Attiny85 backpack programmer header


Facelesstech published a new build:

So when I was into using just a atmega328 dip chip I make a programmer header for it that also had a crystal and the capacitors need to make it function. I wanted to do the same for the attiny85. As you know you have to use a ISP programmer to flash the attiny85, This requires you to look up the pinouts and get a bunch of jumps out to wire it up. I wanted to eliminate all of this.

More details at Facelesstech site. Github link here.

Check out the video after the break.

WGX iBeacons

In a recent tutorial I explained how to detect the presence of an iBeacon with the esp32 chip. The iBeacon used to demonstrate the program is manufactured by a chinese Company, Wellcore, and sold by Banggood.

The transmitter is enclosed in a plastic, non waterproof, case of 4x4cm size:

wgx-001 wgx-002

The enclosure has a hole that allows you to hang the iBeacon on the wall or alternatively use it as a key ring.

The transmitter is based on a double-sided circuit board: one side hosts all the components, while on the other side you find the lithium battery that powers the iBeacon. The antenna is also printed directly on the PCB.

A switch allows you to turn the iBeacon on or off:

wgx-003 wgx-004

Unlike Bangood says, this iBeacon is based on the Nordic nRF51822 chip:


The use is very simple: just turn the iBeacon on and it continuously transmits the advertising package containing its unique UUID.

The manufacturer also offers an application to customize some parameters of the iBeacon. For iOS smartphones you can download the “Wellcore Beacon Tool” app from the App Store, while for Android the apk file of the application is available for download on this website.

The app performs a scan looking for compatible iBeacons:


Once found an iBeacon, you can change some of its parameters (in the example, its name):


The change is effective as soon as you click the Write command:


App note: Sub-1 V current sensing with the TS1001, A 0.8 V, 0.6 µA OP-AMP


Another TS1001 op-amp application from Silicon Labs on sensing nano currents. Link here (PDF)

Current-sense amplifiers can monitor battery or solar cell currents, and are useful to estimate power capacity and remaining life. However, if the battery or solar source is a single cell, it’s difficult to find a low voltage solution that works below 1V and draws just microamps. A new class of nanopower analog ICs, namely the TS1001 0.8 V/0.6 µA op amp, makes a sub-1 V supply current sense amplifier possible. This discrete circuit operates from as low as 0.8 V and draws 860 nA at no load while providing a 0–500 mV output for measured currents of 0–100 mA, though the scale can be adjusted by changing the values of a few resistors. With its extremely low power, the circuit can simply remain “always on,” providing a continuously monitored, averaged indication of current which can subsequently be read periodically by a microcontroller, without causing too much current drain in the battery.

App note: A microwatt charge pump boosts 1 V to 1.8 V at 90% efficiency, providing “Always On” standby power for microcontrollers


Interesting app note from Silicon Labs on high efficiency charge pump utilizing their nanopower TS1001 op amp. Link here (PDF)

Boosting the output voltage of common alkaline button-cells to at least 1.8 V needed by microcontrollers provides an “always on” standby power source sufficient for low-power oscillator interrupt/sleep state operation. Two ultralow power op amps are used in a charge pump configuration to double an input voltage, creating an output voltage of approximately 2x the input voltage. Output currents up to 100 µA are available at 90% efficiency; even load currents as low as 10 µA achieve 80% efficiency, beating commercially available charge pump ICs and inductorbased boost regulators.

HP 8620C sweep generator repaired


Kerry Wong did a repair of an HP 8620C sweep generator we covered previously:

In my previous post, I did a teardown of an HP 8620C sweep generator along with an HP 86245A 5.9 GHz to 12.4 GHz RF plugin. A few of the plguin boards in the 8620C had leaked capacitors and also there seemed to be some sort of mechanical issue as no power was delivered to the transformer regardless of the power switch positions. So what I planed to do next was to restore the power to the unit and replace those bad capacitors and see if I could bring this sweep generator back to life.

See the full post on his blog here.

Check out the video after the break.

Implementing FizzBuzz on an FPGA


Ken Shirriff writes:

I recently started FPGA programming and figured it would be fun to use an FPGA to implement the FizzBuzz algorithm. An FPGA (Field-Programmable Gate Array) is an interesting chip that you can program to implement arbitrary digital logic. This lets you build a complex digital circuit without wiring up individual gates and flip flops. It’s like having a custom chip that can be anything from a logic analyzer to a microprocessor to a video generator.
The “FizzBuzz test” is to write a program that prints the numbers from 1 to 100, except multiples of 3 are replaced with the word “Fizz”, multiples of 5 with “Buzz” and multiples of both with “FizzBuzz”. Since FizzBuzz can be implemented in a few lines of code, it is used as a programming interview question to weed out people who can’t program at all.

More details at Ken Shirriff’s blog.

10MHz distribution amplifier


G4FRE built a 10MHz distribution amplifier:

I have had a need for a distribution amplifier for a while now. Searching around I found the design by G4JNT in Radcom, which filled my needs. I redrew the circuit for 4 outputs and had PCBs made. (if you want one contact me!)  I now have the units in my M1DST 10MHz Thunderbolt monitoring project and in my LPRO101 10MHz Rubidium source.

See the full post on his blog here.

Laser arm


Facelesstech published a new build:

So some time last year I ordered one of those servo 2 axes (pan and tilt torret) arm kits from aliexpress. It was fun to play with but I didn’t quite find a reason to use it in a project. Then I seen this project on hackaday and a light bulb went off in my head, Why hadn’t I thought about adding a laser to the arm. This would be great to let your cat or dog play with or drive them mad.


Check out the video after the break.