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    Using a Picaxe and Mosfet to current limit a high power LED

    While a software solution may offer some benefits for a mass-produced controller, the concept is risky due to what can happen during code development. It is also very difficult to use ADC to measure the voltage drop across an LED driven by PWM, since the current is instantaneous during the PWM...
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    Bluetooth electronics App

    I agree with hippy. Those pause commands are resulting in the PICAXE skipping the successive characters. The pauses have no place in a program that is trying to receive serial data.
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    Macros within IF commands

    So both M2s and X2s use 6-bit tokens? I thought the Ms used smaller tokens.
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    interface with 3x4 keypad

    Your project is certainly doable. Note that the killer for interactive applications is using long pauses or blocking commands.
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    Is Hserin really this slow?

    I suspect that we are talking about different subjects. I have never used the foreground hSerIn because of the advantages I have found using background serial receive into the scratchpad (at up to 76800 baud). Also I rarely use asynch serial on M2 chips, preferring X2s due to their scratchpad...
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    spiin versus bit-banging

    @Aries, can you check what firmware your 20X2 is running? In the early days of 20X2s, there were a few issues with various peripheral modules. AFAIK these were resolved several years ago but I just want to rule that one out. (The current firmware for 20X2 is C.3)
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    Is Hserin really this slow?

    One of the problems with logging (with SerTxd) data received via hSerIn is that some of the benefits of using the hardware UART in the PIC/PICAXE get overridden by using the SerTxd command. The reason is that SerTxd's output is bit-banged, requiring critical timing for the serial bits to be...
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    How to Multiply PIN Toggles?

    You don't say exactly what you are trying to do. If it is to use a single command in your code to cause the 10 toggles or pulses, write a macro containing multiple PulsOut or Toggle commands in it. Implement it in your program code with a single command Eg. Toggles (10) Edit: Alternatively...
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    Using 2-lead bi-colour LEDs with PICAXE

    I realise you want to use around 100 R-G LEDs but you can cut the outer leads off near the LED body and solder fresh pigtails on the stumps. I've used this method on 3-wire RG LEDs before with the help of (modified) plastic jaw guards on a mini vice to hold the LED body, magnifying lamp and a...
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    I need to use the serin command for a fixed period of time.

    Yes, this problem comes up from time to time. Do a search of the forum using the key words receiver serin noise. I prefer to use the X2 PICAXE model's background serial reception capability, which allows you to search through the received data (or noise) rather than sit and wait for it to...
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    How to use serial commands for chip-chip communication?

    You can use one PE with two cables and two PICAXE windows open at the same time. Add the #COM xx directive to each program file to point them at their appropriate hardware.
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    How to use serial commands for chip-chip communication?

    The code above seems to be incomplete. How do you know that you are receiving 0 and 255? Timing is critical with serial communication. Deleting logging commands changes the timing and performance. Or are you using an oscilloscope to view the serial data received and the flashing LED? I have...
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    14M2 time-lapse controller

    Roughly (at temp rise of 70C!!!) you can get the following currents out of a ULN2803: 1 500mA (1 x 500mA) 2 800mA (2 x 400mA) 3 900mA (3 x 300mA) 4 1000mA (4 x 250mA) 5 1050mA (5 x 210mA) 6 1080mA (6 x 180mA) 7 1150mA (7 x 165mA) 8 1200mA (8 x 150mA) Note that you'd have to switch all the...
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    14M2 time-lapse controller

    Pen and paper is good enough if you do not have a software drawing package. Scan or photograph the drawing and post the picture. When drawing the circuit, try to keep the 0v line at the bottom and the +ve supply at the top. Convention also has the input circuitry to the left and outputs to...
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    08M2 and h-bridge SN754410

    From memory, the SN754410 is not recommended for use with PICs, including the PICAXE. I have successfully used L293 and L298 H-bridges with PICAXEs.
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    18M2 issue

    From my experience (and embarrassment:rolleyes:), PIC chips do not survive voltages over about 8v on their power supply or input pins. Anything over about 6v is high risk.
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    Pushbutton slew control with acceleration

    This code that I posted a few years ago is a good example of how you could structure your program.
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    Pushbutton ON/OFF

    I use bit variables to indicate the current state of the PICAXE. Events are used to change the state of these variables. Typical events are switch or timer state changes. Eg. 1. If an input changes state (button is pressed) when your timer is inactive, make something happen and enable the...
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    Trouble with PWMOUT

    Good to that you're now on top of the problem. Pin C.3 is a little different to the other pins on an 08M2. It does not have the internal protection diode between the pin and positive power rail pin. This is because in doubles as the Vpp pin, used to program the raw PIC. This may be why a...
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    Trouble with PWMOUT

    Time for some debugging. Add #Terminal 4800 to the top of your program, along with the other directives Add Pause 1000 as the first executable command at the top of your code (This gives the Terminal window time to open before the program starts logging immediately after downloading the...