I don’t think so. Each
I don’t think so. Each reflectance sensor drain 25mA at 5V. Then, seven sensors drain 175mA at 5V. Added to this we have the motors current (I don’t measure it yet, but certainly it’s exceed 80mA each) and the 3.7v@200mAh is not enough to maintain the whole system. The new design that I have made, have a MOSFET gate to enable the IR sensors only when I needed them. This ensures more life to the system.
Now there’s a slick little
Now there’s a slick little fellow! 
Pocket sized robot!
I can’t understand very well
I can’t understand very well what you said: your question is about a programmer (hardware that program the MCU) or a program (code software). Please, explain more…
Well you could, but it
Well you could, but it would only last a few minutes 
When you have a 3.7v@200mAh,
When you have a 3.7v@200mAh, you have a 740mWh of power (theorically). If your system drain more than 200mAh, 400mAh for example, your battery (that still have a obligation with 740mWh), then the 3.7v step down to about 1.85v, to keep the power compromise. Your board, now, couldn’t have nough voltage to operate. Because that, your board never work, even for a few seconds.
I can’t catch what you said
I can’t catch what you said
Please, explain…
programmer as in the
programmer as in the hardware. sorry for my poor explanation
other than lipo (its too
other than lipo (its too dangerous and expensive) any other lightweight and compact battteries that i can use?
Lithium Ion batteries,
Lithium Ion batteries, although those are somewhat dangerous too. You will probably have to go for a small NIMH battery pack, AAA or smaller.
That would be really nice!
That would be really nice!
would this work? Pololu
would this work? Pololu item #: 1170
Yes, work. But I don’t think
Yes, work. But I don’t think that LiPo is so dangerous…and the sizexpower is very atractive. USB charge so.
isnt there a risk of
isnt there a risk of catching fire? what charger do you use? could i see your schematics ? thanks
Yes, but only if you use a
Yes, but only if you use a poor or incorrect charger. I make a charger for my use, using MAX1811, that can handle both Lithium Ion and Lithium Polymer battery. The schematics you can below:
Theres a entry on my Blog for that. Now I made a USB stick version:
It’s a really good charger, with some useful things, like:
- You can select between 4.1v and 4.2v battery regulation point;
- You can select between 100mA and 500mA current drain from USB;
- There’s a open drain pin (pin_8) for signaling end of charge condition (2.5V < VBATT < BATT Regulation Voltage);
- A internal thermal loop limits the MAX1811 die temperature to +135°C by reducing the charging current as necessary.
Awesome. But, in the definitive design of GUI, I use the MAX1555, because it’s small package (SOT23). PCB space is a concern to me in this project. The only drawback is that MAX1555 limit charge current to 100mA only, and the charger time going to be more than in my first MAX1811 charger.
When you use a bootloader,
When you use a bootloader, you don’t use your programmer ICSP anymore. These are some steps to work with bootloaders:
- After a new MCU is bought, choice a correct bootloader .HEX file for it. Observe what oscillator speed (10Mhz, or 20MHz) it’s need and how about the serial speed (like 19200bps or 115200bps). You can write the original .ASM file to your needs, like a 16MHz oscillator and 9600bps. This serial speeds is for bootloading, not for your aplication, so, more speed less time to load your program;
- Burn your MCU with the .HEX;
- Mount your circuit with all normal stuff (reset button, capacitors, etc);
- Conect a serial cable to your MCU. RX-Serial -> TX-MCU and TX-Serial -> RX-MCU (TX-MCU and RX-MCU in 18F252 is 17 and 18 pins). I also recommens a serial converter like these FTDI232RL cables. You found them at SparkFun or Adafruit;
- Connect a 0.1uF (100nF) capacitor between MCLR and the DTR signal of your serial cable.
- Start the Tiny Bootloader. Choose the correct serial speed. Press “Check”. DTR goes high-to-low, reset MCU, and the program detect the PIC type (because the .HEX burned into).
- Now load your program code and download it to MCU. Very fast. Very easy.
thanks for the info. does
thanks for the info. does the charging stop on its own? or do i have to manually turn it off?
what do you mean by burning
what do you mean by burning the MCU with the HEX file? How to do it? can I use pic 16f690
I mean that you need a
I mean that you need a programmer like Olimex MCP USB, or PicKit2, or PICStart+, or any other flash programmer to program your PIC with a Tiny Bootloader .hex file.
Reading the Tiny Bootloader site, I don’t find support for this device (16F690). For 16F family, only a few devices are supported. Therefore, you can:
- Download the Tiny Bootloader and unzip the package downloaded to your computer
- Inside the package you find a directory called “picsource\16f”;
- There’s a file called “tinybld16F.asm”. Open it in MPLAB;
- You can edit some lines and compile it for a PIC16F690 device;
Good luck! If your need some help, email-me.
The charger stop on its own.
The charger stop on its own. Very good!
How did you make your PCB?
How did you make your PCB? Did you use the iron on method? I am only able to use the iron one method. Do you have the PCB schematics that only have the black lines only? I am confused in how to etch it. 