Recent content by papaof2

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    Speed counter

    Perhaps start with an accurate source of time, such as the DS1307 or similar? To know how many revolutions per minute, you need an accurate minute to frame your revolution count. You will need a PICAXE that supports I2C to talk with the DS1307 and most other clock chips. The DS1307 keeps time...
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    Servo linkage headache

    Why not mount the box directly to the servo? If the servo can't support the weight, use gears to turn the box on whatever mount it needs. If you need large, inexpensive gears, look for a discarded bicycle. Perhaps use chain drive with bicycle sprockets? The chain drive could also provide up...
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    Showing multiple messages on an OLED

    How many characters do you need to displayfor each alarm? If less than 8 characters, use screen addressing and place each of the 4 alarms in its own quadrant. "HI TEMP", "LO TEMP", "DOOR 12" are each 7 characters. If the alarms need 8 or more characters to identify them, display alarms 1 and...
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    Fluke 21 Multimeter died.

    They make an inexpensive meter for testing electric fences up to 7000 volts. In the US, you'll find it at your local Tractor Supply or online at
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    Fluke 21 Multimeter died.

    First you need to know the peak voltage of the fence charger and the maximum input voltage of the Fluke. Unless you have a genuine technical need to know the exact voltage, a series string of neon bulbs (NE-2 or the like) needs about 90 volts per bulb to light it. For 2000 volts, that's 22...
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    Windows 7 alternative?

    While I have Win 10 (formatting ebooks for Kindle) and Win 7 (monitoring the solar power system), I still have an XP laptop that I use for writing those books because I like the screen and keyboard on the ancient (12 years old) Dell D620. XP has been "not supported" for several years and while...
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    Solar powered robot - Charging suggestions requested.

    Most consumer GPS units are not high resolution (1 meter or less). While there are some VERY accurate positioning devices (the ones used to steer tractors so all the plowed rows are straight and equally spaced), those are also VERY expensive. For getting the location in a garden, there's...
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    Solar powered robot - Charging suggestions requested.

    My preferred method of choosing what solar panel(s) is to first go to and enter the exact location to get the available sun hours by month and panel tilt. Seasonal differences matter for some things and 3 hours in December versus 5...
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    Constant wattage load for discharging a battery

    I looked online for a constant current load to test some PV panels. If you search for constant current load or constant current discharge you should find several versions - some much simpler than others. Don't remember where I found it, but the attached is one of the simpler designs. If you...
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    Micromega now has a 64 bit FPU

    I saw the press release for the uM-FPU64 today. It has 64 and 32 bit floating point and integer math, foreground/background operations, local peripheral control - it can control I2C and SPI devices, 9 or 23 digital I/O pins (depending on the package), servo control, and lots of other "goodies"...
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    If you really really need a low power device

    You never know what may turn up on - this week included a microprocessor experimenter's kit for $4.30US, so I followed the link to see what the chip specs were. The 16 bit TI MSP430 series power requirements: 0.1-µA RAM retention 0.8-µA real-time clock mode 250-µA/MIPS active...
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    Anyone used the TMP102 I2C temperature sensor?

    Saw this on SparkFun A quick scan of the datasheet (link on the page above) shows specs similar to DS18B20, but the interface is I2C at 400kHz plus high speed: 3.4mHz. It works in uamps and gives the temperature in less than 50...
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    Problems with uM-FPU v 3.1

    This is my first time using the uM-FPU. I have an EM-406 GPS connected to SERIN of the uM-FPU and have adapted the GPSdemo.bas program from MicroMega to work (some of their original definitions are no longer available, such as SWAP, SIN, ATAN). The problem is the instability of the...
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    DipTrace library with 40X2?

    I looked through the libraries I have downloaded (thanks to all the people who contributed) but did not find a 40X2. Did I overlook it, is there a newer library (mine were downloaded sometime last year), or do I need to learn how to create my own components? Thanks, John
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    Rising water alarm - sump pump controller

    After the basement of our daughter's house was flooded because of a stopped up drain in an outside stairway, I used a PICAXE08M and a float switch to build a water alarm and pump controller. The pump controller proved to be overkill and was not installed, but the alarm has already saved the...