Electronics
GPS receiver - Serial - UP500
- Details
- Category: 8 bits boards
- Hits: 1927
Fig. 1 GPS receiver
Description:
This board is a GPS receiver. It is based around a Fastrax UP500 receiver and interface with a processor board with a serial port. The default protocol is NMEA, 9600 baud, with 8bits, no parity and 1 stop bit.
An on board supercap provides backup voltage to the receiver for quick fix. It can provides backup for up to 48h. After this, the board would do a cold start.
The board interface is an 8 bits type. A set of jumper can select either bit 1 and 2 (PIC16F628 type) or 6 and 7 (PIC18F2320 type) for Rx and Tx connection. Bit 0 provides an optional 1 pulse per second signal.
The board can be powered by 3.3 or 5V processor board.
Specifications:
Input voltage 3 to 5V
InterfaceSerial 9600 baud by default
NMEA protocol
SensitivityCold start -149dBm
Navigation -159dBm
Backup batteryOn board supercap
Schematic:
The power supply is filtered by R3/C1, and C2, charged by D1, provides backup voltage. R1 and R2 offer some protection for the Tx and Rx signal. JP1 allows to select between bits 1-2 or bits 6-7 for these signals. It allows to connect easily the board to PIC16F628 or PIC18F2320 processor boards. JP2 connects the optional 1PPS signal from the GPS receiver to pin 0 of the interface bus.
R5 is here to have an easy Gnd point to connect a test instrument.
Fig. 2 GPS UP500 schematic
Construction:
The PCB fits on a small single sided board. All components are on the top side.
Fig. 3 GPS UP500 layout
Start with the lowest components, and continue with the higher ones. Keep the GPS receiver for last. Solder the 6 pins pinheader to the pcb board.
R5 is made up of a piece of resistor's lead. It's here to easily attach a clip from a test instrument or have a Gnd test point.
Once all the components are soldered, you can test the board as described below and GPS1 can be fitted. Put it on the pinheader and solder it.
Pads 1 to 4 can be drilled to 3mm to fix the board, or put spacers.
| GPS UP500 Component list |
|---|
| C1: 10 uF C2: 0.33 F R1, R2: 1 K R3: 10 R4: 10 K R5: resistor's lead GPS1: Fastrax UP500 D1: 1N4148 JP1: jumper 1x3 JP2: jumper 2x3 K1: Connector AMP MT 10pins male pinheader 6 pins for GPS |
How to use / Testing:
To check the board, connect the board to an 8 bits interface and power up the board. Check you have the Vcc supply on pin 4 and 5 of pinheader.
Switch the power off and check that pin 5 of pinhead still have power, for backup.
To check you get a GPS reading, you need a processor board running the GPS tutorial. Just make sure you set the switches on JP1 to suit the processor used.
The first fix can take a few minutes, depending on your location. Put the board outside, or on a window seal. Inside fix are harder to get.
JP2 is used to ouput a 1 pulse per second from the receiver to pin 0 of the interface bus. It can be used to generate an interrupt every second.
Files and links:
Eagle PCB and schematics files for GPS UP500.PDFs of PCB, layout and schematics of GPS UP500.
PIC Tutorials for GPS UP500.
Fastrax UP500.
8 leds output - 8 bits - leds
- Details
- Category: 8 bits boards
- Hits: 1272
Fig. 1 8 leds output
Description:
This board outputs on leds the 8 bits of an 8 bits port.
Each bit of the port drives a led.
The board can be powered by 2.5 to 5V processor board.
Specifications:
Input voltage2.5 to 5V
Interface8 bits
Schematic:
The schematic is extremely simple. Each bit of the port drives a led through a resistor. The resistor used depends on the led and power supply. I selected 3mm low current red leds, with a 1.6V drop across them, and went for 1.5k resistors, which will give between 0.6 and 2.3 mA in the leds. The leds selected are given for 1mA typically.
Fig. 2 8 leds output schematic
Construction:
The PCB fits on a small single sided board. All components are on the top side.
Fig. 3 8 leds output layout
Once all the components are soldered, the board is ready.
Pads 1 to 4 can be drilled to 3mm to fix the board, or put spacers.
| 8 leds output Component list |
|---|
| R1, R2, R3, R4, R5, R6, R7, R8: 1.5 K R9: resistor's lead LED 1 to 8: 3mm red low current K1: Connector AMP MT 10pins male |
How to use / Testing:
To check the board, you need a processor board running tutorial 1 - counter.
Files and links:
Eagle PCB and schematics files for 8 leds output.PDFs of PCB, layout and schematics of 8 leds output.
PIC Tutorials 1 with 8 leds output board.
LCD Display - 8 bits - Hitachi HD44780
- Details
- Category: 8 bits boards
- Hits: 1948
Fig. 1 LCD Display
Description:
This board implements an alphanumeric LCD display, compatible with Hitachi HD44780 chip. It uses an 8 bits port, but interfaces with the display with 4 bits, so the 8 bits are enough to control the display (data and control lines).
The board will accomodate many types of display, from 1 to 4 lines, and up to 40 caracters per line. A jumper is used to enable the optional backlight.
The example uses a 4x20 display.
The board can be powered by 3.3 or 5V processor board, depending on the specification of the display used.
Specifications:
Input voltage 3.3 to 5V
Interface8 bits with processor
4 bits with display
Number of lignes1, 2 or 4
Nb of caractersUp to 40 per line
Schematic:
The display is connected in 4 bits mode. The 3 control lines (E, RS and RW) takes 3 bits of the 8 bits bus, and 4 are used for the data lines. The data lines are connected to bits 0 to 3. R2 is used to pull up RS, or bit 4. Bit 6 is E and 7 is RW.
