Shared Projects

RS-232 null modem adapter board.

Edge-solder two DB9F connectors on either side of the board (DigiKey 4209FE-ND, for instance) and you get an RS-232 null modem. The pinout:

• TXD<->RXD
• RTS<->CTS
• GND<->GND
• DTR->DSR+DCD (x2)
• RI->nc (x2)

Mini Brushless Gimbal Controler. Oryginal Idea by OlliW

Add a i2c ADC to your OpenRov Control Board V 2.6 or 2.5 and test the boards power supplies and i2c.

Create up to four sounds and trigger them by pressing buttons

This board receives the signal from a wireless heart rate transmitter chest strap. It outputs a 10ms TTL level pulse with each heart beat. Tested with Polar T31 (uncoded) and H1 (coded) 5.5kHz transmitter straps.

Distortion with Mosfet based clipping section. Documentation is available here.

Lasertag compatible health sensor. Board sized to replace the pcb in a flashing bike light housing.

More Info: http://lt-mmo.blogspot.com/search/label/Feral%20IR%20Sensor

Clone ULA TK90X e TK95

Project details: http://www.victortrucco.com/TK/ULATKCPLD/ULACPLD_Altera.zip

This board is a meta-breakout board for Pololu’s DRV8825 stepper driver module, designed to hold a custom-machined heatsink, capacitor, screw-terminal connectors, and an indicator LED for fault conditions.

• C1 is a Panasonic H13 100µF 63V electrolytic capacitor (EEE-TK1J101AQ).
• D1 is an 1206 red LED - OSRAM’s LH N974-KN-1
• Q2 is a P-channel MOSFET - NXP BSS84,215. Q1 and R1 are non-existent.
• R2 is an appropriately-sized 0805 current-limiting resistor for your choice of LED.
• JP3 and JP4 are TE Connectivity 284391-4 and 284391-2, respectively.

Cost: $3.60 for three.

Description:

Breakout board for the Analog Devices AD8495CRMZ K-Type Thermocouple Amplifier. This IC reads thermocouple input and scales it to 5mV (0.005V) per °C (plus a 1.25V reference offset). This output can be read by a microcontroller or a multimeter; simply subtract 1.25 from the output, then multiply by 200 to get the temperature.

U3 (Texas Instruments LP2980) is a 4.7V low dropout linear regulator which provides Vcc for U1 (Analog Devices AD8495) and U2 (Analog Devices AD8613), and also feeds a voltage divider comprising R4 and R5. 1.25V from this divider is buffered through op-amp U2 to the reference pin of U1, providing a positive offset to allow measurement of negative temperatures. The thermocouple inputs to U1 are configured with a 1kHz low pass filter for noise rejection.

This board offers a measurement range of about -25 to +400°C with maximum error of +/-2°C. Measurements are possible outside this range (roughly -200 to +900°C), with larger errors due to thermocouple nonlinearity.

An exposed ground pad is provided near the thermocouple connector for ambient temperature sensing or debugging (see AD8495 datasheet, page 13). For permanent configuration as an ambient temperature sensor, use the AD8494CRMZ instead, as its output is more linear in this configuration.

Bill of Materials:

• U1: Analog Devices AD8495CRMZ K-Type Thermocouple Amplifier (8-MSOP) – NOTE: Both Mouser and Newark have this part in stock at lower prices.
• U2: Analog Devices AD8613AUJZ-R2 Operational Amplifier (SOT-23-5)
• U3: Texas Instruments LP2980AIM5X-4.7 4.7V LDO Linear Regulator (SOT-23-5)
• C1: AVX Corp F931C106KAA 10µF 16V Tantalum Capacitor (1206)
• C2, C6: Kemet C0603C104K4RACTU 0.1µF 16V Ceramic Capacitor (0603)
• C3, C4: Taiyo Yuden TMK107BJ105KA-T 1µF 25V Ceramic Capacitor (0603)
• C5: Yageo CC0805KKX5R5BB106 10µF 6.3V Ceramic Capacitor (0805)
• R1: Stackpole RMCF0603FT1M00 1MΩ 1/10W 1% Resistor (0603)
• R2, R3: Stackpole RMCF0603FT160R 160Ω 1/10W 1% Resistor (0603)
• R4: Stackpole RMCF0603FT31K6 31.6kΩ 1/10W 1% Resistor (0603)
• R5: Stackpole RMCF0603FT11K5 11.5kΩ 1/10W 1% Resistor (0603)
• J1: On Shore Technology OSTVN02A150 2-Position Screw Terminal
• J2: On Shore Technology OSTVN04A150 4-Position Screw Terminal -or- Sullins Connector PREC004SAAN-RC 4-Position Pin Header

BOM Cost: $12.83 + Thermocouple

K-type thermocouples and in-line connectors are available on eBay for $1.25 or less, delivered. Female panel-mount connectors are available from Auber Instruments for a few dollars.

Notes:

1. Input voltage should be a minimum of 5VDC to a maximum of 14VDC. Current draw is less than 3mA. My board runs perfectly on a 9V battery. U3 dropout voltage is maximum 225mV, so any Vin below about 4.925V may affect accuracy. If you power the board from a 5V source, measure voltage at U3 pin 1 to ensure adequate Vin.

2. Do not substitute alternate parts for C1. U3 is sensitive to ESR and this cap was selected to fall within its permitted range. C1 is a polarized capacitor; ensure that the mark on this device matches the mark on the board (bar to the right).

3. For best accuracy, use K-type thermocouple wire (chromel/alumel) all the way to the board. If you use a panel-mount connector on an enclosure, use additional K-type wire (available here or here) from the connector to the board. It may be cheaper to buy an extra thermocouple on eBay and cut off the wire you need.

4. For maximum temperature calculation accuracy, measure the voltage at the pad marked “REF”. This is the reference offset voltage, which is nominally 1.254V but which may differ due to LDO, resistor and op-amp tolerances. This exact measurement should be subtracted from the output before multiplying by 200. On my board, with Vin=9V, REF measures 1.2487V

5. For complete information on using this board with a microcontroller and compensating for thermocouple nonlinearity, see this application note.

PCB for the LPC11U24 Gadget project. Contains a USB-connected NXP LPC11U24 microcontroller and an integrated ARM debugger. BOM and build instructions TBD.

Photo and Announcement

A breakout board for the Laird BL600 Bluetooth Low Energy (Bluetooth 4.0) surface-mount module.

A narrow breakout board for the BlueGiga BLE112 designed for easy breadboard use. Places the module off the edge of the breadboard for better antenna performance.

double the blink on Contextual Electronics

Padiddle game to be played in car. For use with arduino or external microcontroller.