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Do you really need a Raspberry PI to do all this? Wouldn't a low end 32-bit (even 8-bit) micro-controller be enough?
by pkaye 7y ago
Do you really need a Raspberry PI to do all this? Wouldn't a low end 32-bit (even 8-bit) micro-controller be enough?
- hanniabu 7y agoThe documentation, community support, accessibility, etc all make a difference in making RPI the go-to
- rullgrus 7y agoExactly. A low end micro-controller would do the trick but a Raspberry Pi is much more accessible - almost anyone can get one fairly quickly and if they themselves don't have the knowledge to do the setup they most likely know someone who can help.
- mrob 7y agoATmega micro-controllers also have great community support and documentation because of their use in Arduinos. If I was relying on an electronic device to protect my health I'd trust a simple 8-bit device more than something as complex as a Raspberry Pi.
- endymi0n 7y agoIf I was relying on an electronic device to protect my health I‘d trust my garbage collected code on a 64 bit ARM CPU using real CPU timers way more than my own ability to not segfault or OOM myself to death (literally) with low-level embedded C code. YMMV.
- zaarn 7y agoSegfaulting and OOM on MCU's is far more rare than on a device with an entire operating system on top. In most cases, MCU IDE's like the classic Arduino one don't even give you an allocator, all data must be statically allocated beforehand. IIRC it doesn't use the stack either. The main() and loop() functions initialize all their variables statically. When you have 2KB of memory to share between code, data and stack, allocating and using stack for function calls is luxury that only introduces problems. Hence, I've never ever ever seen an MCU crash from segfaults or OOMs. On the plus side they will also use vastly less energy. 10 Milliamps is enough to drive a ESP8266 or ESP32, in deep sleep you start counting microamps. A single battery cell can easily last a month.
- stefan_ 7y agoThis diagram of an open source pancreas has about 3 devices and 3 cables too many. A coin cell can run the control loop forever. I'm guessing industry hasn't produced this in a streamlined (reasonable) device because it will never be certified, and open source is just a codeword for subverting the regulatory process. Which, from a diabetes sufferer POV, is understandable. The dark cloud on the horizon is that if the FCC throws a hissy fit because you can install new software on your wireless router, imagine what the FDA will do if you market your device as compatible with this open source software that claims to automagically control your insulin pump.
- Adirael 7y agoThe diagram is a bit old. I use a closed loop system (Loop) and I just carry a RileyLink that bridges RF-to-BT so my iPhone can talk with the pump. No cables at all (and no infusion set cord if you use an Omnipod pump!)
- Adirael 7y agoThere are a few variants on how to do a closed loop system. OpenAPS is phone agnostic and everything runs on a RaspberryPi. I myself use Loop. It's an iOS app that uses a RF-to-BT bridge to talk with the pump and intercepts the CGM reading from the official Dexcom app (there are forks that support different methods, being the Dexcom source the "official" one). The bridge is the size of a 9V battery, I never stopped to see which processor uses but it's probably 8 bit. Each system support different pumps, sometimes people want to use one but are stuck with a different one to be able to use their pumps.