JP1 and R3 enable the optional backlight. A jumper across JP1 will switch the backlight on or off.
The contrast is adjusted with R4.
Fig. 2 LCD Display schematic
Bit 5 could easily be used to drive the backlight of the display. A small NPN transistor could be used to switch it on or off. I haven't used it because I often connect the display to port A, and pin 5 is often input only.
Construction:
The PCB fits on a single sided board. All components are on the top side.
Fig. 3 LCD Display layout
Start with the 7 wire links, then continue with the lowest components, and finish with the display. The display can be mounted on some pin header, if it needs to be changed regularly.
Once all the components are soldered, you can test the board as described below.
Pads 1 to 4 can be drilled to 3mm to fix the board, or put spacers.
| LCD Display Component list |
|---|
| C1: 100 nF C2: 22 uF R1: 10 K R2: 100 K R3: 33 R4: Ajustable 1K DS1: Hitachi HD44780 based LCD display JP1: jumper 1x3 K1: Connector AMP MT 10pins male |
How to use / Testing:
To check the board, connect the board to an 8 bits interface and power up the board. When adjusting R4, you should be able to see some lines. This just checks the display is powered. Check the backlight with JP1.
To check the display itself, you need a processor board running the LCD tutorial. Don't forget to check and adjust R4 if the display is blank.
Files and links:
Eagle PCB and schematics files for LCD display.PDFs of PCB, layout and schematics of LCD display.
PIC Tutorials for LCD display.
Hexadecimal display - 8 bits - TIL311
- Details
- Category: 8 bits boards
- Hits: 1618
Fig. 1 Hexadecimal display
Description:
This board shows in hexadecimal the 8 bits of an 8 bits port.
Each bit of the port drives a led.
The board can be powered by 2.5 to 5V processor board.
Specifications:
Input voltage2.5 to 5V
Interface8 bits
Schematic:
The schematic is extremely simple. The 4 lower bits of the 8 bits drives one TIL311, and the 4 upper bits another one. The TIL311 is a chip that display an hexadecimal value of its 4 bits inputs.
Fig. 2 hexadecimal display schematic
Construction:
The PCB fits on a small single sided board. All components are on the top side, just don't forget the 2 wire links, to solder before any other component.
Fig. 3 hexadecimal display layout
Once all the components are soldered, the board is ready. It is possible to fit the TIL311 on 14 pins DIL sockets.
Pads 1 to 4 can be drilled to 3mm to fix the board, or put spacers.
| Hexadecimal display component list |
|---|
| C1: 100 nF U1, U2: TIL311 K1: Connector AMP MT 10pins male |
How to use / Testing:
To check the board, you need a processor board running tutorial 1 - counter.
Files and links:
Eagle PCB and schematics files for hexadecimal display.PDFs of PCB, layout and schematics of hexadecimal display.
PIC Tutorials 1 with hexadecimal display.
TIL311.
Graphic LCD Display - 8 bits - Nokia 3310
- Details
- Category: 8 bits boards
- Hits: 2169
Fig. 1 Graphic LCD Display
Description:
This board implements a graphic LCD display, taken from an old Nokia 3310 phone. It uses an 8 bits port, and the communication with the display is with a serial interface, similar to SPI, with some extra lines: reset, command/data select with the usual clock, data in and chip select. 5 lines are enough to manage the display.
Other types of display can be used, as long as they are compatible with the 3310 display.
2 leds are used to get a backlight on the display.
The display used has 84x38 pixels, but most 3310 types of display will be 84x48 pixels.
The board can be powered by 2.7 to 5V, the board has a basic regulator to suplly the display with 3.3V.
Specifications:
Input voltage 2.7 to 5V
Interface8 bits with processor
Display size84x38 pixels
Schematic:
C2 filters the supply voltage, C1 is used by the display charge pump. Each lines is then connected to a bit of an 8 bits bus.
A backlight circuit is based around R1, LED1 and 2. It also drives Q1 the transistor that limits the supply to the lcd display.
Depending on the led used, the voltage across one of them is around 1.6V. With 2, we get 3.2V. We add the base/emitter junction voltage, and we get a simple voltage regulator of around 3.8V. If you don't need a backlight, you can replace the 2 leds with a 2.7V zener diode, which will give you about 3.3V for the display.
C3 filters the power supply to the display itself.
Fig. 2 Graphic LCD Display Nokia 3310 schematic
Construction:
The PCB fits on a single sided board. All components are on the top side (copper side) except Q1.
Fig. 3 Graphic LCD Display Nokia 3310 layout
Start with the lowest components: C3 and the leds and the resistors. Continue with C1, C2 and Q1. Q1 is on the bottom side to make room for the display.
For the display, it depends on the pads. My display has 'spring' contacts. I positionned the display on the connecting pads, and kept it pressed down with some electrical tape. You can run a tutorial with the graphic LCD display to make sure it is positionned properly before securing it.
| Graphic LCD Display Component list |
|---|
| C1: 4.7 uF tantalum C2: 22 uF tantalum C3: 100 nF smd R1: 100 R2: 22 T1: BC547 or equivalent NPN LED1, LED2: green led smd LCD1: Nokia 3310 LCD display K1: Connector AMP MT 10pins male |
How to use / Testing:
To check the board, you need a processor board running the graphic LCD tutorial.
Files and links:
Eagle PCB and schematics files for graphic LCD display.PDFs of PCB, layout and schematics of graphic LCD display.
PIC Tutorials for graphic LCD display.
Philips PCD8544 graphic LCD controler.