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Pico, since these should align to the default I2C and SPI peripherals used on the Uno (and thus the Seismograph libraries and sketch). This should minimise the code changes that might be needed. Assuming you are using the arduinopico package, this will involve using the likes of Wire.setSDA() and Wire.setSCL() for I2C and SPI.setSCK(), Advertising Index Altronics.................................31-34 Blackmagic Design....................... 5 Dave Thompson........................ 103 DigiKey Electronics..................OBC Electronex................................... 11 Emona Instruments.................. IBC Hare & Forbes............................... 7 Jaycar............................. 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Expect postal delivery of subscription copies in Australia between April 27th and May 12th. 104 Silicon Chip SPI.setRX() and SPI.setTX() for SPI. We’d probably put them right at the start of setup(), so they are set before any of the peripherals start up. As you say, the Pico or Pico 2 will be much more capable than the Uno, so we wouldn’t bother with splitting routines over cores. We wouldn’t be surprised if there are some other subtle changes that cause things not to work. We’ve had some odd issues with different versions of the SD card libraries, although the fact that it is compiling is a good sign. We updated that project in April 2019 (siliconchip.au/Article/11532) to use a geophone sensor (still using the Uno). The geophone is a purely analog device, so shouldn’t present any difficulties in interfacing, although we did use the Uno’s ATmega328 1.1V analog reference, which the Pico lacks. So there might need to be changes to get this version functional, but they should not be difficult. One thought that comes to mind is to use a Pico W and make the contents of the SD card available on a web server so the card doesn’t need to be removed for reading. This would be a similar concept to that used in the WiFi Weather Logger from December 2024 (siliconchip.au/Article/17315). Battery bank inverter efficiency Some years ago, I assembled the Appliance Energy Meter (July & August 2004; siliconchip.au/ Series/96) from an Altronics K4600 kit. I’ve been using it around the house to measure the energy use of various things. I recently purchased a Bluetti AC70P battery bank and am testing it using my car fridge. I’m using the AC power brick that came with the fridge, which has an input power rating of 220-240V AC 0.6A. The output of this (transformer-­ based) AC-to-DC converter is 12V DC at 5A (60W). When the fridge compressor is running, the energy meter shows a draw of about 56W; however, the Bluetti AC draw is showing about 96W, a factor of 1.7 higher. I would appreciate if you could comment on the accuracy of the Energy Meter. I’ve never had any reason to doubt it in the past. To explain this difference, I suspect that the energy figure shown by the power station is the actual draw Australia's electronics magazine from the battery, and the AC inverter is very inefficient at this low power draw. I would appreciate your comments on this line of thinking. 58% efficiency is low, but the AC inverter is rated at 1000W, so I guess that would be reasonable. I will investigate using the 12V 10A supply on the AC70P. This may be a more efficient use of the available battery watt-hours. (B. P., Jeir, NSW) ● That Energy Meter design should be accurate to <0.5% when calibrated. You certainly should expect the battery to be supplying more power at the inverter input than the appliance is drawing at the output. If you have something like an incandescent desk or floor lamp (or perhaps halogen) that you can use as a test load, run it from the inverter and make the same measurements. See if you find a similar amount of lost power (40W). That is enough to make something pretty warm. If left running for a while, does the inverter case temperature go up noticeably? An inverter can be expected to consume at least 10W internally, even with a light load. The lost power will probably be some fixed amount (say around 10W), plus a percentage of the load current (perhaps 10%). That implies it would be less efficient with a light load. Still, 40W seems like quite a lot of wasted power. It is possible that the battery bank power meter is not 100% accurate. Visual doorbell alert wanted for the deaf I have enjoyed your articles for many years. I am deaf and need some help to design/build myself a doorbell button to trigger several flashing lights simultaneously in several rooms in my apartment as I cannot hear audio door chimes commonly installed in homes. Jaycar sells 433MHz receiver and transmitter modules. I don’t know what decoder/encoder I need for this project. I am open to suggestions. (Anthony, via email) ● We have published a suitable project in the January 2009 issue, titled “433MHz UHF Remote Switch” (siliconchip.au/Article/1284). That back issue is still available to order, and programmed microcontrollers for this project are available from our Online Shop at siliconchip.au/ SC Shop/?article=1284 siliconchip.com.au