For some reason the 47 pF value for the caps is sitting in my mind. Either after 'calibration' the LC meter is so far off that it read both my TI-89's and my V200's caps 51 pf, both ~8% high, or both of them are within their 10% tolerance and reading...
Putting everything together also requires checking everything separately first. So I did with the MiCS-VZ-89T sensor, and here is the story, also presented on my blog: MiCS-VZ-89 Air Quality SensorA low power sensor that can measure at the same time...
The PCB arrived and they look perfect, not that I had any doubt when ordering at a big Chinese manufacturer. And of course there are mistakes :/ The voltage regulator for USB power to the GPS chip U5 has the wrong footprint. I used a SOT-89-3 foot...
Requirements Easily found when misplacedBig enough to hold easily but not too big that it's cumbersomeShould have a battery compartment so that unskilled personnel can replace batteries without having to open up the housingRoom enough for the necessary...
I've redesigned the way screens/apps are handled and introduced a main menu. More importantly, I have managed to get the average current consumption down to 350-550uA (1.5mA previously)! Turns out a huge chunk of it - 800uA, was a bug in the TWI (I2C)...
After a sinuous but exciting road, the Beta prototype came out nice, the entire device is amazingly small: I was able to design it to fit the 110x70mm aluminium enclosure I planned initially without renouncing to any of the sensors nor reducing the 1500mAh...
On my TI-89, one of the battery contacts on the PCB was heavily corroded and it took a good deal of time and heat to reflow solder to make a new pad. I did this to the V200 as a preventative measure too, but I guess I heated up the nearby fuse to where...
PCB Rev 1 are working and usable but there is room for BOM cost optimization. Current sale price could be 89 EUR, with extensive BOM optimization it could be lowered - hopefully. USB micro-B to USB mini changeFTDI USB connector is currently micro-B footprint...
When the first ideas for this Cyerdeck came up, I was already sure to create it modular, as much as possible. As such I had defined the following requirements for myself:All "Modules" MUSTbe easily replaced for future improvements, modification...
With the wiring complete I wrote a small program in Python to test the lights, buttons, and switches on the front panel. To be clear this is NOT the KENBAK-2/5 emulator running a program (yet). As it turns out I did have to replace one of the LEDs...
15 July 2018 First a word about packaging. I designed the BQ25504 breakout board to be as small as possible because I had in mind the idea that it would become part of an integrated (hybrid) power source. That is, the LiPo battery, solar cell, and BQ25504...
I promised this log for several times and now it is finally here. Let's start with how a rising edge looks.RisetimeThe orange and light blue ones were measured using commercial devices, the Agilent 86100C and LeCroy WaveRunner (this one was already mentioned...
Version 1 of the hardware arrived, and I have been testing it. Almost immediately, I discovered I had made a connection mistake on the 3.3V regulator, and the system would not run normally from battery power. I desoldered that part, and by providing...
lBefore I can get my hands on more numbers from the scan, let's go back to 147. C-ving. For the prime 1511 and higher, there is not enough data to get a complete histogram and there are histograms with 3 holes. We already know that the holes are symmetric...
IMU functions The Arduino 101 Inertial Measurement Unit is fully documented and works well. For the fall detection, the software detects a short period of freefall followed by a shock. Both events are handled via callbacks: void imuInit(void) {...