is fast too. Module is pin compatible with the Stamp. If someone was going to buy a BS2, I'd spend the $$ on a BX24. I got one about a week ago and been using it for some simple data logging projects, very easy to use. You can get just the chip for a little cheaper ($29). I ordered the BX24 from Peter via his Amazon.com shop and received it in an unbelievable 2 days! He is VERY good! His web page links to NetMedia and he has numerous examples of code written for the BX24 and BS2."
IOX Version Number Displayed -- The I/O Expander (IOX) chip U5 displays its version number on the LCD each time when power is first applied. Some earlier shipments of the IOX chip will actually display the version number as 0.9. This is okay, as I merely neglected to bump the displayed version number to 1.0 when we started shipments. But rest assured that all IOX versions are at the 1.0 level -- if you have a 0.9 chip it operates identically to the 1.0 version.
Alternate Mounting for the Speaker -- Dov Rabinowitz, AD0V (email@example.com) writes "One can mount the plugboard on standoffs, and then put the speaker underneath it pointing down (over some drilled holes) - this would protect it from damage. One might also be able to mount the DDS card in this space and it too would be more durable."
Use a 3-pin Socket for the IOX Resonator -- If you are into programming the SX28 device (used to provide the IOX function on the QuickieLab board), you might wish to use a 3-pin socket to mount the resonator. When using an SX-Key or SX-Blitz with your PC to program the SX28, it is better to remove the resonator because the programming cable provides the clock for the device being programmed.
IOX Frequency Counter Accuracy -- The accuracy of the frequency counting function in the IOX software may be improved by using a 50 MHz crystal in place of the resonator supplied in the IOX kit that most QuickieLab owners use. The resonator has a +/- 10% variability in its stated value, and since the IOX software timing is dependent on its clock frequency, the measured frequencies will correspondingly be +/- 10% from the actual values.
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