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    simple black/white detector without ADC?

    I have an interesting problem that I will put out to the community for suggestions. I would like to place a sensor over a black or white square (created using toner on a laser printer), and get out a ~5V or ~0V signal. I would like to use the QRD1114 IR LED/phototransistor combo if possible...
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    intermittent ps/2 keyboard problems

    So I'm attempting to use a ps/2 keyboard wired directly into a 28X1 chip for a project I'm working on. There are 10k-ohm pull-up resistors on the data and clock lines, and all of the connections appear solid (I measured them with an ohm-meter). It is powered either off of a 5V bench supply or...
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    i2c slave / scratchpad problems!

    So I am attempting to build a keyboard FIFO buffer using a 28X1 as an i2c slave to another 28X1. I developed a sort of handshaking protocol to let them exchange data: In the scratchpad ram, 0x00 = keyboard status byte (Empty=0, ready=1), and 0x01 = current character. Here is the code: '0x0 =...
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    bad luck with 28x1's?

    Has anyone else had really bad luck with 28x1's? After using tons of 08M's and 18X's for years, and never losing a single one, I've somehow managed to brick 2 28X1's while working on the same project! I don't appear to be doing anything unusual, but this is starting to drive me crazy! (those...
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    solve this and get a medal!

    Okay, this is one of the weirdest electrical problems i've ever experienced. When writing to an i2c FRAM chip (FM32256 from Ramtron), on a number of random locations (4,20,68,84,100,116,132,148,164,196,212,228,244 - in the first 255 locations), the 5th bit (2^5=32) is stuck at 0. I noticed it...
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    anyone tried a picaxe video game?

    I was fiddling around with a large LCD (24x8 character serial) I had lying around, and I was actually able to get a simple "PONG" animation displaying on it at ~10+ FPS (guessing . . . it was extremely fluid with no noticeable "flickering" or "jumping") with a 28x1 @ 16mhz. I know other people...
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    download problems at 16 mhz?

    Hello all, I just built a new 28X-1 board, soldered everything up, and tried to do a firmware check with the editor. All of the connections look fine on my multimeter, but no luck. The chip was initially connected to a 20 mhz resonator, so i thought that might be the problem, and unsoldered it...
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    Picaxe Laptop!

    Here is a DIY Picaxe-based "Laptop," built using an 18X chip and a 24LC512 i2c memory chip. It runs a simple assembly-like language, and includes the following software: * Text editor that can edit up to 4 different programs at a time * File manager with space for 10 ~1000 line programs *...
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    The picaxe can see!

    After entirely too many hours of work . . . behold! The first ever picture taken from a picaxe:
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    Generate +-9V?

    Hi, I'm trying to figure out a way, using 2 9V batteries, to generate a voltage sweep from -9V to +9V on an output. I would like a picaxe to sweep the voltage over about ~.5 seconds or so. Any thoughts?
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    Argg - hi2c slave problem with 28X-1

    I'm using a 28X-1 with the A.0 firmware, and version 5.1.1 of the programming editor. Reading from the chip works fine. Whenever I attempt to write to my 28X-1 chip, though, the data never seems to get written to the chip. I'm using the following code for the i2c slave chip: hi2csetup...
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    How to do a keyboard FIFO?

    I'm wondering if it's possible to build a picaxe-based FIFO for a ps/2 keyboard? Possibly using a dedicated 18X chip (does the Keyin command allow PWM to continue in the background? Also, can Keyin be halted by an interrupt?). I'm trying to come up with a way of making keyboard input more...
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    How to implement a For-Loop?

    Given 2 commands like: For(variable,start_val,end_val,step_val) Next(variable) How would one implement this, while maintaining the ability to nest them? my first thought was to store the following: -step size -variable -address of "For" command -address of command following the...
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    Anyone here ever written there own BASIC interpreter?

    Anyone think it's possible to write a sort of "meta-BASIC" interpreter using the picaxe "native" basic? I know I and hippy have both made assembly-like "meta-languages", but the 28X-1, with its 4k of program memory, makes me think this would be really possible (and...
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    How does the picaxe store numbers?

    I was wondering, how does the picaxe store numbers internally? For the "pause" command, for instance: Pause 5 = adds 1 byte to code Pause 16 = adds 2 bytes to code pause 255 = adds 2 bytes of code pause 256 = adds 3 bytes of code pause 65000 = adds 3 bytes to code I was thinking it...
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    Technical challenge!

    Okay, so now that I have my 24x8 character LCD working, I have a challenge for the crowd here: Is there any way to semi-reasonably display a 128x128 pixel image on a 24x8 character display? The "character" cells are 5x8 pixel groups, and they're unfortunately slightly separated. I can...
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    LCD broken?

    Hmm, so I purchased one of these 24x8 character LCD's off of ebay ( Whenever I power it on, though, all of the blocks turn on and come up solid, and I...
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    Arrrg, electrical interference problem

    So here is the setup: I have an array of 12 tiny solenoid valves mounted over a 36" conveyor belt that is being driven by a 1/30 HP, 90V motor (and is located about 8 inches from the valves). I have a chip (actually an FPGA) that outputs 2.5V for hi and 0V for lo, and is driving 12 NPN...
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    identify but can't download?

    So I have an 18X that will identify its firmware (8.6, btw), but then it gives me a "Error -memory verification failed (Byte 511)" message when I try to download. Any thoughts? I'm working on a kind of last minute project, so help is appreciated =)