Recent content by Andrew Cowan

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    Wireless control in a noisy environment

    One of my latest projects is a RGBY LED floodlamp (for lack of a better word). I've built a wooden box which houses twelve 4W RGBY (red, green, blue, yellow) LED modules. These have built in constant current drivers with PWM. Control will most likely be a 28X2. Power is provided by a decased...
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    LED fader

    My current project - a four channel RGBY LED fader. I'm using a 28X2 at 1MHz in order to get four PWM channels at 98Hz. The finished project will be much more complex and controlled via a radio link, but to start, I'm trying to write a fading subroutine. I'm not worried about the fading rate...
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    Bit banging PWM

    I'm looking to control some RGBY LED modules via serial. These modules have built in CC drivers, and accept a PWM input of up to 2kHz. However, the inductors buzz/hum at whatever PWM frequency is used, so a 2kHz PWM results in a 2kHz hum. Through a bit of trial and error, I've found the least...
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    9 PWM channels

    I'm working on another RGB LED project, and I require three sets of LEDs, so 9 PWM channels in total. I don't really want lots of PICAXE chips, so I'm looking for an expansion chip (serial, SPI or I2c - I don't mind). Has anyone had any experience with any output expansion chips (supporting...
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    OT: Preventing motor damage

    I've got a quick query regarding motor control. To control the angle of a camera, I am using a geared motor, potentiometer for feedback, and a PICAXE running a PID control loop. That all works fine - the system responds to an rc input. The motor is a GM21 Gearmotor - with a 360:1 gearbox, it...
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    Do-able by an 18M2?

    I'm working on a radio project, that requires me to generate a PPM pulse stream with the following timing requirements: 400uS Synch pulse 600-1600uS pulse for channel 1 400uS Synch pulse 600-1600uS pulse for channel 2 400uS Synch pulse 600-1600uS pulse for channel 3 400uS Synch pulse 600-1600uS...
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    Controlling a HT1632C

    Browsing around Sureelectronic's website, I've spotted their 32x16 dot matrix bicolour LED display pannel. If a PICAXE can handle it, I'm looking to get two, connected to form a 16x64 LED pannel. Each display is run by four HT1632C driver ICs - (display datasheet). Each HT1632C has 32 byte...
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    20X2 = 14X2 and 6X2

    Running out of code space on a 14M, and not having space for a larger chip, I've taken Dave E's idea and converted a 20X2 into a 14X2. Works perfectly! Andrew
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    14M storage locations?

    I have a circuit with a 14M in, in which I need to store 18 bytes of data (which change throughout the program). Obviously bxx variables are not enough - there are only 14 of them. Are there other locations that I can use to store bytes? I'm thinking peeking and poking is the answer, but I...
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    Planning to order a new 20X2 (SMD)

    I'm using a (smd) 20X2 in a project which communicates with an serial LCD (with a crystal for timing), with another 20X2, and via a serial radio link. However, the 20X2 requires calibfreq -5 to communicate with all these things (especially the screen), and even then there are errors. I know a...
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    LM2575 regulator shutting down

    Apologies for the non-PICAXE question. I've got a LM2575-12 switching regulator stepping down from 24v to 12v. I've followed the example circuit exactly, and it worked fine with a previous 12v camera. However, I've upgraded the camera, and come across a problem. Background: The camera runs...
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    Control of Trisate pins on a 14M

    I'm trying to bit-bang I2C on a 14M (with much help from hippy). His code (designed for the 08M) uses plenty of 'Input pin' commands to set the pin to high impedance. However, I'm using the 14M, which doesn't support the Input command. Is there anyway of controlling the state of one pin...
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    I2C on a 14M

    I'm upgrading a circuit board which used to talk to an ultrasonic range finder (via pulse widths). However, I have upgraded to using an SRF235, which uses I2C. It has four registers, one to write to, and two two read. The other is unused. However, my circuit board has 5 other PICAXEs on, and...
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    Choosing a Fluke multimeter

    Sorry for the off-topic question (hey, it's all electronics!). My position: I currently own a high end (compared to your average £5 multimeter) model - a WG020. This multimeter does everything I want it to, and I am happy with it. I feel that at some point in my electronics career, I will...
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    parse test

    :p :p test