Raspberry Pi Forums

Gert van Loo

The solution with the lowest high which is still a removable connector would be
SMD female "bottom entry". With that I mean a connector which is normaly
surface mount soldered down but the pins enter from the ''other side'' (bottom) of the PCB.

Gert van Loo

A USB-to-Serial-converter is exactly what I am using in the demo ( http://youtu.be/qnr7AlwMDPc ) There are several different types, 5V signals and 3v3 signals. You need to buy the 3V3 version. Both types output 5V on the (red) supply wire. I even have run two Gertbots from one USB cable although acc...

Gert van Loo

Yesterday I ran a 28BYJ48 12V from the Gertbot.
The Gertbot can easily go up to 5000 Hz but I found the motor would stop rotating above 300Hz.
Torque seems best around 200Hz. As it has an internal gearbox of 63:1 you get max ~ 5 RPM out of it.

Gert van Loo

Switching power off without shutting down CAN upset your SD-card It has happened about three times to me in the years and each time it took me quite some time to get back where I was.** So I always try to shut-down beforehand. Unfortunately that is not always possible, especially if the image did no...

Gert van Loo

You have to get a datasheet of the LCD display which tells you how it works. Alternative is to find out what chips are used internally and get the datasheet for those but that requires that you know how those chips are connected to the display and what they control. Otherwise there is very little yo...

Gert van Loo

Yes, you can replace it. I have tried the 12-bit when the others where not available.

It should be possible: 10K * 12 bit is 120Kbits/sec and the SPI can easily run ten times faster then that.
But beware that due to the non-real time behavior of Linux you might not get equidistant samples.

Gert van Loo

I have been reading up on that subject.
The voltage limits are not hard as they differ from person to person.

It seems 36V is the safety limit for AC and 60V is the safety limit for DC.

Gert van Loo

Use the Arduino watchdog :-) So your Arduino can recover if the I2C bus hangs (e.g. if you stop the master in the middle of an I2C cycle) I have built some I2C interfaces. I always added a time-out register so the interface would recover if the clock stretching was going past some set time limit. e...

Gert van Loo

A very, very good method of EMC protection and from picking up spikes is to put capacitors between the wire and ground. This solutions is too often forgotten maybe because you can not use this if there are high frequencies going over the line which indeed is the case with most interfaces. But for si...

Gert van Loo

The Host Interface might also do what you want. It can be configured to do DMA transfers on a single 16-bit-wide channel, and the hardware supports the scheduling of transfer blocks for you. But I'm in the same boat as Gert and James so I'm just going by my fading grey cells..... Neil There is the ...

Gert van Loo

Yes, I know about it. But as I no longer work for Broadcom I do not have access to the documentation anymore. You will need that for the details but to be honest: the last time I used the interface the documentation of the SMI is not that great. Good for some coarse idea but lacking details which to...

Gert van Loo

It is unlikely that somebody is driving 1.65V. Try to find a resistor which leads to the LED and measure the voltage on both sides.
You might find a much higher switching voltage!
If not: try to remove the LED. There is a good chance that afterwards you get a full 3V signal swing.

Gert van Loo

My Mantra If you think you are ready to work with mains voltages, you are not.
I was lucky enough to survive the two times when I was younger and proven to be not ready......

Gert van Loo

The difference is mostly there for the lawyers.

With supply I might be taken to court for any damages as a result from normal usage.

If you connect an external voltage, that is a modification and I am not responsible if user(s)
make modifications to the products.

Gert van Loo

As you might have seen from today's news. The Gertbot has a DCC mode and plugs on top of the PI. All it requires is a 15V DC supply. The board has four independent channels, each capable of supplying 2.5A. You can cascade up to 4 boards giving a total of 16 DCC channels. There is even a GUI applicat...

Gert van Loo

You have to write a program to read the RTC and display the result on the LCD.
To start with it will be something like:
while (1)
{
time = read_real_time_clock()
display_lcd(time)
}

Later you can think of how to make it more clever and power efficient.

Gert van Loo

Yes. If only the Gert VGA board actually existed (as a consumer product)…

Just give it time.

Gert van Loo

mahjongg wrote:there is no way any GPIO can output 5V.

Welll.......
There was this guy who connected 24V to the 5V supply.

Gert van Loo

fruitoftheloom wrote:Not a hope, there is no way to undertake what you want

I don't know, how about this:
1/ Start with taking an Intel I5 mother board.
2/ Locate the 5V supply.
3/ Connect it to a PI.

Your are 90% there!

Gert van Loo

I'd really love to have usbboot for Windows and be able to flash the MMC from Windows. Is there anything available yet? If not, can anyone help me with the required Broadcom drivers, so i could start developing such a tool? Regards, Peter Just wanted to check: I assume you mean "I'd really love to ...

Gert van Loo

The LED's are normally lit up. I can't debug much from here as I can't see what you are doing (...wrong?) 99% of the errors are caused by wrong wiring. Check your wiring! It sound trivial but checking wiring or any other circuit you have made, is very difficult. It seems once your brain has gone: 't...

Gert van Loo

If you do not see the board in the IDE you have probably forgotten to edit the boards.txt or programmers.txt file. Setting up everything so the Gertduino works is a lot of work. I tried to make it easier by providing a Makefile with instructions here: http://www.raspberrypi.org/forums/viewtopic.php?...

Gert van Loo

Hi I'm going try and build my own. To avoid the problem of drawing more power than the Broadcom specs say you should for the HSYNC and VSYNC I was thinking of using a transistor and the 3v3 line. What value resistor would give the necessary current that the VGA specs say HSYNC and VSYNC? I've tried...

Gert van Loo

Interesting anecdote: that colour connection table is NOT in the 2835 datasheet. I wanted to add that to my document and nobody knew the details. So I had to ask my ex-colleagues at Broadcom for the original chip Verilog code. I send an email which went like this: "Can you send me the DPI colour mul...

Gert van Loo

... and another possibly silly question from another RISC OS user ... Gert's PDF states: You select the mode using: dpi_output_format=X (X in range 1..7) The VGA adaptor PCB is designed up for mode 5. does this go in config.txt? Yes, it goes in config.txt And if I choose a different format, with fe...

Search found 2081 matches

Re: GPIO connection with insert-able pins

Re: Gertbot - USB to Serial converter

Re: Stepper Motor 28BYJ-48 5V - lack of torque?

Re: on off switch

Re: getting touches via I2C

Re: 12-bit ADC on gertboard?

Re: Raspberry Pi + Arduino

Re: I2C clock stretching

Re: Protect raspberry pi against voltage spikes

Re: SMI Documentation ?

Re: SMI Documentation ?

Re: Door bell project - technical questionss

Re: Raspberry Pi + Arduino

Re: Power Supply

Re: Pi = DCC for model railways?

Re: Alarm Clock/Timmer

Re: Duel video output

Re: 5V coming out of GPIO17 by default?

Re: Processor,Ram and Gpu Upgrade?

Re: USBBoot for Windows

Re: Questions about the buttons test and my Gertboard

Re: Program Atmega328 with the Arduino IDE and setup atmega4

Re: Gert's VGA add-on for the B+

Re: Gert's VGA add-on for the B+

Re: Gert's VGA add-on for the B+