Hack Correlation

As I wrote in the previous article , the barebones design has been through some basic testing - 500km mixed environment driving - and has been mostly successful so far. I had a suspicion that the output impedance of the circuit must somehow match a known impedance, but was not sure which. The clue was that the RaceChip unit raised city consumption by 5-15% even though it had no effect during the bench testing. Here's a datasheet for a similar Bosch pressure sensor: http://rb-aa.bosch.com/boaasocs/index.jsp;jsessionid=A20738712FCFB9E51CA919DD7D2F9E91.sundoro2?ccat_id=275&prod_id=516 For testing they are using a pull-up resistor, so on the input side of the ADC the same circuit must be simulated in order to drive the sensor. I used a 10k resistor, but perhaps even the internal pull-up could work. At the DAC/PWM output I found out that a 1.5k resistor was too large and could not sink the ECU input line low enough. With a 10ohm resistor it seemed to work fine, perhaps 47oh...

There are many variables needed to get a reliable product, so while taking a break from the ISO automotive requirements I thought of playing with a barebones design - just an Arduino, an HC-05 module and perhaps a few passives. Concept - this is similar to what the boxes on the market do - read the value on ADC, output the modified value with PWM. I'm using an Arduino Nano for this, took about half a day including the 'preview' spreadsheet. Nano pinout: Vcc to sensor supply (5V), from ECU GND to sensor ground A0 the output from the sensor Pin 9 goes to ECU (former sensor data) TX goes to RX of HC05 RX goes to TX of HC05 Notes: A0 should probably be pulled up to Vcc through a 1k resistor, I haven't tested this yet. Perhaps the Arduino weak pull-up would work. Pin 9 (PWM output) should go through a resistor and capacitor connected to ground, 1k with 0.3u looks good in my tests. The first two pictures show the Android phone connected to th...

As seen from my previous post and the sources enumerated in it there are several competing designs on the market that basically achieve the same thing - apply a negative offset to the rail sensor voltage. Since none of them offer a desirable amount of control (for the price) I'm open sourcing an own design. Goals: full programmability - curves, upper and lower threshold limits telemetry reasonably fail-safe MCU agnostic - as far as possible preserve the original waveform signal easy to make - should not require exotic or expensive components The overall architecture is simple: read sensor data into the microcontroller, process the signal, send an analog (PWM) signal out. Disclaimer: this is probably not road-legal in many countries (missing certifications) and it might break the car subject. I am not responsible if anything bad happens, do it at your own risk. However, it's not all dark, as I've already written there should be no damage as the unit still ...

See my first article for a short review and teardown: http://hackcorrelation.blogspot.de/2016/02/inside-stuff-racechip-car-tuning-thingie.html First off let me start by saying I consider this fair use, as the instructions and website do not explain what the settings do, how the unit actually functions and what effects it can have. The description below refers to a single-channel Diesel engine (single common rail). Settings First off, most of the users will just want the simple explanations, here's a graph that should be in the manual: The chart above shows 4 possible settings and their effects. The first rotary encoder controls how much 'extra power' is requested. See 9E vs. BE vs. 4E The second rotary encoder controls the RPM high range (endpoint). See BE vs B7. The encoders go from 8 (minimum) through 9, A, B, C, ..., F, 0, 1 ... 7 (maximum).

I bought a cheaper-than-usual Ricoh / Pentax GR APS-C camera on ebay that had a few minor issues. One of the most visible ones was dust on the sensor, so I will show you two methods that I've used to clean it up - the hard way first , followed by the easy way . First, to get the position of the dust spots a shot was taken with F/16 against a white background. The exposure was manually set to be as high as possible (while still retaining information), pre-focus was set to the closest position (macro). The resulting image was then adjusted in Irfanview (Auto adjust colors) to get the highest contrast. F/16, 1/3s, MF to closest position Preparation You need a very clean room, no dust, have a dust spray available and preferably wear gloves to avoid getting fingerprints. All parts that cannot be cleaned after assembly (LCD cover backside, LCD, sensor) should be placed facing down on some lint-free material. While removing the screws take note of their length, color and...

In search of a cheap and light notebook that I can use it for light tasks - such as Udacity courses and connecting lab equipment - I stumbled upon Odys Winpad V10 on offer at Amazon. While the Lenovo Miix 830 seemed like a good deal at the moment it suffers from poor battery life, limited USB connectivity while charging and lack of keyboard+touchpad. Most Bluetooth keyboard with trackpad on market now have issues and are overpriced, so the Odys seems like a good fit. This is a short review followed by a look inside the 'docking' unit. Initial impressions The unit is very heavy for its size, ~670g for the tablet and ~670g for the keyboard. The keyboard/touchpad base does not contain any other batteries or peripherals. Battery life is pretty good, I got >6h for light work and the battery bar estimated >14h while idle and connected to the HDMI output with the tablet screen off. The built-in touchpad is pretty bad - the bottom touch area is reserved by the left ...

I wanted a second try on my bench power supply build, something that would allow me to programmatically control the output voltage via an 'Arduino'. The supply already has two buck converters inside the unit, both controlled by their feedback resistors, so it was only natural to try to create a programmable resistor. Resolution The feedback resistors are in the potentiometer with ranges a few kiloohms. Since I'd like the output voltage to vary within 0 and 30V with a 50mV precision the needed resolution is 30/0.05 = 600 steps. That means a way to vary the output with 10 bits (1024 steps). A cheap 8-bit DAC ( PCF8591 ) would provide a resolution of only ~120mV. We should not confuse resolution and precision, but I will break the rules for now. Why a DAC does not work Third, just a DAC is not sufficient as we need to have the feedback voltage adapt to the output voltage. We could feed the input through and ADC, sample it, calculate and output the correct DAC value ...